Fall applications of fenarimol on hybrid Bermudagrass (Cynodon dactylon × C. transvaalensis) provide effective preemergence Poa annua (L.) control and suppress Ophiosphaerella spp. pathogens; however, concerns exist for turf injury and root growth restrictions. Two 60-d greenhouse studies were conducted to evaluate the effects of fenarimol at 0, 1.6, and 3.2 kg ai/ha per 30 d with and without trinexapac-ethyl (TE) at 0.017 kg ai ha/15 d on ‘TifEagle’ Bermudagrass. Turf color was enhanced by TE 14 d after initial treatment (DAIT) and was continually superior throughout the experiment. Fenarimol at 3.2 kg/ha per 30 d decreased turf color 14 DAIT, but was similar to nontreated turf on all other observation dates. Increased fenarimol rates applied twice caused approximately 10% injury at 42, 49, and 56 d after treatment; however, injury was acceptable after initial and repeat applications. TE reduced clipping yield an average 39% from six sampling dates. Initial fenarimol applications (without TE) reduced clippings by 37% 20 DAIT and repeated applications reduced clippings 40, 50, and 60 DAIT. Increased fenarimol rate linearly decreased root mass for turf treated with and without TE; however, Bermudagrass receiving TE averaged 23% enhanced root mass 60 DAIT over all fenarimol rates. Bermudagrass receiving fenarimol at 0, 1.6, and 3.2 kg/ ha per 30 d with TE averaged 27, 24, and 16% higher root mass, respectively, compared to turf receiving fenarimol without TE. Treatments had no influence on root length. Results indicate that two consecutive fenarimol applications at 1.6 and 3.2 kg/ha per 30 d may cause minor injury to TifEagle Bermudagrass and restrict root growth. Repeated TE applications, however, could decrease injury from fenarimol and enhance rooting relative to fenarimol applied exclusively.

Field studies were conducted at three locations to evaluate glyphosate-resistant (GR) cotton response, weed control, and cotton lint yields to two formulations of glyphosate (diammonium salt– glyphosate and isopropylamine salt–glyphosate) and trifloxysulfuron applied early postemergence (EPOST) alone or to tank mixtures of trifloxysulfuron with each glyphosate formulation, with and without a late postemergence-directed (LAYBY) treatment of prometryn plus MSMA. Trifloxysulfuron and both formulations of glyphosate controlled common lambsquarters and pitted morningglory. Both glyphosate formulations provided equivalent control of common lambsquarters, goosegrass, pitted morningglory, prickly sida, and smooth pigweed. Trifloxysulfuron controlled smooth pigweed better than either glyphosate formulation but did not control goosegrass or prickly sida. Prometryn plus MSMA LAYBY improved late-season control of common lambsquarters, goosegrass, large crabgrass, and pitted morningglory for all EPOST systems and improved late-season smooth pigweed control for EPOST systems that did not include trifloxysulfuron. Cotton injury was 2% or less from both glyphosate formulations, while trifloxysulfuron injured ‘Deltapine 5415RR’ 7 to 16% at two locations. At a third location, trifloxysulfuron injured ‘Paymaster 1218RR/BG’ 24%, and when applied in mixture with either glyphosate formulation, injury increased to at least 72%. Cotton injury was transient at the first two locations and was not visually apparent 3 to 5 wk later. Cotton yield at the third location was reduced. High cotton yields reflected high levels of weed control.

In the state of Illinois, waterhemp and smooth pigweed are among the worst agricultural weeds. Previous research shows high potential for hybridization between these two species. However, the actual occurrence of hybrids in natural settings is still uncertain. Morphological similarity between hybrids and waterhemp makes field surveys of hybrids difficult to conduct. The main purpose of this study was to characterize the morphology of waterhemp × smooth pigweed F1 hybrids, emphasizing evaluation of characters that may allow for hybrid discrimination in field Amaranthus communities. Concurrently, the study characterized hybrid reproductive fitness, chromosome number, and DNA content. To accomplish this, hybrids were obtained from field crosses. A species-specific polymorphism in the ALS gene was used to verify hybrid identity. Significant differences (α = 0.05) between hybrids and individuals of the parental species were observed for five staminate and five carpellate characters. Of these, five characters differentiated hybrids from waterhemp. However, clustering analyses using these characters indicated that morphological differences were not reliable enough, by themselves, for unambiguous hybrid identification. Also, hybrid homoploidy (2n = 32) with respect to parental species excluded chromosome counts in hybridity determinations. However, DNA content analysis may be used for such purpose. Hybrids had an average of 1.21 pg of DNA per 2C nucleus, a value intermediate to that of parental species. Hybrids produced 3.3 or 0.7% the seed output of parental and sibling waterhemp individuals, respectively. Percent micropollen in hybrids was 95-times greater than in parental species. Hybrid sterility appears to be the most reliable feature for hybrid discrimination when conducting field surveys. However, molecular and cytogenetic analyses as employed in this study may be desired for ultimate identity corroboration.

