Giant Hogweed (Heracleum mantegazzianum Sommier & Levier) was first recognized by the federal government as a noxious weed in 1983. It originated in the caucus mountains of Asia. The infestation in the United States is the product of homeowners growing the plant in their gardens as an ornamental. The seeds then spread into roadside ditches, streams, etc. via water dispersion and birds. Populations have been found in 16 states. The Pennsylvania Department of Agriculture, in conjunction with the United States Department of Agriculture, started its Giant Hogweed Eradication Program in 1998. Since then over 500 sites have been found and treated in Pennsylvania in 17 counties. More than 55% of the populations are located in Erie County. In March, 2010 Pennsylvania had identified 296 sites for declaring officially eradicated. Many of these sites were known to be inactive for more than 7 years. PDA has adopted a three year negative seedbank followed by three years of follow-up surveys as the standard for officially releasing a site as eradicated. 

   Each season, the PDA hires a seasonal giant hogweed (GH) field position for Erie County and surrounding counties. This person is responsible for 1) managing the state giant hogweed hotline and 2) surveying all known active sites and 3) surveying as many released sites and hotline call locations as possible between May and August for the presence of the noxious weed. Many of the sites are in very difficult to reach locations and the plant, in its cotyledon and early rosette stage, can be easily overlooked. To assist the surveyors in locating GH, a database of addresses, property owners contact information, GPS coordinates, and site descriptors has been compiled. However, addresses change, landowners move, and in some cases, the landscape itself is completely changed. These factors and the lack of site location knowledge in new hires make finding the correct locations very challenging. State-wide, 162 active and 262 released sites were visited. Fifty-two of the 166 active sites were positive for giant hogweed plants and 10 new sites were detected. In addition, 14 released sites were re-discovered to be active.  

   Given that a single GH plant can produce more than 10,000 viable seeds the PDA is working to improve its survey and detection methods to address the correlation of time (7-12 years since site was released) and re-discovering a released site with the data available. This paper summarizes the materials and methods used by the Erie County GH hire to find 88% of 279 released sites through follow-up visits and 98% of 101 active sites in the assigned 4 counties and the relationship between surveying methods and successful eradication of spatially related populations. By improving and expanding upon the survey methodology used to re-locate released sites of GH and to detect new locations, 9 released sites were rediscovered that were still active and 6 new sites were found that were spatially related to known active sites. This information will be used to prioritize surveys of released sites in 2011 and in developing future survey methodology for noxious weed detections.

   Corallita (Antigonon leptopus) is a perennial vine, lauded as an ornamental for its vigorous growth, plentiful (usually) pink flowers, and even its ability to smother unsightly landscapes. In the United States it thrives in horticultural zones 8 - 10 and is also successfully grown worldwide in tropical climes. When Corallita is neglected, it can quickly grow over other vegetation, spreading beyond its introduced area. Once established, it is difficult to eradicate since it produces many tuberous roots that can propagate vegetatively. Its fruits are buoyant, allowing for successful seed dispersal in water. The islands of Guam (South Pacific Ocean) and St. Eustatius (Caribbean Sea) represent two regions where Corallita has become so pervasive it threatens local diversity. In Florida it is already classified as a Category II invasive. Our report adds taxonomic information to clarify the identity and range of Antigonon leptopus, and a preliminary study on St. Eustatius provides data on phenology, dispersal mechanisms, and efficacy of herbicidal control.

   A field-container experiment was conducted in Morgantown, WV, in 2010, to determine the tolerance of drift rose (Rosa spp. 'Meiggili' Peach Drift), Japanese barberry (Berberis thumbergii var. atropurpurea), and butterfly bush (Budleia davidii 'Blue Chip') to sequential over-the-top applications of sulfosulfuron at 0.066 kg ai/ha (low), 0.131 kg ai/ha (medium), and 0.262 kg ai/ha (high), six weeks apart.  At the time of initial and second herbicide applications, on Jul 23 and Sept 23, untreated rose plants were 25 and 30 cm; Japanese barberry, 35 and 40 cm; and butterfly bush, 60 and 70 cm tall, respectively.  Rose expressed phytotoxicity symptoms 10 d after herbicide application which progressed till three weeks after treatment (WAT).  On a 0-10 scale, phytotoxicity ratings averaged 1 for the low rate of herbicide, and 2 for medium and high rates, at 3 WAT.   At 4 WAT, phytotoxicity ratings averaged 1 for all application rates in conjunction with increased apical dominance and normal new growth.  However, roses treated with sulfosulfuron exhibited bloom-delay by a month for each flush and resulted in fewer flowers overall, compared to untreated plants, till 12 WAT at all rates of application.  The second application of sulfosulfuron caused more injury to plants already treated, with average phytotoxicity ratings ranging from 2 to 4 for low to high rates of sulfosulfuron, at 2 weeks after second application.  The recovery of treated roses was slower and injury symptoms persisted till 6 WAT along with a severe (~90%) reduction in bloom, compared to untreated plants.  Initial phytotoxicity symptoms due to sulfosulfuron application on roses manifested as reduced leaf expansion, mild to moderate chlorosis followed by mild necrosis and leaf puckering.  Japanese barberry and butterfly bush tolerated sulfosulfuron at all application rates without manifesting any phytotoxicity symptoms.  

   Sweet vernalgrass (Anthoxanthum odoratum)  is a perennial grass weed found in cool-season turfgrass. It is highly competitive in the spring due to its rapid growth, early flowering, and potential allelopathic suppression. Sweet vernalgrass also has a high potassium requirement. It can easily adapt to new environmental conditions; research has shown that significant differences in morphologies, flowering dates, and seed yields have occurred due to genetic adaption to new environments. Sweet vernalgrass is very difficult to control. An experiment was conducted near Richmond, Virginia to determine herbicide options for sweet vernalgrass control in cool-season turf. Seven herbicide treatments were evaluated. At 34 DAT, MSMA at 2.1 kg a.i. ha^-1, mesotrione applied once at 0.28 kg a.i. ha^-1, and mesotrione applied twice at 0.14 kg a.i. ha^-1 controlled sweet vernalgrass 73, 63, and 57%, respectively. At 71 DAT, control by MSMA declined to 40%, whereas mesotrione applied once and mesotrione applied twice controlled sweet vernalgrass 67 to 100%. Rapid growth of sweet vernalgrass in the spring might explain why mesotrione applied once provided the best control as this herbicide tends to be more effective during rapid growth phases of susceptible plants. Applying more active ingredient during sweet vernalgrass peak growth seems to play an important role in its control. Decline of MSMA control can likely be explained by MSMA’s contact activity and the perennial nature of the weed. Fenoxaprop, quinclorac, amicarbazone, methiozolin, and sulfentrazone did not control sweet vernalgrass.                  

   Field studies were conducted in the fall of 2009 and 2010 to evaluate the length of residual weed control of annual bluegrass (Poa annua) on bare soil.  Herbicides were applied to bare soil (Freehold sandy-loam with pH 6.4 and 2% organic matter).  The compounds under evaluation were: mesotrione at 0.28 and 0.43 kg ai/ha, dithiopyr at 0.28 and 0.43 kg ai/ha, prodiamine at 0.57 and 0.74 kg ai/ha, and bensulide at 9.41 and 11.91 kg ai/ha.  All applications were made using a single 9504EVS nozzle CO₂ pressured sprayer calibrated to deliver 378 L/ha at 207 kPa.  The study was visually evaluated at 4 and 8 weeks after treatment (WAT) and the following spring for Poa annua control. The plots were evaluated for percent control and percent cover of Poa annua, both on a scale of 0 (no control or cover) to 100 (complete control or cover).   Annual broadleaf weeds were evaluated also at 4 WAT.   Control of Poa annua ranged from 70% to 90% between the four compounds examined.  Mesotrione was the only compound which showed significant difference between rates applied, 70% and 86%, respectively.  All other compounds provided between 79% and 90% control, respectively.  In springtime, mesotrione was found to only provide 31% to 44% control of Poa annua as opposed to the 81% to 85% provided by dithiopyr, 81% to 89% provided by prodiamine and 82% to 85% provided by bensulide.  Annual broadleaf weeds, common chickweed (Stellaria media) and henbit (Lamium amplexicaule), were controlled with mesotrione.  The result of one year of research suggests that the broad spectrum herbicides (dithiopyr, prodiamine, and bensulide) control Poa annua better than mesotrione as demonstrated by decreased control of mesotrione over time. 

At no time during this study was bermudagrass injury observed. Applied EPRE, F9001 SC at ≥706 g ai/ha controlled yellow nutsedge ≥ 88% at 105 DAIT through the end of the study. F9001 SC at 493 g ai/ha applied EPRE controlled yellow nutsedge 83% at 105 and 134 DAIT. All rates of F9001 SC applied LPRE controlled yellow nutsedge ≥87% on all rating dates.  F9001 G applied EPRE and LPRE at 908 g ai/ha controlled yellow nutsedge ≥ 87% at all rating dates. EPRE applications of F9001 G at ≤ 706 g ai/ha controlled yellow nutsedge ≤ 85% at 105 DAIT through the end of the study. LPRE applications of F9001 G at rates ≤ 706 g ai/ha controlled yellow nutsedge ≤ 90% at 105 DAIT through the end of the study. Applied EPRE and LPRE, sulfentrazone + prodiamine controlled yellow nutsedge ≥87% at 105 DAIT. Sulfentrazone + prodiamine control of yellow nutsedge reduced to ≤83% at 134 DAIT for both timings. Both formulations of dithiopyr controlled yellow nutsedge 0% at all rating dates. These data suggest that F9001 can be used to provide preeemergence control of yellow nutsedge.

   Annual bluegrass (Poa annua L.) is perhaps the most common and problematic weed on creeping bentgrass (Agrostis stolonifera L.) putting greens.  Various field trials have been conducted to investigate the influence of select plant growth regulators (PGRs) and fertility regimes on annual bluegrass (ABG) populations.  Few studies, however, have investigated the interactions among these factors in combination with ferrous sulfate; an increasingly popular ABG management regime for golf course turf.  The objective of this project is to elucidate the interactions of three cultural and chemical management strategies on ABG populations on golf course putting greens.  Four field studies were initiated in the spring of 2010 at the Joseph Valentine Turfgrass Research Center located in University Park, PA.  Trials were conducted on a mature stand of ‘L-93’ creeping bentgrass with approximately 25% ABG when the study was initiated.  The area was mowed six times per week at a height of 2.5 to 3.2 mm.  All trials were exposed to minimum surface disturbance and received no supplemental phosphorous.  Plots measured 0.9 x 1.8 m and were arranged in a randomized complete block design with a factorial treatment structure.  The four studies consisted of either a 2 x 3 or 2 x 3 x 3 factorial with the main factors of nitrogen (N) rates, plant growth regulators, and ferrous sulfate rates. Treatments were initiated on 26 May and applied approximately every 3 weeks throughout the season.  All treatments were applied in 4073 L H₂O/HA.  Seasonal fluctuations in ABG populations were observed during the study. When ABG populations were highest, plots receiving flurprimidol provided the greatest suppression of ABG when compared to all other treatments. Populations of ABG were generally lower in plots receiving low seasonal nitrogen (25 kg N/HA/year) when compared to plots receiving high seasonal nitrogen inputs (107 kg N/HA/year).  Additionally, applications of trinexapac-ethyl to low N plots resulted in a 58% reduction of ABG when compared to plots receiving no PGR.  This result, however, was not observed within plots receiving 107 kg N/HA/year. Although ferrous sulfate (all rates and combinations) had little impact on ABG populations, it was effective at improving turf color. The effects of these cultural and chemical interactions will continue to be assessed to determine any long term positive or negative impacts on species segregation and overall turf quality.

   Hairy vetch (Vicia villosa Roth) is an important cover crop option for organic and conventional farmers in the Northeast. There is considerable interest in utilization of hairy vetch as a cover crop and its potential benefits for nitrogen fixation, weed suppression, and erosion control. However, adoption of hairy vetch by some producers has been limited due to negative farmer experience and the perception that hairy vetch can be invasive, particularly in organic systems. The focus of this project is to examine organic and conventional management options for selective control of hairy vetch in winter wheat (Triticum aestivum L.). Experiments were conducted in 2009 at the Rock Springs Agronomy farm in Centre County, Pennsylvania and the Beltsville Agricultural Research Center in Beltsville, Maryland. Two studies were organized as randomized complete blocks with four replications. In early October, 11.2 kg/ha hairy vetch was seeded with 134.5 kg/ha winter wheat. Organic management tactics examined timing (fall vs. spring) and rate of application of three potential organic herbicides and propane flaming. Treatments included acetic acid (vinegar), ammonium nonanoate (Racer™), and lemon grass oil (GreenMatch™) applied at 0.5X and 1X the recommended rates. Propane flame treatments included two rates. Conventional herbicide treatments included 2,4-D amine, dicamba, MCPA amine, clopyralid, thifensulfuron, tribenuron, thifensulfuron + tribenuron, mesosulfuron, prosulfuron, pyroxsulam, and carfentrazone applied at varied rates and combinations in the fall and spring. Visual efficacy ratings (0 to 100%) for hairy vetch control and wheat injury were determined for all treatments and hairy vetch and wheat above ground plant biomass was collected from a 0.5 m2 quadrat per plot. Wheat grain was harvested with a small plot combine. Hairy vetch biomass in untreated plots for the conventional study at Rock Springs averaged 833 kg/ha. In the conventional study, fall treatments were generally less effective than spring. Fall applied clopyralid and spring treatments of dicamba, dicamba + 2,4-D, tribenuron, mesosulfuron, pyroxsulam, and clopyralid all decreased mean hairy vetch biomass below six kg/ha. Wheat yields for these treatments averaged 3994 to 4841kg/ha compared to 3191 kg/ha in untreated plots. Mean hairy vetch biomass and wheat yield of untreated organic management plots were 1152 and 3770 kg/ha, respectively. Most of the organic treatments did not effectively control hairy vetch. The high rate of flaming in the fall was the only organic treatment that reduced average hairy vetch biomass below 100 kg/ha with a mean wheat yield of 5095 kg/ha.

