Complaints regarding the sensitivity of rice to florpyrauxifen-benzyl and off-target movement of the herbicide occurred following its commercial launch in 2018 in the midsouthern United States. These two concerns encouraged the exploration of an alternative application method for florpyrauxifen-benzyl in rice. A field study was conducted in 2020 and 2021 to determine if coating florpyrauxifen-benzyl on urea would reduce negative impacts of the herbicide to rice. Five commercial rice lines were evaluated: ‘Diamond’, ‘Titan’, ‘RT7321 FP’, ‘RT7521 FP’, and ‘XP753’. Florpyrauxifen-benzyl coated on urea at a 2× rate (60 g ai ha–1) reduced rice injury in one of five commercial rice lines in 2020 and four of five commercial rice lines in 2021, compared to spray applications at the same rate. In 2020, ‘RT7521 FP’ exhibited a 17-percentage point injury reduction when coating florpyrauxifen-benzyl on urea at a 2× rate vs. the same rate sprayed. In 2021, rice injury was reduced by 26, 10, and 27 percentage points in the commercial rice lines ‘Diamond’, ‘Titan’, and ‘XP753’, respectively, following coated urea vs. spray applications at 4 wk after treatment (WAT). ‘XP753’ exhibited reduced injury (15 percentage points) by coating florpyrauxifen-benzyl at a 1× rate (30 g ai ha–1) 4 WAT in 2021, and another, ‘Diamond’, had comparable groundcover to nontreated plots when florpyrauxifen-benzyl was coated on urea at a 1× rate rather than the reductions observed from the spray application at a 2× rate. Yield differences were a function of urea rate rather than application method, where in six out of ten instances greater rough rice grain yield occurred at the higher rate. Findings from this experiment indicate that coating florpyrauxifen-benzyl on urea can reduce the amount of injury observed, especially in areas of overlap where you would have a 2× rate.

Florpyrauxifen-benzyl has generated complaints and concerns around rice injury and off-target movement to soybean since its commercial launch in 2018. Developing a precise method for applying florpyrauxifen-benzyl was imperative for its continued use. Experiments were conducted in 2020 and 2021 to evaluate rice weed control as influenced by preflood application interval and flood loss following florpyrauxifen-benzyl at 30 g ai ha−1 applied as a spray or coated on urea. In a preflood application experiment, coating florpyrauxifen-benzyl on urea and applying it the day of flood establishment and 5 and 10 d prior to flooding (DPTF) resulted in lower yellow nutsedge, broadleaf signalgrass, and barnyardgrass control than when the herbicide was spray at 3 and 5 wk after final treatment (WAFT). Coating florpyrauxifen-benzyl onto urea provided only 61% to 63% yellow nutsedge control at 3 and 5 WAFT, which was 35 to 37 percentage points lower than when the spray was applied at 5 or 10 DPTF. Likewise, rice yields following applications of florpyrauxifen-benzyl coated onto urea were 1,200 kg ha−1 less than yields following spray applications. Florpyrauxifen-benzyl coated onto urea and clomazone provided lower levels of weed control than spraying the herbicide alone, suggesting an explanation for the yield losses. The timing of flood loss experiment suggested that when florpyrauxifen-benzyl coated onto urea at 30 g ai ha−1 was applied preflood and flood was relinquished at 2 h, 24 h, and 7 d after flood establishment, hemp sesbania and yellow nutsedge control were not affected. However, loss of floodwater 2 h after flood establishment resulted in lower barnyardgrass control than when the flood was lost 24 h and 7 d after flooding. Generally, the period between a herbicide application and flooding completion should be minimized to aid in weed control. These results indicate the importance of maintaining a flood for weed control and nutrient management.

Broadleaves, grasses, and nutsedge species are persistent problems with limited management options for strawberry growers in Florida. Field experiments were conducted in 2015-2016 (year 1) and 2016-2017 (year 2) at the Gulf Coast Research and Education Center in Balm, FL, to evaluate weed control and strawberry tolerance to herbicides applied through the drip irrigation. 2940 g ai ha-1 EPTC, 105 g ai ha-1 flumioxazin, 570 g ai ha-1 fomesafen, 52 g ai ha-1 halosulfuron, 3585 g ai ha-1 napropamide, oxyfluorfen 560 g ai ha-1, and 1070 g ai ha-1S-metolachlor were applied through a single drip tape at 7 or 14 d prior to transplanting. Halosulfuron was the most injurious herbicide, causing 18 and 46% injury at 35 d after transplanting (DATP) in year 1 when the herbicide was applied 7 and 14 d prior to transplanting, respectively. However, strawberry plants recovered from the initial injury and there was no reduction in total berry yield. None of the other herbicides evaluated elicited significant crop injury nor reduced berry yield. Averaged over application timings, EPTC, fomesafen, and napropamide suppressed yellow nutsedge emergence to 49, 64, and 41% of the nontreated control, respectively. Flumioxazin, fomesafen, and halosulfuron suppressed black medic emergence to 55, 52, and 55% of the nontreated control, respectively. None of the herbicides evaluated adequately suppressed Carolina geranium. Overall, results suggest that the evaluated herbicides with the exception of halosulfuron are safe for use on strawberry and would give growers an alternative management option. Drip-applied herbicides permit application closer to the transplant date and would be helpful as part of a weed control program for weed suppression.