Field experiments were conducted at Hays and Manhattan, KS, in 2002 and 2003 to determine winter wheat response to simulated drift rates of glyphosate and imazamox. Glyphosate and imazamox at 1/100×, 1/33×, 1/10×, and 1/3× of usage rates of 840 g ae/ha glyphosate and 35 g/ha imzamox were applied individually to wheat in the early jointing or the early flower stages of growth. Wheat injury and yield loss increased as herbicide rate was increased, with minimal effect from either herbicide at the 1/100× rate, and nearly complete kill and yield loss of wheat from both herbicides applied at the 1/3× rate, regardless of growth stage at application. In general, wheat injury and yield reduction were greater from glyphosate than from imazamox. In addition, wheat injury and yield loss were greater from herbicide treatment at the jointing stage than at the flowering stage of development. Correlation analysis suggests that visual injury is an accurate indicator of yield reductions. Germination tests of harvested grain showed that the viability of the wheat seed was not reduced if plants survived the herbicide treatment and produced a harvestable seed.

Perennial pepperweed is an invasive weed spreading rapidly throughout a wide range of habitats in the western United States. This study was designed to test whether integrating early season mowing with a systemic herbicide application would improve the control of perennial pepperweed. Experiments were conducted within three different environments including high desert, roadside, and floodplain areas. In treatments not mowed, chlorsulfuron at 0.104 kg ai/ha reduced perennial pepperweed biomass and density by 100%, whereas applications of 2,4-D at 2.11 kg ae/ha and glyphosate at 3.33 kg ae/ha were inconsistent and did not provide effective control. Mowing alone did not reduce perennial pepperweed biomass or density the following year, but mowing followed by application of a herbicide treatment to resprouting plants reduced biomass at all three sites compared with nonmowed treatments including herbicides. Among combinations of mowing and herbicides, chlorsulfuron at 0.052 kg/ha reduced perennial pepperweed biomass by >99% at all three sites, and glyphosate at 3.33 kg/ha reduced biomass by ≥80% at two sites 1 yr after applications. The effectiveness of glyphosate at 3.33 kg/ha in combination with mowing provides land managers with a valuable control option for perennial pepperweed in wetland or riparian areas where chlorsulfuron is not registered for use.

Field studies were conducted from 2000 to 2003 to determine the effectiveness of potato desiccants for late-season hairy nightshade control and also their effect on hairy nightshade seed germination. Commercial sulfuric acid at 280 L/ha controlled 94 to 99% of the hairy nightshade 1 wk after treatment (WAT) in all years. Diquat at 560 g/ha and glufosinate-ammonium at 420 g/ha provided at least 93% control 1 WAT in all years except 2003 when control did not exceed 72%. By 3 WAT, hairy nightshade control ranged from 93 to 100% for all treatments, including carfentrazone-ethyl at 56 g/ha, diquat at 420 g/ha, paraquat at 530 g/ha, and sulfuric acid (proprietary process) at 280 L/ha. Treatment of plants with desiccants did not affect germination of hairy nightshade seed, with the exception of a 7% reduction in germination by the higher rate of diquat in 2001 and 2002.