   Since the loss of organometallic herbicides, prevalence of silvery threadmoss (Bryum argenteum) in golf course putting greens has increased. Demands for faster playing surfaces have led to reduced putting green mowing heights and fertility, creating perfect conditions for competitive displacement of creeping bentgrass by silvery threadmoss. Currently only one professional herbicide, carfentrazone (Quicksilver) and two fungicides, chlorothalonil (Daconil) and mancozeb (Manzeb) are labeled for moss control on putting greens. With a limited number of products available, the golf industry has experimented with off-label products with moderate success, including baking soda, lime, iron-containing fertilizers, and Ultra Dawn dish detergent. Research to date has not provided a solid understanding of which chemistries work and which do not. The goal of this research is to more thoroughly screen available crop protection chemicals for effects on silvery threadmoss and ultimately discover new options for its control. 

   A preliminary herbicide screen on silvery threadmoss was established as a randomized complete block design with ten replications. It included 49 herbicides applied at one and two times the labeled use rate and a non-treated control. Over 1200 actively growing moss plugs approximately 1cm in diameter were collected from a bentgrass putting green and separated into groups of 99 plugs for each of the ten replicates. For each of 98 herbicide treatments, ten moss plugs were treated in a spray chamber calibrated at 814 L/ha. After treatment, plugs were randomly placed into 24-well cell culture plates. Photos were taken at 0, 3, 7, 10, 14, 21, and 28 days after treatment (DAT) and data were captured in Sigma Scan Pro 5. Sigma Scan counted green pixels in the range of hue=38 to 100 and saturation=0 to 100. When compared to the 0 DAT pixel counts, % reduction in green color was calculated for each moss plug which we equate to a measure of control. Data were subject to ANOVA and means separated by Fishers protected LSD (p=0.05). At 3 DAT, carfentrazone reduced green color 55% and pelargonic acid reduced green color by 89% and more than all other treatments.  Other herbicides which significantly reduced green color included: flumioxazin, MSMA, glufosinate, sulfentrazone, and an experimental. By 10 DAT, several herbicides reduced green color by more than 90% including flumioxazin, carfentrazone, fosamine, diquat, and sulfentrazone. However, by this time fungal growth over the moss plugs was significantly limiting ability to attribute reduction in green color to herbicide activity versus fungal growth; the nontreated control plugs had 70% reduction in green color where no herbicide was applied.  

The study was completed despite the fungal problem and this preliminary screening supported previous literature reports that carfentrazone, flumioxazin, and pelargonic acid effectively control silvery threadmoss. We were not able to support findings that oxadiazon and oxyfluorofen are effective but several chemicals were added to the list of potential candidates for moss control, including: an experimental product, MSMA, sulfentrazone, and fosamine. Fungicide and surface sterilization screens are in progress to develop a procedure to prevent fungal growth in future chemical screens.  Herbicides, fungicides, plant growth regulators, adjuvants, and biocontrol organisms are slated for future evaluation.

   Annual bluegrass (Poa annua) and roughstalk bluegrass (Poa trivialis) are annual grassy weeds that commonly infest home lawns in the United States.  In cool climates, lawns are typically comprised of tall fescue (Festuca arundinacea), perennial ryegrass (Lolium perenne), and Kentucky bluegrass (Poa pratensis).   Methiozolin is a new herbicide under evaluation by the Moghu research Center in South Korea for use in several turfgrass species. Three trials were initiated at the Glade Road Research Facility in Blacksburg, VA on April 19, 2010 to evaluate annual and roughstalk bluegrass control and turfgrass response to methiozolin compared to an industry standard. The first trial location was perennial ryegrass infested with annual and roughstalk bluegrass mown at 3.81 cm. The second location was Kentucky bluegrass contaminated with white clover (Trifolium repens) maintained at 3.81 cm. The third site was a weed-free area of tall fescue mown at 6.35 cm. Treatments were replicated 3 times in a randomized complete block design (RCBD) and applied using a CO₂ backpack sprayer calibrated at 280 L/ha. Treatments included; methiozolin at 500, 1000, 1500, 2000, 3000, and 4000 g ai/ha, bispyribac-sodium (Velocity) at 74 g ai/ha, and a non-treated check (NTC). All methiozolin treatments 2000 g ai/ha or less and bispyribac-sodium treatments were repeated one month after initiation on May 19, 2010. Methiozolin did not injure any turf species at any timing. Bispyribac-sodium injured perennial ryegrass 20%, tall fescue 15%, and Kentucky bluegrass 60% at nine days after the second treatment. At rates above 1500 g ai/ha, methiozolin suppressed annual bluegrass seedheads by at least 85% one week after the first treatment. Bispyribac-sodium also reduced annual bluegrass seedheads by 85% at the same timing. Bispyribac-sodium controlled white clover at two locations, while methiozolin did not affect white clover populations at any rating. At 29 days after treatment (DAT), methiozolin at 2000 g/ha applied twice and 3000 or 4000 g/ha applied once controlled roughstalk bluegrass 60, 90, and 92%, respectively, compared to 90% control from bispyribac-sodium. At 49 DAT, methiozolin at 1500 and 2000 g ai/ha applied twice controlled annual bluegrass 84% and 94% respectively. Methiozolin at 3000 and 4000 g ai/ha applied once controlled annual bluegrass 85% and 93%, respectively at the same rating date. Bispyribac-sodium applied twice controlled annual bluegrass 38% 49 DAT. These results suggest that methiozolin could be a safe and effective herbicide for post emergence control of both annual and roughstalk bluegrass in a variety of cool season turfgrass situations.         

   Soybean production has increased steadily both in the United States and New York State in the last 20 years.  As new soybean growers enter production, agronomic factors such as optimal row spacing to be used become increasingly important.  Soybeans are currently planted in 19 cm rows using a grain drill or in 38 cm and 76 cm rows using a corn planter.  Recent studies show that planting soybeans in narrow rows lead to a yield advantage over soybeans planted in wider rows in northern latitudes.  One of the goals of this 2-year field study was to determine the impact of soybean row spacing on weed abundance and soybean yield under NY State growing conditions. This research was initiated on three collaborator farms in the major soybean production regions of New York.  At each of the three locations, soybeans were seeded at approximate populations of 309,000 and 420,000 plants/ha at three row spacings (19, 38, and 76 cm widths). There were three replicates of each row spacing treatment at each location.  One of the sites received a pre-emergence application of Enlite (premix of flumioxazin, chlorimuron- ethyl and thifensulfuron-methyl at 0.204 liters /ha), which resulted in very low weed densities during the 2010 growing season. The other two sites, which received early summer applications of glyphosate at 429.3 g a.i./ha, did have greater weed densities than the pre-emergence site.  Weed densities were determined before herbicide application and at two post-application times. A total of 2.0 meters was sampled in each row spacing treatment using a 1 m X 0.5 m quadrat.  Dry weed biomass within each row spacing treatment was determined at harvest.  Soybeans plots planted in narrow rows (19 cm) had substantially lower weed densities compared to soybeans planted at the two wider row spacing after herbicide application. In general, the narrow row soybean plots also had lower weed biomass at harvest compared with the wider row spacings.  However, while weed pressure differed between row spacing treatments, soybean yield did not differ (3600 to 3750 kg/hectare at the low and high seeding rates for all three row spacings).  The 2010 growing season provided very favorable conditions for soybean growth, which may have reduced the impact of weed competition on yield.  We will conduct this study in 2011 to determine if results are consistent across years. 

   In the Northeastern U.S., dairy and organic vegetable producers commonly use manure or compost to meet the nutrient needs of crops. Application at rates needed to meet the nitrogen (N) needs of the crops will result in overfertilization with phosphorus (P), potassium (K), and other nutrients over time due to the relatively low N content and challenges in retaining the N for crop uptake.

   Since 2005, researchers at Cornell University have been conducting a long-term study comparing organic cropping systems. One of the findings of this study is that when compost application rates increase, weed growth also increases.

   In the summer of 2010 a field experiment was initiated to partition out the effects of N, P, and K from composted poultry manure on weed growth. Corn (Zea mays), lettuce (Lactuca sativa), Powell amaranth (Amaranthus powellii), common lambsquarters (Chenopodium album), and giant foxtail (Setaria faberi) were grown individually in open-bottomed wooden boxes. The boxes were set into the soil and filled with soil amended with composted poultry manure (6-2-2) [N-P-K], blood meal (12-0-0), bone char (0-16-0), K sulfate (0-0-50), or the latter three together. Four amendment rates were designed to mimic the N, P, and K in composted poultry manure. These rates span from well below what a producer would generally apply to well above. Control plants were also grown with no nutrient amendments. The unamended soil was low in P, moderate in K, and high in calcium (Ca).  It had moderate N from clover and alfalfa in the plowed sod.  Research is ongoing to test the nutrient release from blood meal as a N source (N release dynamics over time).       

   The lack of corn response and the positive weed response to composted manure supports our hypothesis that compost amendment above crop needs increases weed growth. The results observed with the other amendments are consistent with the hypothesis that (1) P was the limiting element in this experiment and that (2) P from bone char was immobilized by the high level of Ca in the soil. 

   Rye and hairy vetch are common cover crops that can be planted for erosion control, soil fertility, or weed control in no-tillage production systems. Research has shown that both cover crops, separate or combined, can provide varying degrees of weed suppression in no-tillage corn. Corn producers in Virginia have financial incentives available to them for planting winter small grain cover crops. The addition of hairy vetch to small grain cover crops is utilized by some producers to increase nitrogen levels in the soil. Most producers desiccate these cover crops in March. This allows for minimal residue levels that do not impede on corn planting. If allowed to grow, rye and hairy vetch cover crops will produce more residues and may provide supplemental weed suppression that allows for a reduction in herbicide inputs without a loss in weed control or crop yield. Experiments were conducted in Virginia to determine if rye and rye/ vetch cover crops provide enough additional weed suppression to allow reduced herbicide rates. Six different herbicide combinations were applied in three different cover crop residue levels. Cover crop residue levels were determined by time of desiccation. March desiccation resulted in no cover crop residues. Early April desiccation resulted in low residue levels and late April desiccation resulted in higher residue levels. Rye residue levels ranged from 1,773 to 5,889 kg/ha and rye/vetch residue levels ranged from 2,108 to 3,855 kg/ha. Early season weed control was greatest with atrazine, metolachlor, and mesotrione PRE at 0.7+1.87+0.187 kg ai/ha, regardless of cover crop or residue level. Late season weed control for herbicide combinations were affected by cover crop and residue levels. In no cover crop residues, atrazine, metolachlor, mesotrione PRE at 0.7+1.87+0.187 kg ai/ha had the greatest suppression of predominant weed species smooth crabgrass. In low rye residue levels, glyphosate POST at 0.48 kg ai/ha had the greatest control. For low rye/vetch, higher rye, and higher rye/vetch residue levels, atrazine, metolachlor, mesotrione PRE at 0.35+0.935+0.935 kg ai/ha and glyphosate POST at 0.48 kg ai/ha provided the best control. Cover crop residues alone did not provide acceptable late season weed control, ranging from 64 to 94% smooth crabgrass cover. Cover crop residues without herbicide inputs had corn yields that ranged from 2,657 to 5,479 kg/ha.  In low rye, low rye/vetch, and higher rye/vetch, corn yields were highest with atrazine, simazine PRE at 2.24+2.24 kg ai/ha at 7,777, 9,151, and 10,120 kg/ha, respectively. In no rye and higher rye, atrazine, metolachlor, mesotrione PRE at 0.35+0.935+0.935 kg ai/ha and glyphosate POST at 0.48 kg ai/ha treatments had the highest corn yields at 7,786 and 8,895 kg/ha.  Generally, corn yields were higher with rye/vetch cover crops. Incorporating vetch into small grain cover crops seemed to increase average corn yields. Reducing PRE herbicide rates did not seem to reduce corn yields. Producers may have the option of reducing PRE herbicide rates in conjunction with late April desiccation of rye/vetch cover crops.                  