A series of greenhouse studies examined the effectiveness of PRE- and POST-applied sulfentrazone in controlling purple and yellow nutsedge as influenced by selective tissue exposure. In addition, 14C-sulfentrazone was utilized to contrast absorption and translocation resulting from these exposures. Consistent control with preemergence applications to germinating tubers was obtained with a combined root and shoot zone exposure. Yellow nutsedge was more susceptible than purple nutsedge. Performance of the separate root and shoot zone exposure was soil pH- and nutsedge-species dependent. POST-foliar applications to established nutsedge were more effective when sulfentrazone was allowed to contact the soil surface. 14C-sulfentrazone was readily absorbed by the roots and translocated to the foliage of both species in hydroponic culture.

Greenhouse studies were conducted to determine purple and yellow nutsedge response to selective placement of a 5-cm layer of pyrithiobac sodium-treated soil above, below, or above and below nutsedge tubers. Pyrithiobac sodium at 36 or 72 g ae ha−1 applied postemergence as foliar, soil, or foliar and soil treatments also was evaluated. Pyrithiobac sodium applied above, below, or above and below nutsedge tubers reduced yellow and purple nutsedge shoot number, shoot regrowth, and root-tuber dry weight at least 90%. Foliar-only treatment of pyrithiobac sodium was less effective at reducing emerged purple and yellow nutsedge numbers than application to soil only or to foliage and soil. Best reduction in yellow and purple nutsedge growth with pyrithiobac sodium was obtained with soil-incorporated treatments.

Field experiments conducted in 1991, 1992, and 1993 evaluated Palmer amaranth and devil's-claw control and cotton injury with pyrithiobac applied PPI, PRE, or POST. Pyrithiobac at 36 or 71 g ae/ha applied PPI, PRE, or POST did not injure cotton. Pyrithiobac at 140 g/ha applied PPI or PRE injured cotton 9 to 11% 6 wk after treatment. Cotton recovered and no injury was observed 12 wk after treatment. Pyrithiobac applied PPI and PRE at 71 g/ha controlled Palmer amaranth at least 97% 6 wk after treatment. Palmer amaranth control with pyrithiobac applied POST was more variable and influenced by environmental conditions. Palmer amaranth control with 71 g/ha of pyrithiobac exceeded that with 36 g/ha. Devil's-claw control with pyrithiobac was better with POST applications than PPI or PRE applications. Pyrithiobac applied POST at 140 g/ha controlled devil's-claw 83–97%. These studies indicate that pyrithiobac can effectively control Palmer amaranth and devil's-claw in cotton on the Texas Southern High Plains when applied at appropriate rates and timings.

Greenhouse studies were conducted to determine the response of purple and yellow nutsedges to selective soil placement of 5 cm of soil treated with imazethapyr above and/or below the nutsedge tubers. Early postemergence (EPOST) or postemergence (POST) imazethapyr treatments at 71 g ai/ha as a foliar, soil, or foliar + soil application was also evaluated. Imazethapyr placement above or below the nutsedge tuber generally increased shoot number, shoot dry weight (SW), shoot regrowth dry weight (SRW), and root tuber dry weight (RTW) production in both species, 28 and 42 days after treatment (DAT) compared with the control. However, the 5-cm above + 5-cm below tuber treatment at 14, 28, and 42 DAT reduced purple nutsedge shoot number, SW, SRW, and RTW to 19, 7, 14, and 26% of the control, respectively. Yellow nutsedge shoot number was 103% of the control with the 5-cm above + 5-cm below tuber treatment 42 DAT. The 5-cm above + 5-cm below tuber treatment reduced yellow nutsedge SW, SRW, and RTW to 43, 44, and 23% of the control, respectively, 28 and 42 DAT. EPOST and POST foliar + soil and soil-only applications reduced SW 28 d after treatment (DAT) to 13% or less of the control for both species. SRWs of both species were ≤ 53% of the control 42 DAT for the soil-only application. The foliar-only treatment was the least effective in SW, SRW, and RTW reductions.