Crop yield and weed control rating have been used to measure weed and crop response to weed management treatments, eliminate unacceptable weed management treatments, and select “best” treatments for recommendation to farmers. However, the mathematical relationship between crop yield and rated weed control has not been reported before from such treated screening experiments. Likewise, differences have not been reported before in rated weed control among experienced observers (i.e., reliability) when rating the same experiments and for an experienced observer over time (i.e., repeatability). Data from published experiments on zone herbicide application in field corn in which weeds reduced yield to various amounts were reanalyzed to examine these issues. For this study, relative corn yield was calculated as a percentage of the 1× broadcast herbicide rate for two observers and either three experimental site-years or their average. For observer A, relative corn yield (%) increased linearly as rated total weed control (%) increased for all 3 site-yr and their average. For observer B, equations were curvilinear in 2 of 3 site-yr. For both observers, equations accounted for little data variability in relative corn yield (r2 = 0.25 and 0.25 in site-year 1, respectively, 0.38 and 0.36 in site-year 2, 0.58 and 0.57 in site-year 3, and 0.43 and 0.42 for their average). When rated total weed control by observer A was graphed against that of observer B, the relationship was a nearly ideal 1:1 linear relationship in only 1 of 3 site-yr. In two other site-years, equations were nonlinear, indicating that one observer distinguished smaller differences between treatments at lower rated control than the other observer. Between-row total weed cover and in-row total weed height influenced observer weed control rating.

Tall ironweed is a troublesome perennial weed that infests cool-season grass pastures in Kentucky. Field experiments were conducted in 2000 through 2003 to evaluate the efficacy of fall-applied herbicides on established tall ironweed following a midsummer mowing. Triclopyr-containing treatments showed the greatest suppression of tall ironweed 12 mo after treatment (MAT), across all years. With triclopyr at 0.56 and 0.63 kg/ha, tall ironweed control was 80% or greater in 2 of the 3 yr. Dicamba initially provided 87% control 8 MAT in 2 of 3 yr and declined to less than 60% 12 MAT. Tall ironweed shoot density was also reduced 66% or more 12 MAT with fall-applied triclopyr-containing treatments. In contrast, tall ironweed density increased approximately twofold in dicamba-treated plots between 8 to 12 MAT in all 3 yr. The impact of herbicide treatment on dry matter (DM) yield of spring-seeded red clover (Trifolium pratense L.), tall ironweed, and forage grasses was also evaluated. Red clover DM yield in the herbicide-treated plots in 2002 showed no significant differences from the untreated control. However, red clover DM yield in 2003 was lowest for the two triclopyr + clopyralid treatments, indicating a decrease in DM production compared with that of the nontreated control. Results indicated that fall-applied triclopyr-containing herbicides following a midsummer mowing is an effective program for removing tall ironweed from grass pastures, but further research is needed to evaluate the establishment of red clover following herbicide treatment.

Sand stockpiles, located near commercial cranberry beds in Massachusetts, New Jersey, Washington, and Wisconsin, were sampled quarterly over a 2-yr period. Samples were collected from the surface and the interior of the piles. Utilizing a simple greenhouse germination bioassay, 74 plant species representing 23 plant families were identified across all locations and samples. Plant density varied by region and by sampling depth; species richness varied by region only. More seedlings germinated from samples taken from the surface of the stockpile compared with interior samples. Almost half of all species detected in either surface or interior samples were represented by only one seedling. Fifty-nine percent of the plant species from Massachusetts and New Jersey samples, and 79% and 96% of the plant species from Wisconsin and Washington, respectively, were considered to be weeds in cranberry production. Only one-third of the identified species had wind-blown seeds; seed dispersal was by other mechanisms in almost half of the species. This survey documented the weed management implications of spreading stockpiled sand on cranberry bogs for horticultural or pest management purposes. To minimize the introduction of additional weed problems, growers and integrated pest management consultants should evaluate the seedbank potential of a stockpile prior to application of the sand to the production area.

Sunflower lines developed to resist some acetolactate synthase (ALS)-inhibiting herbicides are susceptible to foliar applications of other ALS-inhibiting herbicides. Research was conducted to determine whether imidazolinone (IMI)- or sulfonylurea (SU)-resistant sunflower was affected by soil residues of imazethapyr, metsulfuron, or flucarbazone. In greenhouse experiments, IMI-sunflower displayed 60 and 66% injury 4 wk after emergence with incorporated soil residues of metsulfuron at 4.2 g ai/ha and flucarbazone at 30 g ai/ha, respectively, but response to imazethapyr at 35 g ai/ ha was not different from that of nontreated plants. Metsulfuron at 4.2 g/ha and flucarbazone at 30 g/ha resulted in 56 and 72% less biomass accumulation, respectively, of IMI-sunflower compared with that of nontreated plants. Incorporated soil residues of imazethapyr, metsulfuron, or flucarbazone did not cause significant injury or result in shorter plants or less biomass accumulation of SU-sunflower than nontreated sunflower in greenhouse experiments. In field experiments, nonincorporated residues of imazethapyr, metsulfuron, or flucarbazone did not induce visible chlorosis or significant stunting of IMI- or SU-sunflower compared with nontreated sunflower. Herbicide-resistant sunflower growing in soil with nonincorporated residues of imazethapyr, metsulfuron, or flucarbazone produced seed yield similar to sunflower growing in sulfentrazone-treated soil or nontreated soil.