   Field studies were conducted in the fall of 2009 and 2010 in order to evaluate the response of eight newly seeded tall fescue cultivars to mesotrione applied at planting (PRE), and PRE followed by sequential treatment four weeks after turfgrass emergence (WAE) at rates ranging from 0.14 kg ai/ha to 1.125 kg ai/ha.  All applications were made with a single 9504EVS nozzle CO₂ pressured sprayer calibrated to deliver a total 178 L/ha at 222 kPa.  Experimental design was a strip plot (tall fescue cultivar x mesotrione application regime) with 4 replications.  Tall fescue cultivars ‘Rebel Advance,’ ‘Cochise II,’ ‘Hounddog,’ ‘Bullseye,’ ‘3^rd Millenium,’ ‘Faith,’ ‘Falcon V,’ and ‘Mustang IV’ were seeded on September 9, 2009 at a rate of 295 kg/ha in 1.8 m wide rows using a drop spreader.  PRE application was made on September 9, 2009 and PRE + 4 WAE on October 6, 2009.  Tall fescue was visually evaluated for cover and injury at 4 and 8 weeks after seeding, as well as in the springtime on a scale of 0 (no cover or injury) to 100 (complete cover or injury).   In this study, reductions in establishment were visible for some of the cultivars at 1.125 kg ai/ha applied PRE or PRE + 4 WAE.  The most severe reductions occurred in the PRE + 4 WAE were visible in cultivars ‘Rebel Advance’ and ‘Hounddog,’ with 17.2% and 20%, respectively.  There is some degree of intraspecific variability, with cultivars ‘Bullseye,’ ‘3^rd Millenium,’ ‘Faith,’ and ‘Mustang IV’ showing the most tolerance to 1.125 kg ai/ha applied twice while ‘Rebel Advance’ and ‘Hounddog’ were more sensitive.  The results of this study suggest that although differences in tolerance to mesotrione was observed in some cultivars, these differences were minor, suggesting that tall fescue cultivars should all respond similarly to mesotrione (Tenacity) applications.

   Producers, engineers, and biologists agree that weed control is the leading production problem in organic agriculture today.  Greenhouse, field, and laboratory studies were conducted in 2009 and 2010 at the University of Tennessee to design, build, and evaluate a tractor mounted system to apply cryogenic liquids for weed management in organic systems.  The incorporation of specialized technology including cryogenically tolerant hoses, a hydraulic nozzle delivery system, and a specialized insulated hood were designed in concert to facilitate an even spray application of liquid N₂ to target weeds.  Following liquid N₂ application a weighted roller located behind the sprayer hood was designed to crush the weeds within seconds after application in order to damage frozen cells of the plant before they thaw, thereby providing synergistic weed control over that observed with roller compaction or liquid N₂ applications performed separately.  Two field studies were conducted to evaluate the cryogenic sprayer with liquid N₂ being applied at 250, 500, and 1000 gal/acre rates on two sites primarily containing pitted morningglory (Ipomoea lacunosa).  In addition to application rate, sprayer height (placed 6 or 12 inches above the ground) and variations in pressure generated by the weighted roller (3 or 6 psi) were also evaluated as variables in improving performance of the cryogenic sprayer.  Herbicidal response was apparent almost instantaneously after application and by 1 day after treatment (DAT), burndown of the existing vegetation was most pronounced when liquid N₂ was applied at 1000 gal/acre.  Liquid N₂ applications were generally optimal with increasing rate, application height, and compaction pressure.  By 7 DAT, 1000 gal/acre of liquid N₂ applied at a spray height of 12 inches above the ground, followed by a compaction pressure of 6 psi provided 78 to 86% control of pitted morningglory.  Our paper presentation will attempt to explain the engineering techniques, biological trials, and design challenges associated with building and implementing this prototype.  In addition, this paper presentation will highlight the benefits of this technology as well as the limitations for commercial acceptance.

An infestation of Japanese knotweed (Polygonum cuspidatum Sieb. and Zucc.) at Milton State Park, Milton, PA, was subjected to treatments including two cuttings (May 6 and July 23, 2009), cutting (June 2) followed by application of glyphosate or triclopyr at 3.4 kg ae/ha (September 9), sequential treatment with glyphosate or triclopyr at 3.4 kg ae/ha on May 6 and September 9, or sequential treatment with glyphosate or triclopyr at 3.4 kg ae/ha on July 23 and September 9. The treatments were applied to 3.7 by 6.1 m plots arranged in a randomized complete block with three replications. The May 6 treatments were applied at a carrier volume of 750 L/ha to plots ranging from 15 to 45 percent cover, with stem heights ranging from emerging to 2 m. The July 23 and September 9 treatments were applied at a carrier volume of 1260 L/ha. The July treatments were applied to intact, 2 to 3 m tall canopies, while the September-treated plots were more variable, with canopy heights of 1 to 3 m and cover values of 15 to 100 percent. Canopy reduction was visually rated June 16, 2010, and a fresh weight harvest and stem count was taken September 24, 2010 from permanent 2.25 m² subplots, and converted to kg fresh wt/m². Data were subjected to analysis of variance and means separated using Fisher’s Protected L.S.D. test when treatment effects were significant.

Significant differences occurred between the herbicide treatments, but not between the treatment sequences for a given herbicide. The glyphosate treatments averaged between 97 and 98 percent canopy reduction, and were rated significantly higher than all other treatments. The triclopyr treatments ranged from 35 to 52 percent reduction, and were not significantly different from each other, and cutting twice resulted in a 20 percent canopy reduction. The untreated check averaged 1.8 kg fresh weight and the twice-cut plots averaged 3.4 kg. The glyphosate-treated plots yielded 0.02 to 0.18 kg/m², and the triclopyr-treated plots averaged 0.78 to 1.6 kg. Compared to the untreated plots, the glyphosate treatments reduced fresh weight biomass 90 to 99 percent, while the triclopyr treatments reduced fresh weight 11 to 56 percent. These data confirm results from a similar trial at this site in 2008. In that trial, suppression from glyphosate treatments was similar to 2009 results, and knotweed suppression was greater in glyphosate-treated plots than triclopyr-treated plots, but in 2008 the triclopyr treatments provided more suppression relative to the controls than in 2009.

   Japanese stiltgrass (Microstegium vimineum (Trin.) A. Camus) is an annual invasive grass native to Asia that is infesting riparian areas throughout the southeastern United States.  It is extremely shade tolerant and forms dense monocultures after invasion.  A study began in 2009 to evaluate herbicides that are registered or are pending registration for aquatic-use for Japanese stiltgrass control.  Herbicides were applied at various rates to natural stands of Microstegium vimineum  located alongside restored stream channels. Studies were performed to determine effectiveness of herbicides for both preemergence (PRE) and postemergence (POST) control.  The PRE study utilized five aquatic-use registered herbicides including carfentrazone, fluridone, imazamox, imazapyr, and penoxsulam and two aquatic-use registration pending herbicides of bispyribac and flumioxazin.  The POST study employed six aquatic-use registered herbicides including diquat, fluridone, glyphosate, imazamox, imazapyr, penoxsulam and two aquatic-use registration pending herbicides including bispyribac and flumioxazin.  Preliminary results indicated good PRE herbicide effectiveness with flumioxazin, fluridone, imazamox, and imazapyr. POST effective herbicides included flumioxazin, imazamox, and imazapyr. The study will continue in 2010 and preliminary data from 2009 will be discussed in this presentation.  

Indaziflam is a new alkylazine herbicide being developed for pre-emergence control of annual monocot and dicot weeds in industrial areas.  Indaziflam is a cellulose biosynthesis inhibitor (CBI) and represents a novel mode of action for bareground weed control.  The objective of this study was to determine the effectiveness of indaziflam for bareground weed control in a railroad bed.  A trial was conducted in Sanford, NC on an abandoned railroad spur.  Treatments included indaziflam 200SC applied alone (75 and 100 g ai/ha) and in tank mixtures (75 g ai/ha) with the following herbicides: Karmex (4483 g ai/ha), Oust Extra (150 g ai/ha), Krovar (7170 g ai/ha), Endurance (730 g ai/ha), Payload (286 g ai/ha), and Arsenal (821 g ai/ha).  The standards were also applied alone.  Glyphosate (2240 g ai/ha) was added to all treatments to control existing vegetation (30% cover).  Applications were made on April 6, 2010 with a conventional CO² backpack sprayer equipped with flat-fan nozzles at a spray volume of 25 GPA.  Bareground weed control and species composition were evaluated at monthly intervals through August 2010.

Weed pressure was very high due to heavy rainfall and previously low herbicide inputs.  At 2 months after treatment (MAT), indaziflam and indaziflam tank-mixes were giving >90% weed control, and Krovar (7170 g ai/ha) was the only standard that gave comparable control.  At 4 MAT, indaziflam alone was providing an average of 70% bareground with no differences between rates.  Combinations of indaziflam plus either Karmex, Oust Extra, Krovar, or Arsenal continued to provide above 90% control, whereas combinations with Payload and Endurance were less than 90% effective.  All standard herbicides with the exception of Krovar, provided significantly less bareground control than Indaziflam alone due to poor annual grass control, primarily large crabgrass (Digitaria sanguinalis).  Indaziflam gave good annual broadleaf weed control and was more effective than Payload or Endurance.  Indaziflam tank-mixes gave better broadleaf control than either herbicide applied alone.        

Indaziflam applied at 75 to 100 g (plus glyphosate) provided excellent, long-term control of annual grasses, good control of broadleaf weeds, and outperformed many of the standard herbicides.  Tank-mix combinations provided highly effective bareground weed control lasting at least 4 months.  Therefore, indaziflam shows great potential as an herbicide for bareground weed control in industrial settings, and more work is needed to design regional programs and tank-mixtures.

Mile-a-minute vine (MAM), also known as mile-a-minute weed, devil’s tearthumb or Asiatic tearthumb, has the botanical name of Persicaria perfoliata (L.) H. Gross (formerly Polygonum perfoliatum L.).  This herbaceous plant is indigenous to eastern Asia and has an annual life cycle.  MAM was introduced accidentally from China by a nursery in York County, PA in the 1930s.  By the 1990s, MAM was established in eight eastern states.  MAM is a serious invasive weed because it spreads rapidly in disturbed and natural habitats, where it can climb over and smother plants.  In Connecticut, MAM was first identified in 2000 at the southwestern corner of the state in Greenwich (Fairfield County).  Since then, MAM has spread to several other towns in Fairfield and Litchfield Counties.  Large stands of MAM were discovered in 2008 in North Haven (New Haven Co.) and in September 2010 in Sprague (New London Co.).  Many of these MAM sites are along rivers or streams, so herbicide use may not be feasible.

A small weevil (Rhinoncomimes latipes Korotyaev) native to China has high specificity for MAM as a host plant and was deemed an excellent biological control candidate by the U.S. Forest Service.  After extensive testing, these weevils were approved for field release by USDA-APHIS in 2004 and were released at MAM-infested sites in Delaware and New Jersey.  In subsequent years, weevils were released in Maryland, Pennsylvania and West Virginia.  In 2009, Connecticut joined a regional program with support from the Forest Service and USDA-APHIS for the first releases of R. latipes in New England.  This project is a collaboration between the University of Connecticut and The Connecticut Agricultural Experiment Station, following protocols established at the University of Delaware.  We received shipments of R. latipes weevils reared at a New Jersey Department of Agriculture laboratory.  Our objective is to evaluate R. latipes as a biocontrol agent for MAM in Connecticut.  In July 2009, we released a total of 7,000 weevils at seven MAM sites in the towns of Greenwich, Newtown, North Haven, Bridgewater and New Milford.  In May 2010, we released a total of 6,000 weevils at four properties in Stamford, Westport and Fairfield.

By the time weevils were released in 2009, MAM vine growth was extensive and some fruits were developing.  Thus, the relatively small number of weevils (1,000 per site) caused little overall damage to MAM that year.  However, feeding by adults resulted in many small holes in leaves.  Mating and egg laying occurred, and larval tunneling into MAM stems was observed.  A second generation of adults developed in late summer 2009.  Most weevils survived the winter of 2009-10, and at sites in North Haven and Newtown, they survived extensive flooding in March 2010.  Overwintering (or newly released) weevils began feeding early in the 2010 growing season, thus damage to MAM was more extensive.  Three or more generations of weevils were produced in 2010, and some dispersed to MAM several hundred yards from release sites.  No weevil damage was observed on native plants, including arrow-leaved tearthumb (Polygonum sagittatum) and other Polygonum species.  Depending on R. latipes availability in 2011, we plan to release weevils at other MAM sites in CT.

The Asiatic sand sedge (Carex kobomugi) is an invasive plant that is expanding rapidly on coastal dunes throughout eastern North America. This species outcompetes native vegetation, reducing the abundance and diversity of native plants within these habitats. It also changes the suitability of invaded dunes as habitats for native animals, including endangered species such as the piping plover (Charadrius melodus). Because of its lower stature relative to the dominant native dune species, it collects sand differently, so the invasion even changes the profile of invaded dunes. As a consequence of the severe ecosystem damage, environmental managers are increasingly realizing the need to control the spread of this species and to remove it from habitats that have already been invaded. The goal of this project was to determine the effectiveness of a variety of chemical control methods for C. kobomugi. In our first experiment glyphosphate (Accord Concentrate at 2% v/v, equivalent to approximately 0.5 gal/A), and five different rates of imazapic (4, 6, 8, 10 and 12 fl.oz./A of Plateau) were applied to three replicate plots each within a relatively homogenous population of C. kobomugi in September 2009. In our second experiment three replicate applications of each of glyphosphate (Accord Concentrate at 2% v/v, approximately 0.5 gal/A), imazapic (Plateau at 12 fl.oz./A) and halosulfuron (Sedgehammer at 1.3 oz/A) were applied to three replicate plots each within the same population in May 2010. The number of surviving plants was determined using stem counts within three, one m² quadrats within each plot, and the resulting mean was compared to control plots to which a solution of the surfactant, colorant and water, but no active herbicide, had been applied. Both Accord Concentrate and Plateau resulted in significant reductions in sedge survival relative to the control. There was no significant difference between the number of plants surviving in plots treated with Accord Concentrate or Plateau, or between plots receiving different concentrations of Plateau. However, qualitatively, Accord Concentrate performed better than Plateau, and intermediate concentrations of Plateau resulted in lower numbers of surviving sedge than did the lowest and highest application rates. In our second experiment, significant declines in sedge survival were seen with Plateau, but Sedgehammer and Accord Concentrate did not result in significantly lower survival of the sedge relative to the control. However, the second experiment was performed very early in the season, and a rainstorm occurred soon after applications, so these results may not be reflective of the true effectiveness of these products. We are currently repeating the second experiment and will report the results during our presentation if available. We conclude that both imazapic and glyphosphate significantly reduce the survival of Carex kobomugi. However, neither product completely eliminates the species in a single application. The effectiveness of halosulfuron for the control of this species is unclear.

