If registered for use on vegetable soybean, pyroxasulfone would expand the options for weed management systems in the crop. In order to determine the potential crop injury risk of pyroxasulfone on vegetable soybean, the objective of this work was to quantify vegetable soybean tolerance to pyroxasulfone applied PRE and EPOST. Twenty-one vegetable soybean and two grain-type soybean cultivars were treated with pyroxasulfone at 417 g ai ha^-1 (twice the recommended field use rate) PRE, EPOST, or not treated. Plant population density was unaffected by pyroxasulfone. Only low levels (<10%) of crop injury were observed within a few weeks after PRE and EPOST treatments. Soybean cultivars were not differentially affected by pyroxasulfone, as evidenced by the lack of interactions between cultivar and treatment for any crop response variable. The low amount of risk of crop injury associated with pyroxasulfone is no different for vegetable soybean cultivars grown in the US for commercial production than grain-type soybean.

Nomenclature: Bentazon; fomesafen; imazamox; linuron; pyroxasulfone; sulfentrazone; soybean, Glycine max (L.) Merr.

Field studies were conducted to determine the effect of metam sodium and S-metolachlor applied through drip irrigation on yellow nutsedge, common purslane, bell pepper, and tomato (injury and yield) in plasticulture. Treatments consisted of weed-free, weedy, S-metolachlor alone at 0.85 kg ha-¹, methyl bromide, metam sodium (43, 86, 176, and 358 kg ai ha^-1) alone, and metam sodium (43, 86, 176, and 358 kg ai ha^-1) followed by S-metolachlor at 0.85 kg ha^-1. Metam sodium and S-metolachlor was applied preplant 2 wk before and 2 wk after transplanting (WAT) through drip irrigation, respectively. No injury was observed to bell pepper and tomato from metam sodium alone, or metam sodium fb S-metolachlor treatments. With the exception of yellow nutsedge density 15 WAT in bell pepper, herbicide program did not influence yellow nutsedge and common purslane density at 4 and 6 WAT and bell pepper and tomato yield. At 15 WAT, yellow nutsedge density was lower in treatments that received metam sodium fb S-metolachlor compared to those treatments that only received metam sodium. Drip-applied metam sodium at 176 and 358 kg ha^-1 in both bell pepper and tomato provided similar control of common purslane, and yellow nutsedge, produced comparable yields, and failed to elicit any negative crop growth responses when compared to MeBr. In conclusion, metam sodium at 176 and 358 kg ha^-1 fb S-metolachlor 0.85 kg ha^-1 is an effective MeBr alternative for season long weed control in plasticulture bell pepper and tomato.

Nomenclature: Metam-sodium; S-metolachlor; common purslane, Portulaca oleracea L.; yellow nutsedge, Cyperus esculentus L.; bell pepper, Capsicum annuum L.; tomato, Solanum lycopersicum L.

Field experiments were conducted at the Ohio Agricultural Research and Development Center in Wooster, OH in 2002 and 2004 to evaluate the tolerance of tomato varieties to halosulfuronmethyl, a selective herbicide used for POST control of broadleaf weeds and nutsedge (Cyperus). POST herbicide treatments included halosulfuron-methyl at 0, 34.7 and 70 g ai ha^-1. Plots were evaluated at 1, 3, and 6 wk after treatment (WAT), and yield was recorded at the end of the season. Minimal crop injury was observed 1 and 3 WAT in plots treated with both halosulfuronmethyl rates only in 2002. Although the crop recovered from herbicide injury when treated with the lower rate at 6 WAT, ‘Ohio 8245’, ‘M82’, and ‘E6203’ showed injury at this interval when treated with halosulfuron-methyl at 70 g ha^-1. No injury was observed with either rates in 2004. No significant yield reduction was observed in any of the varieties in the test plots. These results indicate that differential tolerance to halosulfuron-methyl does not exists among these tomato varieties with the exception of E6203 and M82.

Nomenclature: Halosulfuron; tomato, Solanum lycopersicum L.