Greenhouse studies were conducted to determine the response of purple and yellow nutsedge to selective soil placement of 5 cm of soil treated with MON-12037 above and/or below the nutsedge tubers. MON-12037 at 53 g/ai ha applied as a foliar, soil, or foliar + soil application also were evaluated. MON-12037 placement above, below, or above + below the nutsedge tuber decreased shoot number, shoot dry weight, shoot regrowth dry weight, and root-tuber dry weight production in both species, 30 and 60 d after treatment. MON-12037 applied as a foliar, soil, and foliar + soil treatment was effective in reducing purple nutsedge shoot regrowth dry weight to less than 5% of the non-treated control. Yellow nutsedge shoot regrowth dry weight from the foliar + soil and soil-only applications was less than 1% of the non-treated control.

Greenhouse studies were conducted to determine the response of purple and yellow nutsedge to selective placement of 5 cm of soil treated with AC 263,222 above and/or below nutsedge tubers. AC 263,222 applied early POST (EPOST) or POST at 71 g ai ha-1 as a foliar, soil, or foliar + soil application also was evaluated. AC 263,222 applied below nutsedge tubers did not reduce purple or yellow nutsedge shoot number, shoot dry weight, shoot regrowth dry weight, or root-tuber dry weight. However, when it was applied above purple nutsedge tubers, shoot dry weight was reduced; and when it was applied above yellow nutsedge tubers, shoot dry weight and root dry weight were reduced. AC 263,222 applied 5 cm above + 5 cm below purple nutsedge tubers reduced shoot number, shoot dry weight, shoot regrowth dry weight, and root dry weight to 9, 4, 10, and 16% of the control, respectively, in purple nutsedge and to 23, 16, 9, and 15% of the control, respectively, in yellow nutsedge. AC 263,222 applied EPOST or POST reduced shoot dry weight, shoot regrowth dry weight, and root dry weight of purple nutsedge to less than or equal to 11, 7, and 27% of the control, respectively, and to less than or equal to 10, 16, and 29% of the control, respectively, for yellow nutsedge with no differences between application methods. The foliar and soil activity of AC 263,222 for purple and yellow nutsedge control provides an advantage over currently registered peanut herbicides.

Greenhouse studies were conducted to determine yellow nutsedge response to selective placement of a 5-cm layer of norflurazon-treated soil above, below, or above plus below pregerminated nutsedge tubers. Norflurazon at 1.68 kg ai/ha applied postemergence (POST) as a foliar, soil, or foliar plus soil treatment was also evaluated. Soil concentrations of norflurazon at 1.5 mg/kg (w/w) applied below or above plus below nutsedge tubers reduced yellow nutsedge shoot numbers at least 69%, shoot height at least 71%, shoot dry weights at least 77%, and root tuber dry weights at least 89%. Yellow nutsedge growth reduction with norflurazon was greatest when norflurazon was placed in the soil profile below or above plus below the yellow nutsedge tubers. Placement of norflurazon above yellow nutsedge tubers did not reduce shoot number, height, or dry weight until the foliar portion of plants were removed 39 d after treatment. POST application of norflurazon did not reduce initial yellow nutsedge shoot number regardless of application method. Foliar-only POST application of norflurazon was less effective for reducing numbers of emerged yellow nutsedge than application to soil only or soil plus foliage.

Tomato rootstocks have been successfully used for eggplant production. However, the safety of herbicides registered in tomato has not been tested on grafted eggplant, which is a combination of tomato rootstock and eggplant scion. Greenhouse and field experiments were conducted to determine response of grafted eggplant on tomato rootstock to napropamide, metribuzin, halosulfuron, trifluralin, S-metolachlor, and fomesafen herbicides. In greenhouse experiments, herbicide treatments included pretransplant S-metolachlor (400 and 800 g ai ha−1), pre- or posttransplant metribuzin (140 and 280 g ai ha−1), and posttransplant halosulfuron (18 and 36 g ai ha−1). In field experiments, herbicide treatments included pretransplant fomesafen (280 and 420 g ai ha−1), halosulfuron (39 and 52 g ha−1), metribuzin (280 and 550 g ha−1), napropamide (1,120 and 2,240 g ai ha−1), S-metolachlor (800 and 1,060 g ha−1), and trifluralin (560 and 840 g ai ha−1). The eggplant cultivar ‘Santana' was used as the scion and nongrafted control, and two hybrid tomatoes ‘RST-04−106-T' and ‘Maxifort' were used as rootstocks for grafted plants. In both greenhouse and field experiments, there was no difference between grafted and nongrafted eggplant in terms of injury caused by herbicides. Metribuzin posttransplant at 140 and 280 g ha−1 caused 94 and 100% injury to grafted and nongrafted eggplant 4 wk after treatment. In field experiments, pretransplant fomesafen, napropamide, S-metolachlor, and trifluralin caused less than 10% injury and no yield reduction in grafted and nongrafted eggplant. However, metribuzin caused injury and yield reduction in both grafted and nongrafted eggplant. Metribuzin at 550 g ha−1 caused 60 and 81% plant stand loss in 2013 and 2014, respectively. Halosulfuron reduced yield 24% in both grafted and nongrafted eggplant compared to nontreated control in 2013 but did not reduce yield in 2014. The pretransplant S-metolachlor, napropamide, fomesafen, and trifluralin are safe to use on eggplant grafted onto tomato rootstock, and will be a valuable addition to the toolkit of eggplant growers.