   Pale swallow-wort [PSW] (Vincetoxicum rossicum) is an invasive non-native perennial vine that is increasing in many regions of the NE U.S. and southern Canada. It thrives in old fields but can also establish in shaded forest understories. Control of PSW has been difficult and limited information is available on the efficacy of herbicides for its control. We conducted a 2-yr (2008/09) herbicide and clipping study in an old field (OF) and adjacent forest understory (FU) site near Ithaca, NY. We compared 7 treatments on PSW stem density and percent cover in these habitats. Treatment plots were 4 x 4 m and vegetation in all plots was mowed to a 5 cm height in mid-June of both years. There were 7 replicate plots for each treatment (49 plots total/ habitat). The 7 treatments were: (1) glyphosate (Roundup Pro^®) at 4.87 & 2.44 kg ai/ha in OF and FU, respectively; (2) triclopyr triethylamine salt (Brush-B-Gone^®) at 0.93 & 0.46 kg ai/ha in OF and FU; (3) triclopyr triethylamine salt  (Garlon^®3A) at 4.87 & 1.70 kg ai/ha in OF and FU; (4) triclopyr butoxyethyl ester (Garlon^®4 Ultra) at 2.99 & 0.43 kg ai/ha in OF and FU; (5) triclopyr butoxyethyl ester (Garlon^®4 Ultra) at 4.87 & 2.27 kg ai/ha in OF and FU; (6) an untreated check; and (7) a second mowing at the time of herbicide application. Pre-treatment assessments of PSW stem number and percent cover, in a 1 x 1m sub-plot, were made a few days prior to mowing (mid-June). Herbicides were applied in late August with a CO₂ back-pack sprayer pressurized at 100 kPa. Post-treatment measurements for 2008 & 2009 applications were made in mid-June 2009 and 2010, respectively. By mid-June 2010, treatment effects differed in the two habitats. In the OF, the highest reductions in cover relative to pre-treatment levels were observed for the triclopyr butoxyethyl (Garlon^®4 Ultra– 4.87 kg/ha) (84%) and glyphosate-treated plots (77%). Mowing plots twice in 2008 and 2009 resulted in a 301% increase in PSW cover. The density of large (>5cm) PSW stems declined by 86% in triclopyr triethylamine (Garlon^®3A– 4.87 kg/ha) and triclopyr butoxlyethyl (4.87 kg/ha)-treated plots. Large stem density increased by 73% in mowed plots. Small (<5cm) stem density decreased in all treatments, with the greatest decline (96%) in plots treated with triclopyr triethylamine at 4.87 kg/ha. In the FU, cover was reduced in all treatments including mowed plots (20%). The highest reductions were achieved in the glyphosate (80%) and triclopyr triethylamine (78%) (1.70 kg/ha)-treated plots. Large stem density decreased in all FU treatments, with the largest decrease (91%) occurring in triclopyr triethylamine (1.70 kg/ha)-treated plots. The greatest decline in small stem density (37%) occurred in plots treated with triclopyr butoxyethyl at 2.27 kg/ha. The density of small stems increased by 77% in triclopyr triethylamine (Brush-B-Gone^®– 0.46 kg/ha)-treated plots and by 36% in triclopyr butoxyethyl (0.43 kg/ha)-treated plots. Findings suggest that management of PSW using herbicides in combination with mowing can be effective but may vary with habitat. Land managers should consider these possible differences to ensure successful control of this vine.

   Bayer seed and trait business enjoys a rich research pipeline and a strong market position in its core market areas of oilseeds, cotton, rice and vegetables while working to expand in wheat, soybean, sugarcane, and corn markets. Bayer has an internationally renowned and comprehensive intellectual property portfolio as well as highly expert personnel who are committed to ensuring a responsible and effective use of our products and technologies.

   In the lab, effort is focused on the development of traits for improved yield, improved quality, and limiting abiotic and biotic stress impacts on the crop. In the field, Bayer has developed and commercialized the LibertyLink trait technology for corn, soybean, which provides an alternative herbicide tolerant trait technology for Integrated Weed Management in addition to other traits in the core markets. Bayer has broadly licensed its soybean and corn trait technology to the seed industry.

   Bayer continues its focus on Integrated Weed Management with trait development in soybean and corn. Bayer, in collaboration with M.S. Technologies, is working to bring soybean varieties to the market tolerant to both glyphosate and to HPPD inhibitors.

   The growing global demand for food, feed and fuel will require increased yields per acre of land. Effective, integrated weed control systems are key to help farmers meet this growing demand. The addition of dicamba tolerance to the Genuity™ Roundup Ready 2 Yield™ Soybean platform will offer growers an additional tool for flexible and effective weed management along with the increased yield opportunity of Roundup Ready 2 Yield. Once approved, the dicamba tolerant technology will enable the use of dicamba and glyphosate tank-mixes for preplant burndown, at planting, and in-season applications adding considerable weed control value to the well-established and effective Roundup Ready® system.

   Dicamba is an economical herbicide that controls a broad spectrum of broadleaf weed species including those tough-to-control and/or resistant to ALS chemistry and glyphosate.  Farmers have successfully used dicamba for decades in crops such as corn and wheat with few cases of documented weed resistance in the U.S. Dicamba tolerant soybeans will not be a stand alone weed control solution but will be part of an agronomically sound weed management system. Monsanto has been working with a group of academics over the past years to develop regionalized weed management systems for Dicamba tolerant soybeans.  Early data demonstrate effective season-long weed control from an integrated approach that includes the use of residual components and different herbicide mode of actions.

   To help guide research efforts and address concerns with the launch of this trait, Monsanto has formed a Dicamba Advisory Council. The role of this council is to provide stakeholder input into the development of appropriate stewardship measures and weed control systems for this trait. Furthermore, extensive research programs have been initiated to identify appropriate application systems that address concerns regarding potential off-target movement of dicamba chemistry. Monsanto and BASF agreed to accelerate the development of innovative formulations for dicamba for use with herbicide-tolerant cropping systems. Both companies are working together to develop robust Best Management Practices for the use of dicamba over Dicamba tolerant soybeans allowing farmers to fully realize the benefits of this dual stacked herbicide tolerant weed control system in soybean.

   The Dicamba tolerant soybean project is in the Phase III stage of Monsanto’s research and development pipeline. Regulatory submission to the U. S. Department of Agriculture was made in July of 2010; submissions to the U.S. Food and Drug Administration and key global markets are anticipated to follow shortly. Dicamba tolerant soybeans are projected to be commercialized in the middle of this decade, pending global regulatory approvals with initial product launches in the U.S. and Canada.

   Dow AgroSciences Herbicide Tolerant (DHT) Trait Technology confers robust tolerance to the herbicide 2,4-D in corn, cotton and soybeans.  The technology offering will also provide tolerance to glufosinate in soybeans and cotton and the FOP class of grass herbicides in corn.  DHT will be stacked with other herbicide tolerance traits such as glyphosate tolerance to provide users a diverse and more complete herbicide system.  By incorporating multiple classes of herbicides, the efficacy against glyphosate-resistant and hard-to-control weeds, such as: morningglory, pigweed (including Palmer amaranth), giant and common ragweed, lambsquarters, marestail, waterhemp and velvetleaf, will be greater than a single mode of action herbicide system.  By managing these hard-to-control weeds with multiple modes of action, the DHT trait technology will help sustain the widely adopted glyphosate cropping system that helps make farming easier, more affordable and more environmentally beneficial.

   Along with the DHT trait technology, Dow AgroSciences is investing in research and development of novel 2,4-D herbicide technology.  This technology will be specifically designed and authorized for use over-the-top of crops containing the DHT trait to deliver high levels of broad spectrum performance which align with Dow AgroSciences’ significant commitments to the stewardship of the technology.  One aspect for this research is focused on improving safety to adjacent, sensitive crops by decreasing volatility and reducing drift.  Dow AgroSciences will provide a comprehensive stewardship program that will maintain the long-term viability of the DHT system.

   During the period since the introduction of glyphosate resistant crops, the number of weedy plant species that have evolved resistance to glyphosate has increased dramatically from zero in 1995 to 19 in June of 2010.  A recent National Research Council report (http://www.nap.edu/catalog.php?record_id=12804) lists at least nine species of weeds resistant to glyphosate in the US, largely because of repeated exposure to glyphosate. Italian ryegrass, horseweed, Johnsongrass, common and giant ragweed, Palmer amaranth, and common waterhemp are the confirmed glyphosate resistant weed problems of today.  Here in Pennsylvania and in most of the Northeast, setting aside some of the older resistance problems of the past (e.g. triazines, etc.) and focusing on glyphosate, we have been lucky thus far and are “only” dealing with glyphosate resistant horseweed and scattered populations of glyphosate-resistant common ragweed and suspected problems with common lambsquarters.  But, where is the future of weed control in corn, soybean, and other northeastern crops heading if we continue to select for more glyphosate resistant and tolerant weeds? Do these glyphosate resistant weeds mean a return to using older products like bentazon, lactofen, acifluorfen, and 2,4-DB in soybean?  Or will the latest transgenic technology currently being tested in regulated experiments across the US corn belt (DHT, dicamba resistance, and GAT) and being presented and discussed today nip this problem in the bud or at least delay the useful demise of  glyphosate and other currently valuable chemistry?  It’s never been more clear to us that the need to identify and develop integrated weed management programs that emphasize herbicide rotation and effective tank mixes in combination with nonchemical management strategies is critical for preserving the technology we have become so dependent on, but how do we achieve this goal? Voluntary adoption of good stewardship practices is a hard sell, but regulating herbicide use is controversial and opposition to this idea is widespread.  These are discussions our scientific community must continue having, but time is short.

   During 2008 and 2009, the IR-4 Ornamental Horticulture Program tested twelve pre-emergent herbicides across the United States to determine whether they had potential use in controlling emerged weeds at the cotyledon to 1 leaf or 2 to 4 leaf stage. Three troublesome weeds were targeted including bittercress (Cardamine hirsuta), oxalis (Oxalis stricta), and spurge (Euphorbia humistrata). Bittercress was controlled at the early postemergence application timings with Certainty (sulfosulfuron) at 0.035 to 0.094 lb ai/A, EXC3898 at 2.1 to 3.1 lb ai/A, and Gallery 75 DF (isoxaben) at 1.0 lb ai/A. Spurge control at early postemergence was demonstrated with 4.0 lb ai/A of Pendulum (pendimethalin). Emerged oxalis seedlings showed significant impact from Broadstar VC1604 at 0.375 lb ai/A and V-10142 at 0.38 to 0.75 lb ai/A; however, the impacts from these products were inconsistent and additional research on several other products is needed. Limited experiments including Broadstar 0.25G, Casoron, Freehand, HGH-63, and Tower showed promise on at least one weed species.

   In earlier work (Proc. NEWSS 57:36) we found that container-grown bigleaf hydrangea (Hydrangea macrophylla ‘Merritts Supreme’) were sensitive to sprays of isoxaben alone or in combination with dinitroaniline herbicides.  This work showed that sprays of diuron at 0.25 lb/A were less injurious than isoxaben to bigleaf hydrangea. In a 2010 experiment we tested again the effects of diuron sprays and also a newer herbicide, dimethenamid-p (Tower), on three macrophylla varieties.  The hydrangeas were potted on June 7, 2010 into 1-gal containers, with a mix of 70% bark, 15% sand and 15% peat.  The three hydrangea varieties were ‘Big Daddy’, ‘Penny Mac’ and ‘Endless Summer’. Three containers of each variety and six plantless containers were in each plot and the treatments were replicated four times in randomized complete blocks. The herbicides were applied with a 2-nozzle hand-held boom and 8004 tips, applying 50 gal/A at 3 ft/second, first on June 10. The hydrangea foliage, at treatment, was wet and some plants showed chlorosis. After applying the herbicide sprays, which took 40 minutes, the plants were irrigated for 20 minutes. Seeds of groundsel (Senecio vulgaris) and large crabgrass (Digitaria sanguinalis) were sown in treated plantless containers on June 17. Diuron 80W was applied at 0.25, 0.5 and 1.0 lb ai/A and, in combination with oryzalin 4AS, at 0.25 + 2 and 0.5 + 4 lb ai/A, and with prodiamine 65WG at 0.25 + 1 and 0.5 + 2 lb ai/A.  The standard comparisons included in the experiment, that are used on most plants at Imperial Nurseries, were isoxaben 75DF + oryzalin AS at 1 + 2 lb ai/A and isoxaben 75DF + prodiamine 65WG at 1 + 1 lb ai/A.  Dimethenamid-p was applied at 1, 2 and 4 lb ai/A. The second treatment, of dimethenamid-p only, was applied on pre-wetted foliage on July 3 and the plants were irrigated for 20 minutes immediately after application. 