Field studies were conducted in 2014 and 2015 at Pontotoc, MS to evaluate combinations of metam-potassium and S-metolachlor for yellow nutsedge control and sweetpotato crop response. Treatments consisted of a factorial of five metam-potassium rates (0, 149, 261, 372, and 484 kg ha^-1) by three S-metolachlor rates (0, 0.80, and 1.34 kg ha^-1). Additionally, a hand-weeded check was included for comparison. Crop injury was limited to ≤4% at 4 weeks after transplanting (WAP) and was transient. At 2 WAP yellow nutsedge control was 58, 74, and 76% in plots treated with S-metolachlor at 0, 0.80, and 1.34 kg ha^-1, respectively. Nutsedge control in all treatments decreased from 2 to 15 WAP. At 15 WAP, S-metolachlor at 0, 0.80, and 1.34 kg ha^-1 provided 35, 68, and 70% yellow nutsedge control, respectively. Metam-potassium rate did not influence yellow nutsedge control after transplanting. Sweetpotato yields in the hand-weeded check were 4,640; 22,180; 7,180; 34,000; and 1,360 kg ha^-1 for jumbo, no. 1, canner, marketable, and cull grades, respectively. S-metolachlor applied at either 0.80 or 1.34 kg ha ^-1 provided jumbo, no. 1, and marketable sweetpotato yields equivalent to the hand-weeded check. Canner and cull yields were not influenced by S-metolachlor rate. Metam-potassium rates used in the present study resulted in yields equal to or greater than the hand-weeded check.

Nomenclature: Metam-potassium; S-metolachlor; yellow nutsedge, Cyperus esculentus L.; sweetpotato, Ipomoea batatas L. Lam.

Field experiments were conducted at the North Central Agricultural Research Station in Fremont, OH in 2009 and 2010 to evaluate the tolerance of tomato to fomesafen and the efficacy of this herbicide on weed control. The crop was machine-transplanted in June 5, 2009 and June 3, 2010. Herbicide treatments were applied using a CO₂ pressurized (276 kPa) backpack sprayer with 8002VS nozzle tips delivering 234 L ha^-1. Pre-transplant (PRETP) treatments were applied on June 4, 2009, and May 27, 2010. Treatments included fomesafen at 280, 350, 420, 560, and 840 g ai ha^-1. Minimal crop injury was observed 7 and 14 d after treatment (DAT) in plots treated with fomesafen at 840 g ha^-1 both years. None of the treatments caused crop injury either year at 42 DAT. Fomesafen at the highest rate provided acceptable annual grass, common purslane, and redroot pigweed control 42 DAT. Tomato yield was not reduced by the application of fomesafen. Registration of fomesafen herbicide would provide tomato growers an opportunity to control weeds caused by late emergence or poor initial control following a burndown herbicide application in tomato.

Nomenclature: Fomesafen, tomato, Solanum lycopersicum L.

Tomato grafting is practiced worldwide as an innovative approach to manage stress from drought, waterlogging, insects, and diseases. Metribuzin is a commonly used herbicide in tomato but has potential to cause injury after application if plants are under stress. The influence of metribuzin on grafted tomato under drought-stress has not been studied. Greenhouse experiments were conducted in Raleigh, NC to determine the tolerance of drought-stressed grafted and non-grafted tomato to metribuzin. The tomato cultivar ‘Amelia’ was used as the scion in grafted tomato, and for the non-grafted control. Two hybrid tomato ‘Beaufort’ and ‘Maxifort’ were used as rootstocks for grafted plants. Drought-stress treatments included: no drought-stress; 3 d of drought-stress before metribuzin application with no drought-stress after application (3 d DSB); and 3 d of drought-stress before metribuzin application with 3 d of drought-stress after application (3 d DSBA). Metribuzin was applied at 550 g ai ha^-1. No difference in injury from metribuzin was observed in grafted and non-grafted plants. However, at 7 and 14 d after metribuzin treatment (DMT), less injury was observed on tomato in the 3 d DSBA treatment (5 and 2% injury, respectively) than on plants in the 3 d DSB treatment (15 and 8% injury, respectively) or those that were never drought-stressed (18 and 11% injury, respectively). Photosynthesis and stomatal conductance measured prior to metribuzin application were reduced similarly in grafted and non-grafted tomato subjected to drought-stress. Photosynthesis and stomatal conductance of grafted and non-grafted tomato at 7 DMT was not different among drought-stress treatments or metribuzin treatments. Grafted and non-grafted tomato plants under drought-stress exhibit similar tolerance to metribuzin. The risk of metribuzin injury to grafted tomato under drought-stress is similar to non-grafted tomato.

Nomenclature: Metribuzin; tomato, Solanum lycopersicum L.