Greenhouse and field studies were conducted to determine tolerance of tomato to halosulfuron, imazosulfuron, and trifloxysulfuron herbicides applied through drip irrigation. In greenhouse studies, PRE- and POST-applied trifloxysulfuron caused greater tomato injury (14 and 54% injury, respectively) than PRE- and POST-applied halosulfuron (5 and 26% injury, respectively) or imazosulfuron (5 and 23% injury, respectively). All herbicide treatments in the greenhouse studies caused greater injury to tomato than the nontreated. Greater tomato injury was observed in the greenhouse from herbicides applied POST than when soil applied. Tomato injury from POST-applied halosulfuron, imazosulfuron, or trifloxysulfuron followed a linear relationship, with tomato injury increasing with increasing herbicide rate. Tomato photosynthetic rate did not differ among the herbicide treatments (32.7 to 55.0 μmol m−2 s−1) and the nontreated (38.0 to 55.0 μmol m−2 s−1). At 5 to 16 days after treatment (DAT), tomato treated with imazosulfuron POST (0.26 to 0.46 cm s−1) or trifloxysulfuron POST (0.27 to 0.51 cm s−1) had lower stomatal conductance compared to the stomatal conductance of the nontreated tomato (0.65 to 0.76 cm s−1). Chlorophyll content did not differ among treatments at 0 to 6 DAT. At 7 to 12 DAT, tomato treated with imazosulfuron POST (34.0 to 40.1 SPAD) and trifloxysulfuron POST (35.0 to 41.6 SPAD) had lower chlorophyll content compared to the nontreated (39.1 to 48.1 SPAD). In 2008 and 2009 field studies, no tomato injury was observed. Herbicide, herbicide application method, and herbicide rate had no effect on tomato height (73 to 77 cm 14 DAT, 79 to 84 cm 21 DAT) and total fruit yield (62,722 to 80,328 kg ha−1).

Drip irrigation is installed under polyethylene mulch to supply irrigation and nutrients to vegetables grown in plasticulture. This irrigation system also provides an alternative method for application of herbicides into the plant bed for control of yellow and purple nutsedge. Greenhouse and field studies were conducted to determine bell pepper tolerance to halosulfuron, imazosulfuron, and trifloxysulfuron applied POST (over the top of pepper in greenhouse study, POST-directed in the field study) or soil applied (applied by hand with water in greenhouse study or through drip irrigation in the field study). In greenhouse studies, pepper injury from halosulfuron, imazosulfuron, and trifloxysulfuron applied POST was similar at 14 and 21 d after treatment (DAT; 21 to 35% and 54 to 60%, respectively). Halosulfuron, imazosulfuron, and trifloxysulfuron soil applied in greenhouse studies caused 6 to 8% and 13 to 20% injury to pepper at 14 and 21 DAT, respectively. Pepper injury in greenhouse studies increased as rate of halosulfuron, imazosulfuron, and trifloxysulfuron increased regardless of application method (soil or POST applied). Dry pepper weight at 28 DAT followed an inverse linear response to increasing rates of halosulfuron, imazosulfuron, and trifloxysulfuron. In field studies, bell pepper height among herbicide treatments ranged from 32 to 37 cm at 14 DAT and was not different from the nontreated check (36 cm). Number one grade (7.8 to 14.7 MT ha−1) and fancy grade (2.1 to 2.8 MT ha−1) pepper fruit yield was not different in herbicide-treated pepper compared with yield of pepper in the nontreated check (10.0 to 26.6 MT ha−1, respectively). Based on these studies, pepper has excellent crop tolerance to halosulfuron, imazosulfuron, and trifloxysulfuron applied through drip irrigation or POST-directed but is not tolerant to POST applications.