   All of the diruon treatments, alone or in combination, caused excessive injury to the bigleaf hydrangeas after one application and were not treated a second time. Note that the hydrangea varieties differed from the variety tested in the earlier work. Dimethenamid-p at the lowest rate (1 lb ai/A) caused commercially acceptable injury to all three varieties and differences in dosage of dimethenamid-p did not appear to be important. Dimethenamid-p at 1 lb ai/A gave 95% control of large crabgrass and 90% control of common groundsel. This experiment indicates that further research with dimethenamid-p is warranted in container-grown bigleaf hydrangea.

   In previous experiments, mesotrione and a three-way combination of glyphosate (Roundup Original) plus oxyfluorfen (Goal Tender) plus clopyralid (Lontrel, Stinger) controlled many annual broadleaf weeds and grasses and proved non-injurious to ten actively-growing conifers grown as nursery plants or Christmas trees (Proceedings NEWSS vol. 62, 63, 64).  In one experiment in 2010, on a sandy loam soil in Windsor, CT, these herbicides were applied for a third year on the same ten conifers.  The plants were eastern white pine (Pinus strobus), Fraser fir (Abies fraseri), Douglas-fir (Pseudotsuga menziesii), Norway spruce (Picea abies), white spruce (Picea glauca), Colorado spruce (Picea pungens), eastern hemlock (Tsuga canadensis), American arborvitae (Thuja occidentalis), Japanese yew (Taxus media ‘Hicksii’) and juniper (Juniperus horizontalis ‘Blue Star’).  All were actively growing at treatment.  The herbicides were applied over-the-top in 25 gal/A with a four-nozzle hand-held boom and 8003-VS nozzles, on May 27 and repeated on July 1.  Mesotrione 4SC was applied at 0.1875, 0.5 and 0.75 lb ai/A.  The three-way combination of glyphosate plus oxyfluorfen plus clopyralid was applied at 0.125+0.25+0.094 lb ai/A and double these rates.  Treatments were replicated four times in randomized complete blocks.  No significant injury to any of the ten conifers was observed with any of these treatments.

   In Enfield, CT, on a silt loam soil, mesotrione was applied on June 2 and again on July 8, at 0.125, 0.1875, 0.5 and 0.75 lb ai/A, over actively-growing Fraser firs for a second year.  Treatments were replicated four times in plots of six plants each.  No injury to the firs was observed.

   In a third experiment, adjacent to the one above, Fraser firs planted in April 2010 were treated with mesotrione at the above rates with and without fluazifop-p-butyl (Fusilade DX) at rates of 0.25, 0.375, and 0.5 lb ai/A plus 0.25% NIS, when green foxtail (Setaria viridis) was 6 to 8 in tall on June 16 and again on July 22.  Treatments were replicated four times in randomized complete blocks on plots, each with ten plants.  None of the treatments injured the firs.  Mesotrione alone did not control green foxtail but combinations of mesotrione with fluazifop-p-butyl gave complete control.  It appears that the addition of fluazifop-p-butyl to mesotrione could improve control of grasses not controlled by mesotrione alone, without injury to actively-growing conifers.

   Dimethenamid-P was registered in 2008 as a preemergence herbicide for ornamental uses including commercial field and container production and non-turfgrass landscape areas.  Both a liquid EC dimethenamid-p (720 g/L) formulation and the dimethenamid-P + pendimethalin granular formulation (1.75%) are registered for over-the-top applications in nursery production and landscape sites.  Previously, IR-4 researchers reported pendimathalin 2 G to have broad tolerance to herbaceous annuals and perennial ornamental plants. Pendimethalin is one of the components in the 1.75% GR dimethenamid-P based product. Also, these same reports show metolachlor EC formulation has less plant tolerance when applied to herbaceous plants. Metolachlor and dimethenamid-P preemergence herbicides are both chloroacetamide Group 15 herbicides. Research objectives in 2009-2010 focused on dimethenamid-P use in landscape maintenance and plant tolerance of herbaceous plants.

   Roll-crimped cover crops have received recent attention as a possible means of reducing tillage in organic cropping systems.  Beginning in 2008, multiple experiments were conducted on the agronomic and weed management impacts of roll-crimped cover crop mulches.  Level of weed control was highly dependent on the amount of cover crop biomass.  Percent yield loss due to weeds in soybean ranged from 0% with high rye biomass to greater than 80% reduction with low rye biomass.  In the case of corn, mixed legume/rye mixtures outperformed straight legume plots in terms of both weed control and yield.  While nitrogen contribution from the legumes was substantial, supplementation will likely be necessary in most years.  Overall, both the rye/soybean and legume/corn system can reduce expenses for organic farmers but the long-term yield advantage or disadvantage to the system is still to be determined.

Pendimethalin is the current preferred herbicide for selective PRE suppression of Japanese stiltgrass (Microstegium vimineum (Trin.) A. Camus var. imberbe (Nees) Honda) in park and natural areas due to efficacy, minimal impact to established non-target species, and history of use and manufacturer technical support.  Pendimethalin is not effective when seed germination has occurred, and is not labeled for use in wetland settings.  The impending introduction of flumioxazin and bispyribac-sodium with aquatic labels and increasing infestation of stiltgrass and jointhead arthraxon (Arthraxon hispidus (Thunb.) Makino) in a seasonally wet meadow at Waterloo Mills Preserve in Devon, PA provided a setting to test pendimethalin and other herbicides against a new, C4 annual grass target.  A second site at French Creek State Park, Elverson, PA was also used because it featured mile-a-minute (Polygonum perfoliatum L.) in addition to stiltgrass. The applications were delayed to test the utility of adding low rates of imazapic to strictly preemergence herbicides to determine if the application window could be extended while maintaining selectivity.  The April 1, 2010 treatments at Devon included pendimethalin at 2.1 kg/ha, and 4.3 kg/ha alone and in combination with imazapic at 0.018 kg/ha, prodiamine at 0.82 and 1.6 kg/ha, flumioxazin at 0.29 and 0.43 kg/ha, imazapic at 0.035 and 0.070 kg/ha, and bispyribac-sodium at 0.056 and 0.11 kg/ha.  The Elverson treatments were applied April 9, 2010 and included pendimethalin at 4.5 kg/ha alone, and in combination with imazapic at 0.018 or 0.035 kg/ha, prodiamine at 1.6 kg/ha alone or with 0.018 kg/ha imazapic, oryzalin at 4.5 kg/ha alone or with 0.018 kg/ha imazapic, and flumioxazin at 0.29 or 0.43 kg/ha.

When rated August 27, 2010, vegetative cover at Devon averaged 87 percent, and stiltgrass cover averaged 32 percent in the control plots.  Pendimethalin plus imazapic, prodiamine plus imazapic, and flumioxazin-treated plots averaged 1 percent or less stiltgrass cover.  Arthraxon density was sporadic, and averaged only 2 percent in the control, with a maximum of 13 and 15 percent in the bispyribac-sodium-treated plots.  There was no Arthraxon observed in plots treated with pendimethalin, alone or with imazapic, and flumioxazin.  Prominent non-target species at Devon included several goldenrods (Solidago spp.), crabapple (Malus spp.), soft rush (Juncus effusus L.), and mountain mint (Pycnanthemum virginianum (L.) Duran & Jacks. ex B.L. Rob. & Fernald).  Flumioxazin caused transient contact injury to all emerged species that were obscured by new growth by 33 DAT.  Imazapic caused significant injury to soft rush, even at the 0.018 kg/ha rate, and the higher rates injured the undesirable reed canarygrass (Phalaris arundinacea L.) as well.  At Elverson, except for short-term flumioxazin burn, significant injury was not observed on prominent non-target species, which included goldenrods, deertongue (Dicanthelium clandestinum (L.) Gould), briars (Rubus spp.), grapes (Vitis spp.), and poison ivy (Toxicodendron radicans (L.) Kuntze).  Total vegetative and stiltgrass cover averaged 98 and 70 percent in the control plots August 27, 2010.  All herbicide treatments reduced stiltgrass cover to 20 percent or less, with pendimethalin plus imazapic, flumioxazin, and oryzalin plus imazapic-treated plots averaging 5 percent or less stiltgrass cover.  Mile-a-minute seedlings were present at low densities in all plots at 0 DAT, but observed only in the controls on August 27.

   Mettler’s Woods, a 26 ha old growth forest, is the only uncut upland forest in New Jersey (Buell 1957).  The woods were sampled by Bard (1952) who identified one hundred twelve vascular plant species of which five were non-native to the region.  The objective of this study was to identify the non-native plant species at Mettler’s Woods during the spring 2010 growing season and to compare these species with those present at the site in 1951 at the conclusion of Bard’s study.  Non-native species have increased from 5 taxa, 4.45% of the flora in 1951 to 11 species, 14.3% of the flora in 2010.

INTRODUCTION

   Mettler’s Woods is an old growth climax forest composing 26 ha in Somerset County, New Jersey 40.5081595 N Latitude, 74.5426554 W Longitude.  This forest is one of the last uncut stands of old growth forest in the United States, and the only uncut upland forest in New Jersey (Buell 1957).  The average age of the forest is 235 years though annual ring counts on several trees that died within the past twenty years attained an age of over 350 years.  Bard (1952) reported that there were, “Fewer non-indigenous species at Mettler’s Woods than were present in nearby successional fields, aged 1-60 years.”  Bard (1952) concluded that Mettler’s Woods was a “closed community.” and that it was, “impossible for the alien species to enter in competition with the long established native vegetation.”  The primary objective of this study was to compare non-native vascular plant species present at Mettler’s Woods during the spring 2010 growing season with those present when Bard (1952) conducted her study at the site in 1949-1951.  A second objective was to determine the time aggressive, invasive, non-native vascular plant species invaded Mettler’s Woods by examining voucher specimens in the Chrysler Herbarium, Rutgers University (Table 2).  A third future objective will be to prepare a floristic inventory of Mettler’s Woods and to compare the vascular plant species present in 2010-2011 with those present at Mettler’s Woods in 1949-1951. 

METHODS

   Three collecting trips were made to Mettler’s Woods from April 17 to June 10, 2010.  Objectives for each trip included collecting voucher specimens and accumulating information on abundance and habitat preference for each species.  More than 100 specimens were the basis for this study.  Taxonomically problem species were sent to various experts for identification.  Gleason and Cronquist (1991) was consulted to determine to native status of each taxon.  Bard’s (1952) dissertation was consulted to determine which non-native taxa were collected by her during 1949-1951.  A comparison of the number and percentage of non-native taxa present at Mettler’s Woods during the 1949-1951 and spring 2010 collecting season is presented in Table 1.  The number and percentage of non-native vascular plant species in Bard’s (1952) Successional Fields and Mettler’s Woods and the spring 2010 collecting season are presented in Table 2.  Nomenclature follows Gleason and Cronquist (1991).

RESULTS AND DISCUSSION

   Bard (1952) reported 112 vascular plant species at Mettler’s Woods of which 5 were non-native, 4.46% of the total.  A preliminary survey of the site during the spring 2010 included 77 species, of which 11, 14.3% of the total, were non-native (Table 2). Notable among the aggressive alien invasives since Bard (1952) completed her study were: Alliaria petiolata, Celastrus orbiculatus, Microstegium vimineum, and Rosa multiflora.  An additional abundant invasive, Lonicera japonica, was present at Mettler’s Woods when Bard (1952) sampled the area in 1949-1951.  Berberis thunbergii and B. vulgaris, two common shrubby aliens at the woods in the past, have been monitored, and when encountered, eliminated from the site by Rutgers University scientists.

   The seeds of Alliaria petiolata and Microstegium vimineum may have been transported to Mettler’s Woods epizocally in soil adhering to the feet fur and feathers of birds and small mammals while the seeds of Celastrus orbiculatus, L. japonica and R. multiflora may have been initially transported endozoically by birds and perhaps later by certain mammals.  Germination of the seeds of these taxa may have been enhanced by ingestion as Krefting and Roe (1949) demonstrated that seed germination of certain plant species was enhanced after consumption by birds and mammals. 

   Survival and growth of invasive vascular plant species may be encouraged by disturbances that create gaps in the forest.  Disturbance events in Mettler’s Woods are browsing by white tail deer, wind throw during hurricanes, severe nor-easters, wind generation by passage of strong cold fronts, and defoliation outbreaks of gypsy moth infestation. Stalter and Serraro (1983) reported that oaks on mesic sites at the Greenbrook  Sanctury, New Jersey, were more susceptible to severe gypsy moth infestation than those occupying sites where moisture conditions were less favorable. Death of old Mettler’s Woods trees have created gaps in the forest that may have favored light-loving alien taxa such as Celastrus orbiculatus, L. japonica and R. multiflora.

                                            LITERATURE   CITED

1.     Bard, G.E. 1952. Secondary succession on the piedmont of New Jersey. Ecol. Monogr. 22: 195-215.

2.     Buell, M.F. 1957. The William L. Hutcheson Memorial Forest Bulletin, Dedication Issue. The Department of Botany, Rutgers.  42 pp.

3.     Gleason, H. A. and A. Cronquist, 1991. Manual of Vascular plats of Northeastern United States and Adjacent Canada. New York Botanical Garden, New York. 910 pp.