Soil-residual herbicides can be applied to the soil under grapevines during fall or spring before weed emergence. But, early spring moisture and warm weather conditions may enhance weed emergence before spring herbicide applications. Therefore, fall application of herbicide can be useful if the herbicides provide adequate weed control the following spring and summer. Fall and spring applications of oryzalin or norflurazon, applied alone or in combination with diuron, simazine, or oxyfluorfen, were evaluated for weed control in grape at Oskaloosa and Eudora in northeast Kansas in the 2002 to 2003 and 2003 to 2004 growing seasons. Weeds were not controlled adequately with oryzalin or norflurazon applied alone. At the end of the growing season, weed control was 10 to 20% greater when herbicides were applied in the spring than when applied in the fall. In addition, weed control with norflurazon was slightly greater than with oryzalin. In general, norflurazon or oryzalin applied in combination with simazine, diuron, or oxyfluorfen gave greater weed control than norflurazon or oryzalin applied alone. The greatest control was with norflurazon or oryzalin applied with oxyfluorfen. In general, all herbicide combinations provided similar weed control 4 mo after spring treatment in 2003 and 3 mo after spring treatment in 2004. This study showed that acceptable weed control can be achieved when norflurazon or oryzalin is applied with oxyfluorfen or diuron in the fall.

Experiments were conducted in weed-free environments to determine corn tolerance to trifloxysulfuron applied PRE or POST, and to determine the potential for trifloxysulfuron applied PRE or POST to cotton to injure corn grown in rotation the following year. Trifloxysulfuron at 3.75, 7.5, or 15 g ai/ha applied PRE or POST resulted in 98% stand reduction of imidazolinone-tolerant (IT) corn and 100% stand reduction in conventional corn. No injury occurred to imidazolinone-resistant (IR) corn. A corn cultivar yield response was observed, with conventional nontreated corn yielding 8,850 kg/ha and greater than nontreated IT corn at 7,900 kg/ha. Nontreated IR corn yielded the least, at 6,400 kg/ha, and these yields were equivalent to trifloxysulfuron-treated IR corn at 6,590 kg/ha. Cotton treated with trifloxysulfuron PRE at any rate was injured less than 8%. Both trifloxysulfuron at 7.5 g/ha POST and pyrithiobac at 70 g ai/ha POST injured cotton 11% early in the season. Neither trifloxysulfuron nor pyrithiobac influenced weed-free cotton lint yields. When grown in rotation, corn was not injured by trifloxysulfuron or pyrithiobac applied the previous year to cotton, and yields were not influenced.

Glyphosate-resistant corn was no-till planted into alfalfa that was in the early bud stage (UNCUT) or had been cut 3 to 4 d earlier and baled for hay (CUT). Alfalfa control and corn yield were measured in nontreated plots as well as plots treated with glyphosate alone or tank-mixed with 2,4-D or dicamba applied at planting (AP) or POST. Alfalfa control was greater for all AP treatments of UNCUT compared to CUT alfalfa. Glyphosate plus dicamba applied AP controlled alfalfa better than the other AP treatments resulting in increased corn yield compared with other AP treatments. Postemergence applications of glyphosate alone or tank-mixed with 2,4-D or dicamba controlled alfalfa better 6 weeks after treatment than AP applications of the same herbicides; however, corn yield for AP treatments were similar or greater than the yield of POST applications of the same herbicides. Corn yield averaged 13% higher following herbicide applications to UNCUT compared with CUT alfalfa, so the value of alfalfa hay must be weighed against the loss of corn yield when making decisions concerning the management of an alfalfa–corn rotation.