Field studies were initiated in the 2013-14 and 2014-15 growing seasons to evaluate the potential of soil solarization (SS) treatments for their efficacy on weed control and crop yields and to compare SS to 1,3-dichloropropene (1,3-D) chloropicrin (Pic) fumigation. Each replicate was a bed with dimension 10.6 m long by 0.8 m wide on top. The center 4.6 m length of each bed, referred to as plots, was used for strawberry plug transplanting and data collection. Treatments included: i) 1,3-D Pic (39% 1,3-dichloropropene 59.6% chloropicrin) that was shank-fumigated in beds at 157 kg ha^-1 and covered with VIF on August 30 in both seasons; ii) SS for a 6 wk duration initiated on August 15, 2013 and August 21, 2014 by covering the bed with 1 mil clear polyethylene tarp; iii) SS for a 4 wk duration initiated on September 6, 2013 and September 3, 2014; iv) SS 4 wk treatment initiated September 6, 2013 and September 3, 2014 and replaced with black VIF on October 4, 2013 and October 1, 2014 and v) a nontreated control covered with black VIF on October 4, 2013 and October 1, 2014. In both seasons, following completion of the preplant treatments, ‘Chandler’ strawberry was planted in two rows at a 36 cm in-row spacing in plots during the first wk of October. Over both seasons, the 6 wk SS treatment consistently lowered the weed density compared to the nontreated control. Weed density in the 6 wk SS treatment was not statistically different from the 4 wk SS treatments in the 2013-14 growing season. In both seasons, crop yield in the 4 wk SS was significantly lower than other treatments.

Nomenclature: Chloropicrin, 1,3-dichloropropene, strawberry, Fragaria xananassa.

Field studies were conducted in various peanut production regions of Texas and Oklahoma during the 2013 and 2014 growing seasons to determine peanut response to single and sequential postemergence applications of pyraflufen-ethyl at the labelled use rate (3.6 g ai ha^-1). Pyraflufen-ethyl injured peanut in all single and two-application treatments. Injury consisted of white spots on leaves up to 14 d after treatment and became small necrotic spots on older leaf tissue. No injury was apparent on any new growth. Injury did not translate into yield loss in three of five locations; however, yield reductions (approximately 26%) were observed in two of five locations. Peanut grade was not affected by pyraflufen-ethyl applications.

Nomenclature: Pyraflufen, peanut, Arachis hypogaea L.

Methiozolin is an isoxazoline herbicide being investigated for selective POST annual bluegrass control in managed turfgrass. Research was conducted to evaluate methiozolin efficacy for controlling two annual bluegrass phenotypes with target-site resistance to photosystem II (PSII) or enolpyruvylshikimate-3-phosphate synthase (EPSPS)-inhibiting herbicides (i.e., glyphosate), as well as phenotypes with multiple resistance to microtubule and EPSPS or PSII and acetolactate synthase (ALS)-inhibiting herbicides. All resistant phenotypes were established in glasshouse culture along with a known herbicide-susceptible control and treated with methiozolin at 0, 125, 250, 500, 1000, 2000, 4000, or 8000 g ai ha^-1. Methiozolin effectively controlled annual bluegrass with target-site resistance to inhibitors of EPSPS, PSII, as well as multiple resistance to EPSPS and microtubule inhibitors. Methiozolin rates required to reduce aboveground biomass of these resistant phenotypes 50% (GR₅₀ values) were not significantly different from the susceptible control, ranging from 159 to 421 g ha^-1. A phenotype with target-site resistance to PSII and ALS inhibitors was less sensitive to methiozolin (GR₅₀ = 862 g ha^-1) than a susceptible phenotype (GR₅₀ = 423 g ha^-1). Our findings indicate that methiozolin is an effective option for controlling select annual bluegrass phenotypes with target-site resistance to several herbicides.

Nomenclature: Methiozolin, annual bluegrass, Poa annua L.

Brassicaceae weeds can be problematic in canola varieties that have not been modified to resist specific broad-spectrum herbicides. The overall objective of this study was to evaluate the potential for increased rapeseed seeding rate as a management strategy for flixweed. To accomplish this objective, a field study was conducted to determine crop seeding rate effects on canopy light transmission and rapeseed yield characteristics, as well as a greenhouse study to determine morphological and photosynthetic responses of flixweed to decreasing irradiance levels. Results from the field study indicated that light transmittance through the canopy decreased linearly as crop seeding rate increased from 1.8 to 9.0 kg ha^-1. Increasing crop seeding rate did not influence rapeseed aboveground biomass, seed yield, and harvest index, but negatively affected rapeseed seed oil content in one of two siteyears. Greenhouse study results indicated that declining irradiance levels caused reductions in flixweed biomass, root allocation, and photosynthetic light compensation point. Flixweed leaf allocation, foliage area ratio, and specific foliage area increased in response to decreasing irradiance levels. Combined results of field and greenhouse studies suggest that increasing rapeseed seeding rate can suppress flixweed growth while not causing yield penalties from increased intraspecific competition. However, increased rapeseed seeding rate might not be an adequate control strategy on its own because flixweed displays characteristics of a shade-tolerant species.

Nomenclature: Flixweed, Descurainia sophia (L.) Webb. ex. Prantl; rapeseed, Brassica napus L.