4.     Krefting, L.W. and Roe, E.L. 1949. The role of some birds and mammals in seed germination. Ecol. Monogr. 19: 269-286.

5.     Stalter, R. and Serraro, J. 1983. The impact of defoliation of gypsy moths on the oak forest at Greenbrook Sanctuary, New Jersey. Bull. Torrey Botanical Club.  110: 526-529.

Table 1. Number and percentage of non-native and native vascular plant species on abandoned fields of diverse ages and in Mettler’s Woods (MW), Somerset County, New Jersey. Data from Bard (1952) and from the present study, 2010.

Age of Field (yrs)                           Number of Non-native species       Total Number of Species  %Non-native Species

1                                                                         26                                                   92                             28.26

2                                                                         28                                                   102                            27.45

5                                                                         20                                                   93                             21.50

10                                                                       13                                                   92                             14.13

15                                                                       18                                                   97                             18.55

25                                                                       22                                                   105                            20.95

40                                                                       22                                                   123                            17.88

60                                                                       17                                                   105                            16.19

M.W. (1951)                                                       5                                                     112                            4.46

M.W. (2010)                                                       11                                                   77                             14.29

Table 2. Chrysler Herbarium acquisition data form aggressive non-native vascular plant species, Mettler’s Woods, NJ

Species                                                                             Acquisition Data

Ailanthus altissima                                                                     1960

Alliaria petiolata                                                                          1990

Berberis thunbergii                                                                     1949

Berberis vulgaris                                                                        1960   

Celastrus orbiculatus                                                                 1960

Lonicera japonica                                                                       1960

Lonicera morrowii                                                                       1960

Microstegium vimineum                                          None- Somerset County, 1959

Rosa multiflora                                                                            1967

   Mugwort (Artemisia vulgaris) is a perennial in the Asteraceae family that was introduced to North America from its native Europe. In Europe, it is abundant along roadsides, field margins, fences, and non-crop areas, and occurs in perennial and annual crops especially in reduced tillage fields. In North America, A. vulgaris is abundant in nurseries, turfgrass, on roadsides and waste areas. It causes crop yield reductions and reduces the quality of crops and habitats. Moreover, pollen from this species causes seasonal allergies in some people. A. vulgaris typically flowers the second year after establishment from seeds. In Europe, A. vulgaris propagates mostly by seeds and single plants can produce 50,000-70,0000 seeds.  The rootstock (rhizome) is short and thickened and new plants are usually formed if it is cut (e.g. by cultivation). North American studies show that A. vulgaris propagates primarily by an extensive rhizome system, while seed propagation is less important due to the production of few viable seeds. North American populations have been observed to be shorter, germinate earlier, have more ramets and greater belowground dry weight than European populations. These apparent differences will greatly affect the management of A. vulgaris. If seed production is an important feature of reproduction, then seed production should be curtailed. However, it is also important to remove the seed-producing plants. In populations that reproduce primarily via rhizomes, then plants should be removed and/or weakened. In Europe, it is relatively easy to control A. vulgaris with herbicides or plowing in arable crops, while this is more difficult in non-crop areas. A resource allocation study performed from spring to the initiation of flowering in Northern Europe showed a general increase in aboveground biomass during this period. In contrast, belowground biomass was reduced at the large rosette stage, at early stem elongation, and maybe during the last assessment, at the beginning of flowering. These stages may indicate a change in the directional flow of assimilates, and suggest when control efforts should be implemented. Interestingly, there were no differences in control when herbicides were applied in the late vegetative or the early flowering phase in a North American study.  Experience from Northern Europe suggests that to prevent flowering, mowing should be performed at least twice during the growing season. Another option for smaller infestations, with a more concentrated root/ rhizome system than in North America, is to pull up the plant by hand before flowering. However, the most effective method of controlling A. vulgaris in non-crop areas still needs to be determined in Europe. North American research shows effective long term control of this species using the herbicides picloram, clopyralid, and large dose rates of glyphosate. Mowing prior to use of herbicides does not necessarily provide more effective control compared with not mowing.

   A study to assess the effects of preemergence herbicides on wild blueberry cover, phytotoxicity and broadleaf and grass weed cover was conducted in spring/summer 2010 using an RCBD design with 6 replications: a check, hexazinone (2 lb ai/gal) 6 pt/A, hexazinone (2.4 lb ai/gal) 4.8 pt/A, hexazinone (2.4 lb ai/gal) 4.8 pt/A + surfactant 1 qt/A, indaziflam at 5 or 10 oz/A, terbacil WP 2 lb/A, terbacil WDG 2 lb/A, terbacil WDG 2 lb/A + mesotrione 6 oz/A, pendimethalin 6.3 qt/A, and rimsulfuron 4 oz/A were applied on 11 May 2010. Plots were evaluated at 1, 2, 4, and 8 weeks after treatment (WAT) and were analyzed using a nonparametric median two-sample exact test with α=0.05. Treatments were compared individually to the check, to the standard hexazinone (2 lb ai/gal), and to each other where relevant. Hexazinone (2.4 lb ai/gal) significantly reduced broadleaf weeds in comparison to the check and did not injure wild blueberry. Hexazinone (2.4 lb ai/gal) resulted in lower grass cover than hexazinone (2 lb ai/gal) at 1 WAT only. Addition of the surfactant resulted in a non-significant reduction of blueberry cover over time and a non-significant increase in broadleaf weeds and grass by 8 WAT. The indaziflam 10 oz/A treatment had significantly lower blueberry cover at 1, 2, and 8 WAT compared to the check and at 1 and 8 WAT compared to hexazinone (2 lb ai/gal). Both indaziflam treatments had significantly reduced broadleaf weed cover compared to the check by 8 WAT, while indaziflam 10 oz/A was lower than hexazinone (2 lb ai/gal) at 1 WAT only. The indaziflam treatments also resulted in significantly lower grass cover than hexazinone (2 lb ai/gal) by 8 WAT. There was higher blueberry phytotoxicity in the indaziflam 10 oz/A treatment than the check or the 5 oz/a treatment at 4 WAT, but lower phytotoxicity than the 10 oz/A postemergence treatment at 2, 4, and 8 WAT. All terbacil treatments resulted in comparable blueberry cover compared to no treatment or hexazinone (2 lb ai/gal), as well as negligible phytotoxicity. Terbacil WDG, alone and with mesotrione, significantly suppressed broadleaf weeds by 8 WAT compared to no treatment. All terbacil treatments significantly reduced grass cover compared to hexazinone (2 lb ai/gal) at 4 and 8 WAT. Tank-mixing terbacil WDG with mesotrione did not significantly improve broadleaf weed or grass control compared to terbacil WDG alone. Terbacil WDG had significantly more blueberry cover than terbacil WP at 4 WAT and significantly less broadleaf weed cover than terbacil WP at 4 and 8 WAT. Otherwise, there were no significant differences in any cover or phytotoxicity for terbacil WDG versus terbacil WP or terbacil WDG + mesotrione. There were no significant differences between rimsulfuron and the check or hexazinone (2 lb ai/gal) for blueberry cover or phytotoxicity. At 4 WAT there was significant phytotoxicity in the pendimethalin treatment, which resulted in significantly lower blueberry cover than the check or hexazinone (2 lb ai/gal) at 8 WAT. Pendimethalin significantly reduced broadleaf weeds by 8WAT compared to the check. Grass cover in the pendimethalin treatment was significantly lower than hexazinone (2 lb ai/gal) by 8 WAT, and rimsulfuron had lower grass cover at 4 and 8 WAT.

   Flame cultivation is a nonchemical method of weed control where target plants are damaged or eradicated by brief exposure to high temperature.  The utility of flame cultivation on perennial weeds in cranberry systems is currently being investigated to determine if it could be a useful practice for weed control. Two problematic cranberry weeds are the herbaceous perennial, soft rush (Juncus effusus), and the woody perennial, dewberry (Rubus spp.).

   Alion is a preemergence herbicide based on the new active ingredient indaziflam that Bayer CropScience has developed for use in perennial fruit crops.  Registration is pending EPA approval.  In trials conducted across the Northeastern United States in 2009 and 2010 both fall and spring applications of 73 g ai/ha demonstrated effective residual control of many common orchard weeds.  Tankmixtures with other herbicides that provide postemergence control were necessary for weeds present at the time of applications.  No crop injury was observed in any of these trials.

   Mesotrione-based herbicide products have been very popular with corn (field and sweet) growers. One issue that has limited mesotrione use in vegetable rotation systems has been an 18 month rotation restriction for many vegetables. Growers and extension personnel have inquired about reducing the amount of time needed to rotate to vegetable crops, specifically snap beans (Phaseolus vulgaris). Without a reduced rotation restriction, growers cannot legally use mesotrione products and then plant snap beans the following year. Syngenta is interested in reducing the rotational restrictions of Callisto, Lumax, Lexar, and Camix provided local data demonstrates there is good snap bean safety.  Field studies were conducted in 2010 in Pennsylvania (Rock Springs, Centre Co.) and Delaware (Georgetown, Sussex Co.) to simulate the carryover effect of mesotrione-products on several varieties of snap bean. Lumax, Lexar, and Camix were sprayed at 0.02, 0.15, 0.3, and 0.6X the normal use rate (2.47 lb ai/A) to simulate a range of potential carryover levels one year after application.  Herbicides were applied PRE at time of snap bean planting in early June.  After conducting greenhouse assays, three or four snap bean varieties were selected for the field studies, two exhibiting low tolerance (‘Envy’ and ‘Dart’) to mesotrione and the others exhibiting medium to high tolerance (‘Caprice’ and ‘Slenderpak’) were planted. Studies were arranged in a randomized complete block design with three replications. All plots were treated with POST herbicides to eliminate weed competition. Visual snap bean phytotoxicity evaluations were taken periodically throughout the growing period. Plots were hand harvested and final yields calculated. In Pennsylvania, across all varieties no more than 3% injury was observed at the 0.02X herbicide rate prior to harvest. At the 0.15X rate, Envy had 50-57% injury while Caprice and Slenderpak injury ranged from 17-28%. All varieties at the 0.3 to 0.6X rates had 35-93% injury. Yields for Envy were significantly different for all treatments at the three higher rates (0.15, 0.3, and 0.6X). In most cases, for Caprice and Slenderpak, yields were only significantly different from the check at the 0.6X rate. However, there were trends towards decreased yields with increased herbicide rate. In Delaware, the snap beans were terminated and replanted after one month since the majority of treatments caused severe injury. Even after replanting, significant injury was observed in the three highest rates in Caprice and Slenderpak at maturity. Only the highest rate caused greater that 20% injury to Envy and Dart. Yields were not collected due to Rhizoctonia that was observed in the snap beans at lower rates, confounding yield data. In addition to these studies, a complementary, two-year, field study is being conducted that evaluates actual carryover affects of Lumax and Lexar on several snap bean varieties at three different locations in Pennsylvania and Delaware. In summary, across both trials, from this preliminary trial data it appears that crop injury can be attributed to mesotrione and not the atrazine component of these products. Also, a number of factors can influence snap bean injury from mesotrione carryover including, variety, herbicide rate, soil type, and climatic conditions.

   Dry bean desiccation is common practice in New York State.  Preharvest herbicides are used to dry down green crop tissue, to desiccate uncontrolled weeds, and to even-out bean maturation.  The objective of this research was to compare the speed and overall effectiveness of a number of potential dry bean desiccants.  Herbicides that were evaluated included those currently registered in New York: flumioxazin (0.064 and 0.096 lb ai/A), carfentrazone (0.03 lb ai/A), glyphosate (1.0 lb ai/A), paraquat (0.5 lb ai/A) and sodium chlorate (6 lb ai/A).  Additionally, several unregistered products were tested: saflufenacil (0.044 and 0.088 lb ai/A), glufosinate (0.25 and 0.4 lb ai/A) and diquat (0.5 lb ai/A).  Several herbicide combinations were also tested. Trials were conducted in 2009 and 2010 at the Homer Thompson Vegetable Research Farm in Freeville NY.  Drybean ‘Red Kanner’ was grown in 2009, while ‘Cal Early’ was grown in 2010.  Trials were established as randomized complete block designs with three replications per treatment.  Applications were made when 30 to 40% of dry bean leaves (and 15 to 20% of the stems) had naturally desiccated.  Visual ratings of leaf and stem desiccation were taken 3, 7, and 14 days after treatment (DAT).  In both 2009 and 2010, flumioxazin and saflufenacil provided the highest levels of leaf and stem desiccation 3 DAT.  Desiccation levels continued to increase; by 7 DAT there was 95% or greater leaf desiccation in all flumioxazin and saflufenacil treatments.  Applications of paraquat or diquat provided 53 to 73% desiccation 3 DAT.  Further increases in defoliation were minimal (68 to 78% at 14 DAT) and were due to natural plant senescence.  Compared to paraquat, sodium chlorate caused a moderately higher degree of leaf desiccation (73% at 3 DAT and 90% at 14 DAT).  A tank mixture of a half rate of sodium chlorate (3 lb ai/A) and paraquat (0.25 lb ai/A) provided greater desiccation than the full rate of paraquat but less desiccation than the full rate of sodium chlorate.  Glyphosate applications produced a gradual desiccation response, but by 14 DAT there was 85 to 100% leaf desiccation.  However, the addition of 1 lb ai/A glyphosate to 0.064 lb ai/A flumioxazin delayed desiccation compared to the application of 0.064 lb ai/A flumioxazin alone.  Glufosinate applications provided slightly quicker desiccation than glyphosate, though by 14 DAT desiccation levels with the two herbicides were equivalent.  Of the currently registered products, flumioxazin at 0.064 and 0.096 lb ai/A will provide rapid desiccation of dry bean stems and leaves.  The addition of glyphosate will not enhance defoliation.  Saflufenacil should provide a capable alternative to flumioxazin.  Registration of saflufenacil as a dry bean desiccant is expected for the upcoming season.

   The IR-4 Project is a publicly funded effort to support the registration of pest control products on specialty crops. The IR-4 Project continues to meet specialty-crop grower's needs for weed control options despite the challenges of a mature market for herbicides and the selectivity of specialty crops to many of the more-recently-introduced herbicides. The Pesticide Registration Improvement Act continues to affect IR-4 submissions and EPA reviews of packages. IR-4 submitted herbicide petitions to the EPA from October 2008 to October 2009 for: Dicamba +2,4-D on teff; Paraquat on Perennial Tropical and Sub-tropical Fruit Trees; Quizalofop-p-ethyl on sorghum (grain) and Rapeseed subgroup 20A. From October 2008 through October 2009, EPA has published Notices of Filing in the Federal Register for: Glufosinate-ammonium on sweet corn; Linuron on dry pea and parsley; and Trisulfuron-methyl on garden beet. EPA established tolerances from October 2008 to October 2009 for: Endothall on vegetable, root and tuber group; vegetable, leaves of root and tuber group; vegetable, bulb group; vegetable, leafy except Brassica group; Vegetable Brassica, leafy group; vegetable, legume group; vegetable fruiting group; vegetable cucurbit group; fruits, citrus group; fruit, pome group; fruit, stone group; berry and small fruit group; grape; nut tree group; grain, cereal group; grain, cereal, forage, fodder, and straw group; grass, forage, fodder, and hay group; animal feed, non-grass group; mint and rice; Clopyralid on Swiss chard, Bushberry subgroup 13-07B, and annual strawberry (FL); Clethodim on Caneberry subgroup 13-07A, Bushberry subgroup 13-07B, peach, and globe artichoke; Flumioxazin on Leaf Petioles subgroup 4B, Vegetable Cucurbit group 9, and hops; Halosulfuron-methyl on vegetable, tuberous and corm, subgroup 1c; Pea and bean, succulent shelled, subgroup 6B, Pea and bean, dried shelled, except soybean, subgroup 6, Bushberry subgroup 13-07B, rhubarb, apple, and okra;

Prometryn on Leaf Petioles subgroup 4B, carrot, celeriac, cilantro, okra and parsley;

S-metolachlor on sesame, Melon subgroup 9A, Bushberry subgroup 13-07B, lowbush blueberry, Caneberry subgroup 13-07A, sweet sorghum, Leafy Brassica Greens subgroup 5B, turnip greens, carrot, cucumber, okra, Onion bulb subgroup 3-07A, and Onion Green subgroup 3-07B andThifensulfuron-methyl on safflower.

   Snap bean (‘Slenderpak’ and ‘Envy’), lima bean (‘Cypress’), and cucumber (‘Vlaspik’) were planted no-till on July 6. On August 11, glyphosate was applied to kill the planted crops and weeds, and in mid-August mustard and turnips were planted without tillage. Visual ratings were made on crop injury.

   Common lambsquarters and morningglory control 2 weeks after treatment was influenced by topramezone rate and the addition of atrazine. Large crabgrass and giant foxtail was affected by topramezone rate only. Pigweed species and common ragweed control was excellent regardless of the treatment.

   Snap bean was the only crop that showed any significant crop injury, and Envy was more sensitive to topramezone than Slenderpak. The addition of atrazine to topramezone had no effect on crop injury. 

   These results are preliminary and this trial will be repeated. Limited data shows good crop safety for lima bean, cucumber, mustard, and turnips. Replanting snap bean after sweet corn treated with topramezone needs to be examined further.

   Trials were conducted between 2008 and 2010 at the H.C. Thompson Vegetable Research farm in Freeville NY, and in growers’ fields.  The products and rates tested included: Cadet (fluthiacet-methyl, 0.004, 0.008 lb ai/A), Capreno (tembotrione + thiencarbazone-methyl, 0.04, 0.08 lb ai/A), Fierce (flumioxazin + pyroxasulfone, 0.14, 0.18 lb ai/A), Huskie (pryasulfotole + bromoxynil, 0.12, 0.24 lb ai/A) and Sharpen (saflufenacil, 0.056, 0.112 lb ai/A in 2008 and 2009; 0.022, 0.044, 0.066 in 2010).  When Cadet, Huskie, and Sharpen were used in 2008, sweet corn ‘Bonus’, ‘Overland’, and ‘Temptation’ showed virtually no injury.  Yields with each sweet corn variety were not reduced by 2X rates.  In 2009, all five herbicides were tested on the variety ‘Bonus’.  There was no injury or yield loss with 1X rates of all products, nor was there any injury with 2X rates of Cadet, Capreno or Sharpen.  The 2X rates of Huskie and Fierce caused 26 and 16% injury, respectively, although yields were not reduced.  In 2010, all five products were tested on eight sweet corn varieties: five fresh market [Sweet Ice, Honey N’ Pearl, Augusta, Brocade, Silver Queen] and three processing [GH4927, Bonus, Overland].  Corn maturation between varieties ranged from 74 to 92 days.  None of the eight varieties were notably injured by the 1X rates of Fierce or Huskie (some transitory injury of less than 20%).  While the 2X rates of these two herbicides caused unacceptable early injury (>20%), yields were unaffected.  Sharpen did not significantly injure or reduce yields at any tested rate.  The 1X rate of Cadet caused little injury, except in freshmarket varieties ‘Honey N’ Pearl’ (76 day) and ‘Augusta’ (79 day).  However, the 2X rate of Cadet injured all varieties except ‘Sweet Ice’ (74 day fresh market) and ‘Brocade’ (82 day fresh market).  Cadet failed to control annual grass weeds; therefore, yield reductions frequently occurred with both rates due to weed competition.  Capreno caused unacceptable (>20% injury) injury in all eight varieties: yields of 2X treatments were frequently reduced.  However, when Capreno was applied at the 1X rate, only yield of ‘GH4927’ was reduced.  Of the eight tested sweet corn varieties, ‘Bonus’, ‘Overland’, and ‘Silver Queen’ had no injury or yield reduction with 1X rates of any of the five herbicides.  Response of the other sweet corn varieties varied by product and by season.  Of the tested herbicides, Sharpen has the broadest potential for use.        

   Crabgrass (Digitaria spp.) is a problematic weed for many turf managers. The traditional approach of applying one application of a preemergence herbicide in the spring does not always provide adequate season-long control. Therefore, many turf managers will apply half the label rate in the spring prior to crabgrass germination and then make a sequential application of the same preemergence herbicide approximately 60 days later in order to extend the window of herbicide activity. Turf mangers, especially lawn care operators, often need increased flexibility in their preemergence herbicide applications due to the number of customers they have and the large application date window that they use. For most consistent crabgrass control, previous research and practical experience suggests the initial and sequential application should consist of the same active ingredient. However, that research was reported in 1991 and active ingredients and/or recommended rates of active ingredients have changed since then. Therefore, the objective of this research was to compare the effectiveness of various sequential applications of dithiopyr, prodiamine, and pendimethalin when the preemergence applications were followed by the same or a different herbicide for the sequential application. A four by four factorial was used with four herbicide treatments (dithiopyr at 0.28 kg/ha, prodiamine at 0.42 kg/ha, pendimethalin at 1.68 kg/ha, and untreated) used for the initial application at half label rates followed by the same four herbicide treatments used for the sequential application at half label rates. Additionally, full rates of dithiopyr at 0.56 kg/ha, pendimethalin at 3.36 kg/ha or prodiamine at 0.73 kg/ha were included for comparison in both 2009 and 2010 in West Lafayette, Indiana. Separate but adjacent experimental areas were used each year, and the experimental design was a randomized complete block with three replications. As expected, sequential applications of all nine herbicide combinations (omitting the untreated) resulted in less crabgrass cover by August (<21%) compared to single spring applications at the full rate (>25% cover) for dithiopyr, pendimethalin, and prodiamine. Because of the postemergence crabgrass control from dithiopyr, dithiopyr as the sequential June application following an untreated March application consistently provided better crabgrass control than when prodiamine or pendimethalin were used as a sequential application following no herbicide in March.  There were no significant differences in crabgrass cover when the same or different active ingredients were used for the initial and sequential applications. This suggests that turf managers can switch from one active ingredient to another when making sequential applications To support these findings, this study will be repeated in 2011 in West Lafayette, Indiana and at two locations near Lincoln, Nebraska.

   Field studies were conducted in 2009-2010 to evaluate a combination of dithiopyr and sulfentrazone. Applied as a liquid or granular formulations for preemergence (PRE) and postemergence crabgrass control. The ratio of dithiopyr and sulfentrazone was approximately 5:4, application rates were 0.5, 0.7, and 1.0 kg ai/ha. Application timings were PRE, 1-4 leaf, 1-2 tillers, and 3-5 tillers (2010 only).  All granular treatments were applied by hand to dry foliage with a shaker can to plots that were 0.9 by 3 m.  All liquid treatments were applied to 0.9 by 3 m plots with a single-nozzle CO₂ backpack sprayer system utilizing a 9504EVS nozzle tip which delivered 374 L/ha of spray solution at 221 kPa. Experimental design was a randomized complete block with 4 replications. Treatments were visually evaluated for crabgrass control in late August. In 2009 crabgrass control with PRE applications ranged from 90-99% while dithiopyr (2EW) alone at 0.6 kg/ha was 96%. Control of 1-4 leaf crabgrass ranged from 70-98% with the 1.0 kg/ha rate providing the highest level of control. Control of 1-2 tiller crabgrass ranged from 34-87%. Control significantly increased with increasing application rate. Crabgrass control was significantly greater with the granular formulation at 0.5 kg/ha. In 2010 granular and liquid formulations were evaluated in separate studies. 0.6 kg/ha of dithiopyr was included at each application timing. In the liquid formulation study crabgrass control with PRE treatments ranged from 76-86%. All treatments applied to 1-2 or 3-5 tiller crabgrass resulted in significantly less control relative to PRE treatments. In the granular formulation study PRE treatments provided 88-98% control. Control of 1-4 leaf crabgrass ranged from 85-98% and was equivalent to PRE treatments. Control of 1-2 tiller crabgrass ranged from 61-95% with application rates of 0.7 and 1.0 kg/ha providing equivalent control to  PRE treatments. Treatments applied to 3-5 tiller crabgrass provided 65-81% control and was significantly lower relative to PRE treatments. The results of these studies suggest that granular formulations of dithiopyr and sulfentrazone provide a significant level of postemergence crabgrass control up to 1-2 tillers.

   Fenoxaprop effectively controls crabgrass (Digitaria spp.) in tall fescue (Festuca arundinacea L.) turf but antagonism with growth regulating herbicides reduces potential to apply fenoxaprop in combination with many herbicides registered for broadleaf weed control.  Aminocyclopyrachlor is a new broadleaf weed control herbicide that has not been evaluated in combination with fenoxaprop.  Field experiments were conducted in Georgia, New Jersey, and Tennessee to investigate tank-mixtures of fenoxaprop with aminocyclopyrachlor for smooth crabgrass and white clover control.   Fenoxaprop alone exhibited substantial activity on smooth crabgrass but synergistic effects were detected with fenoxaprop + aminocyclopyrachlor treatments.  By 4 and 6 weeks after treatment (WAT), approximately 22 and 44% less fenoxaprop was required to achieve 80% smooth crabgrass control when the herbicide was tank-mixed with aminocyclopyrachlor at 220 and 330 g ai/ha, respectively.  Fenoxaprop did not reduce white clover control with aminocyclopyrachlor as 97% control was achieved by 4 WAT for all aminocyclopyrachlor + fenoxaprop treatments.  Tall fescue was not injured from any treatment.  Results suggest aminocyclopyrachlor enhances fenoxaprop efficacy for smooth crabgrass control in tall fescue.

   Homeowners, Master Gardeners, and Extension Agents have long complained that consumer herbicides were generally ineffective and information found in the Virginia Cooperative Extension Pest Management Guide (PMG) did little to aid consumers in product selection and use rates. In 2010, the Lawn Weeds section of Virginia Home Grounds and Animals PMG was corrected to address complaints from concerned individuals. The following problems were noted and corrected: 1) pest management recommendations were based on common chemical names of active ingredients yet most consumer products contain the full chemical name and not the common chemical name. To correct this problem the Virginia Department of Agriculture and Consumer Services (VDACS) database was searched to identify approximately 700 consumer herbicides that represented 34 unique active ingredients. Interestingly, over 560 of these consumer products contained various combinations of just 8 active ingredients. A table was created to shows all synonyms that were filed with VDACS for consumer herbicides registered in Virginia and the number of consumer products that uses each active ingredient. The table of synonyms allows consumers to cross reference the full chemical names with the common chemical name used in the PMG. 2) In the old PMG, herbicide rates were expressed in pounds active ingredient per acre and of little use to consumers.  Extension Agents, who understood these rates, could not find any consumer products that matched or allowed for equivalent use rates to those recommended in the PMG. To correct this problem, a professional equivalency formula was created and professional equivalency constants (PEC) were calculated for each unique combination of active ingredients registered in Virginia. The formula uses the percentage active ingredient, amount of product per container, and square footage treated per product container to determine how the consumer product compares to professional rates that are recommended by Virginia Tech. Most consumer products were found to be 0.46 to 0.79 times the recommended professional rate. Consumers are advised to choose the product that returns a value closest to 1 when using the formula. When evaluating consumer product labels, it was noted that many products have a suggested use rate followed by a maximum use rate. The maximum use rate is often expressed in pounds of active ingredient per acre and is not understandable by consumers. These maximum rates are typically twice the suggested rates and less than the professional rates on which the PEC is based. As an extension specialist, one struggles to give consumers and Extension Agents sound advice in using consumer products when suggested rates on these products are far less than Extension recommended rates, yet the product label legally allows for higher rates. The general belief among research scientists and company cooperators is that consumer rates must be reduced to allow for inevitable over application by consumers. It seems hypocritical to concede that over application of any herbicide is a breach of federal law with a concomitant assumption that homeowners will over apply consumer products.  The use of PECs to pick consumer products is a first step to improving consumer product effectiveness for Virginians. In subsequent PMG revisions, the concept of consumer product rates will be further evaluated.

   Grower and agrichemical retailer education and training has been identified as a critical path in advancing the adoption of proactive best management programs to delay or mitigate the development of herbicide resistant weeds. Universities, private sector companies, crop commodity groups, and other groups have all been active in developing and distributing training materials to growers and the agricultural community at large. In February 2010, a proposal was made and accepted by the WSSA Herbicide Resistant Plants Committee (E12) and the special task force on Herbicide Resistance Education (S71) to form a team of public and private sector weed scientists (see list of authors) to review current web-based herbicide resistance training modules, with the intent to update and modify these modules as appropriate. The broad goals of the effort are to: (1) provide the most up-to-date information on causes and best methods for managing resistance, (2) increase consistency of basic messages to growers and retailers, (3) demonstrate to the public a unified public and private sector message of a science-based approach to managing resistance, and (4) increase incorporation of herbicide resistance training into formal certification programs such as the Certified Crop Advisor program. The team is developing five modules around the following questions: (1) Why is proactive resistance management important? (2) How do herbicides work and what is herbicide site-of-action? (3) What is herbicide resistance? (4) How do I identify resistance to herbicides? and (5) How do I manage resistance? In addition, the team, in cooperation with other weed scientists and agronomists, is developing a separate module to address the specific issue of the impact of resistance management practices on conservation tillage. Each of these modules will be developed in multiple formats (web-based training, PowerPoint slides, and videos). The modules will be made available to all who wish to use them and will be maintained and freely distributed by the WSSA. WSSA will also work with grower organizations and others to develop and distribute these materials.

   In early 2008, pyroxsulam (PowerFlex) was registered by the US-EPA for use on wheat for postemergence control of key annual grasses including Italian ryegrass (Lolium multiflorum) and downy brome (Bromus tectorum) and annual broadleaves such as Amaranthus spp., Brassica spp., Geranium spp. Veronica spp. and wild pansy (Viola tricolor). PowerFlex is formulated as a 7.5% active ingredient water dispersible granule for use in winter wheat. In 2010, efficacy studies with PowerFlex were conducted against Italian ryegrass and other important weeds, such as common chickweed (Stellaria media), purple deadnettle (Lamium purpureum), horseweed (Conyza canadensis), and wild garlic (Allium vineale), in the DELMARVA winter wheat production area. All treatments were applied in the spring, at “first green-up,” and PowerFlex was applied at 3.5 oz/A (0.0164 lb ai/A).

   PowerFlex provided excellent control of Italian ryegrass (92%) compared to Osprey (mesosulfuron-methyl) at 4.75 oz/A (92%) and Everest (flucarbazone-sodium) at 0.6 oz/A (72%). In a separate trial against purple deadnettle, Osprey at 4.75 oz/A  and PowerFlex both provided fair to good control (72%) compared to Harmony Extra SG (thifensulfuron-methyl and tribenuron-methyl)  at 0.75 oz/A (80%). In the same trial PowerFlex provided fair to good control (70%) of common chickweed, similar to Harmony Extra (83%) and better than Osprey (33%). In another trial where horseweed was the predominant weed, PowerFlex provided 77% control when tank-mixed with 0.25% non-ionic surfactant and 2% UAN (30-0-0). In the same trial Harmony Extra SG at 0.75 and 0.9 oz/A, also tank-mixed with 0.25% non-ionic surfactant, provided 60 and 87% control of horseweed, respectively. In three trials against wild garlic, control with PowerFlex ranged from 90 to 95% compared to 88 to 95% control for Harmony Extra SG at 0.75 oz/A. These trials demonstrate that PowerFlex not only provides excellent control of Italian ryegrass but other important weeds such as wild garlic, common chickweed, horseweed and purple deadnettle.

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PowerFlex is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.

   The first US registration for atrazine herbicide was granted December 1958, for use in corn  and nonselective weed control in noncrop areas.   Since then, US farmers have relied on atrazine as an effective and reliable broadspectrum foundation herbicide in corn, grain sorghum and sugar cane production for control of many troublesome weeds like pigweed and lambsquarters, as well as providing partial control of important grasses including foxtail and barnyardgrass.  Atrazine is used preferentially in reduced till and no-till corn, which helps reduce soil erosion and runoff into streams and rivers.

   Field experiments were established in Charles Town, and Morgantown, WV, in 2010, to compare the effect of broadcast and banded application of preemergence herbicides on corn yield and weed biodiversity levels.  Individual experimental plots in Charles Town had an area of 0.5 ha, simulating grower-fields, and each plot in Morgantown had an area of 7.5x10^-3 ha.  A pre-mixture of atrazine, metolachlor, and mesotrione was applied broadcast to provide 0.84, 2.24, and 0.224 kg ai/ha, respectively, or banded 38 cm wide over corn rows spaced 75 cm apart at the rates of 0.42, 1.12 and 0.112 kg ai/ha, respectively, prior to weed emergence when the corn was 10 to 15 cm tall.  Giant foxtail (Setaria faberi Herrm.) and yellow nutsedge (Cyperus esculentus L.) were the predominant weeds in Charles Town, whereas yellow foxtail (Setaria glauca (L.) P. Beauv.) and yellow nutsedge were the predominant weeds in Morgantown.  Charles Town experienced drought-like conditions and moderate weed pressure (30 to 50% ground cover in untreated plots) during the 2010 growing season, whereas precipitation was close to average in Morgantown with high weed pressure (>90% ground cover in untreated plots).   While no yield differences were recorded between broadcast and banded plots, broadcast application resulted in 28 and 103% higher yields in Charles Town and Morgantown, respectively, whereas banded application resulted in 26 and 65% higher yields, in Charles Town and Morgantown, respectively, compared to untreated plots.  Simpson’s Diversity Index analysis generated 1-D values of 0.63 and 0.67 in banded and untreated plots, respectively, reflecting probability levels of two randomly-selected weeds to belong to different species one month after treatment in Morgantown.  At this time and location, broadcast application resulted in total weed control, thus lacking a 1-D value.  In Charles Town, 1-D values were 0.80, 0.76, and 0.76 for banded, broadcast, and untreated plots, respectively.  Shannon’s Index for Biodiversity analysis generated H values of 1.15 and 1.37 in banded and untreated plots, respectively, in Morgantown, and 1.88, 1.48, and 1.68 for banded, broadcast, and untreated plots, respectively, in Charles Town; according to Shannon’s Index an H value > 1.5 is considered to be biologically-diverse. 

   Edamame is a food grade soybean (Glycine max (L.) Merr.) that is very popular in East Asia. More recently, it is becoming more popular in the United States. Because it is a healthy source of protein and energy, edamame is used as a snack food, in salads and stir fry and many other dishes. Food grade soybeans differ from feed grade soybeans (fed to livestock) in that they are normally larger in size and sweeter in taste. Edamame is harvested as an immature soybean at reproductive stage 6 (R6), when the soybean pods are green and have two to three fully developed green-colored beans inside the pod. Currently, the vast majority of edamame is produced in Asia and imported to the United States. Because of its large market potential, Penn State is working with other universities, USDA, and private industries to introduce U.S.-developed edamame varieties that would be locally grown, to American markets. One necessary aspect for large scale production of edamame is adequate and economical weed control options. Replicated, small-plot field studies were conducted in 2008 to evaluate herbicide tolerance of five edamame varieties (‘Butter’, ‘Envy’, ‘Mooncake’, ‘VS3622’, and ‘VS3688’) and a standard, feed grade, agronomic soybean variety, ‘Pioneer 93M11’. Bentazon, chlorimuron, cloransulam, fomesafen, imazamox, s-metolachlor, and pendimethalin were applied preemergence (PRE) and/or postemergence (POST) at standard soybean use rates. Across all varieties, none of the PRE herbicides caused any crop injury. In general, depending on the treatment, initial injury from POST applications ranged from 7 to 30%, including the control ‘Pioneer 93M11’ variety. However, late season crop injury ratings revealed that the POST herbicides caused no more than 11% injury to any of the varieties which is similar to what was observed with the control variety. From these and other efforts, Syngenta has secured a Section 3 label for Dual Magnum that includes use in edamame (immature soybean seed) production. Other companies are working to obtain herbicide product labels that list edamame. Products that are potentially pending approval include Basagran, Command, Prowl H2O, Pursuit, Raptor, Reflex, Treflan HFP, and Select.

   As more weeds become resistant to glyphosate, many wonder if the LibertyLink® soybean (Glycine max) system will be the answer to this problem. Glufosinate (Ignite 280®, formerly known as Liberty) has the potential for both burndown in no-till and for control of emerged weeds postemergence (POST). However, there are several benefits and challenges to consider and these are forefront on many university extension weed scientist’s minds. In central Pennsylvania, initial investigations of LibertyLink soybean programs to evaluate weed control were conducted from 1995 – 1999 and then were revived in 2008 prior to commercial marketing of LibertyLink soybean varieties. These field experiments compared POST-applied glufosinate alone and in sequence with preemergence (PRE)/residual herbicides (e.g., pendimethalin or s-metolachlor + fomesafen premix). In general, glufosinate (0.36 or 0.4 lb ai/acre) treatments were applied with ammonium sulfate as an adjuvant. Studies were arranged in a randomized complete block design with three replications. Visual weed control evaluations were taken periodically throughout the growing period.  Late season evaluations of eight studies revealed that glufosinate herbicide alone provided 80 – 83% control of giant foxtail (Setaria faberi), common lambsquarters (Chenopodium album), velvetleaf (Abutilon theophrasti), and smooth pigweed (Amaranthus hybridus) when applied early postemergence (EPOST).  However, when glufosinate was applied in combination with a PRE-residual herbicide or in a glufosinate (EPOST) followed by glufosinate (POST) program, control of these same weed species improved to 90 – 97%. These study results combined with research at other universities and with information from the glufosinate product label provide some practical guidance for soybean growers. Benefits of the LibertyLink system include: good, in-crop, annual weed control option; use of a different mode of action (non-glyphosate) as a possible herbicide resistance management tactic; wide POST application window; currently, no resistant weed species; and good crop rotation flexibility.  Some challenges include: weaker than glyphosate on certain annual weeds (especially grasses) and perennials and in burndown situations; thorough spray coverage necessary for effective weed control; time of day and climatic conditions can affect glufosinate performance; and possible higher cost of glufosinate- vs. glyphosate-containing herbicide products. In a well planned crop rotation, LibertyLink soybean system has the potential to provide effective weed control and reduce the reliance on glyphosate when used in an integrated weed management scheme. For example, in no-till LibertyLink soybeans, use a glyphosate-based burndown mixture that includes a reduced rate residual herbicide followed by an in-crop application of glufosinate.

   Glufosinate has provided excellent weed control postemerge (POST) in glufosinate-resistant soybeans. However, as a means of herbicide resistance strategies laid out by Bayer and other companies, the inclusion of a residual soil-applied herbicide is recommended. In today’s rush to plant soybeans earlier and large planting equipment, results in crop emergence before growers and retailers can apply their soybean residual soil-applied herbicides. Most soil-applied herbicides must be applied before soybean emergence or significant crop response may occur.

   Field studies were conducted through the U.S. to evaluate residual herbicides with the first application of glufosinate and demonstrate how that compares to either a PRE fb POST or POST applications alone.

   Warrant^TM herbicide is a new encapsulated acetochlor (33% or 3 lb/gal) specifically designed for postemergence applications in Roundup Ready® crops.   Warrant provides residual control of small seeded broadleaves and annual grasses.  Warrant can be tank-mixed with Roundup® Brand Agricultural herbicides.  Applications to soybeans should be made after soybeans are completely emerged but before soybeans reach growth stage R2, and labeled rates include 1.25 to 2 qt/A depending on soil type.  The optimum timing and rate in most situations is when soybeans are V2-V3 at 1.5 qt/A.  Warrant may be used in field corn from emergence to 30 inch corn, drop nozzles are recommended after 24 inch corn simply to improve weed and soil coverage under the crop canopy.  Corn label rates include 1.5 to 3 qt/A depending upon soil type.  Data demonstrates at 1.5 qt/A, Warrant will provide up to 40 days of residual control of grasses and small seeded broadleaf weeds, including tall waterhemp, common lambsquarters, and pigweed species.  Warrant is not designed to control emerged weeds, therefore should be applied with Roundup to control emerged weeds.