Giant smutgrass is a perennial, clump-type, grassy weed that commonly infests Florida pastures. Experiments were conducted in 1998 and 1999 in Immokalee, FL, to evaluate multiple mowing treatments in combination with hexazinone applications at 0.56 to 1.7 kg ai/ha, to control giant smutgrass and bahiagrass density. Mowing did not influence giant smutgrass control in 1998 or 1999. Hexazinone application increased giant smutgrass control at all application rates. In 1998, regression analysis determined that hexazinone applied at 0.56 kg/ha provided >90% control of giant smutgrass 182 d after treatment (DAT) and >80% control 321 DAT. Both 1.1 and 1.7 kg/ha of hexazinone provided >90% control for 365 DAT in 1998. In 1999, due in part to excessive rainfall, 0.56 kg/ha provided >80% control for only 48 DAT. It was also concluded that application rates of 0.83 to 0.98 kg/ha hexazinone were the lowest rates that consistently provided 80% or better control over both years. From 0 to 30 DAT, bahiagrass density increased by 17% for the 0.56 kg/ha rate and 2% at the 1.7 kg/ha rate. From 30 to 365 DAT, bahiagrass density increased at 0.04% per day compared with 0.1% per day for 0.56 and 1.7 kg/ha, respectively. Increased bahiagrass injury by the higher application rates of hexazinone was responsible for low levels of bahiagrass growth from 0 to 30 DAT. However, bahiagrass soon recovered from injury, and the higher application rates resulted in a more rapid rate of bahiagrass spread, likely due to less competition of giant smutgrass in plots treated with 1.1 and 1.7 kg/ha rates. These data prove that mowing prior to hexazinone application is an unwarranted expense, and that the 1.1 kg/ha rate provided the most effective and consistent giant smutgrass control with acceptable levels of bahiagrass injury.

Several new herbicides have been registered for pasture weed control, but their effect on ‘Coastal’ bermudagrass dry matter (DM) yield has not been documented. The objective of this study was to determine the effect of clopyralid, fluroxypyr, imazapic, picloram, picloram + fluroxypyr, picloram + 2,4-D amine, triasulfuron + dicamba, triclopyr amine + clopyralid, triclopyr ester, triclopyr ester + fluroxypyr, trifloxysulfuron, 2,4-D amine + dicamba, and 2,4-D ester on Coastal bermudagrass yield. Total DM yields of Coastal bermudagrass were not reduced by 0.84 kg/ha clopyralid, 0.031 kg ai/ha triasulfuron + 0.44 kg ai/ha dicamba, 1.205 kg ai/kg 2,4-D amine + 0.42 kg/ha dicamba, and 2.31 kg/ha 2,4-D ester. Although 0.227 kg ai/ha picloram + 0.84 kg/ha 2,4-D amine, 0.945 kg ai/ha triclopyr amine + 0.315 kg ai/ha clopyralid, and 1.68 kg ai/ha triclopyr ester reduced Coastal bermudagrass DM yields in harvest 1, there was no cumulative loss in total production in either 2001 or 2002 with these herbicides compared with that of the nontreated control. Coastal bermudagrass total DM yields were reduced by 52% with 0.158 kg ai/ha imazapic when applied to dormant bermudagrass in 2001, and by 26% with 0.021 kg ai/ha trifloxysulfuron when applied to actively growing bermudagrass in 2001; however, neither herbicide reduced total cumulative yield in 2002. In 2001 and 2002, total DM yield was reduced by an average of 25% with 0.42 kg/ha fluroxypyr, by 45% with 0.105 kg/ha imazapic, by 57% with 0.158 kg/ha imazapic, by 65% with 0.21 kg/ha imazapic, by 25% with 0.56 kg/ha picloram, by 20% with 0.188 kg/ha picloram + 0.188 kg/ha fluroxypyr, and by 18% with 0.63 kg/ha triclopyr ester + 0.21 kg/ha fluroxypyr, when applied to actively growing Coastal bermudagrass.

Field experiments were conducted in 2001 through 2003 in Wooster, OH, to determine strawberry (Fragaria X ananassa) plant response to clopyralid applied after plant renovation in established plantings. Clopyralid applied at a rate of 200 g ae/ha or greater controlled at least 82% of common groundsel (Senecio vulgaris) 6 wk after treatment (WAT). Maximum total fruit yield (marketable plus unmarketable fruits) occurred at a clopyralid rate of 200 g/ha, and higher or lower rates resulted in reduced yield. Application of clopyralid at 400 g/ha tended to reduce the canopy of the strawberry crop, especially in comparison to rates lower that 200 g/ha. Overall, clopyralid applied POST at 200 g/ha did not reduce fruit yield when applied after strawberry renovation, and effectively controlled common groundsel plants that were entering the reproductive stage.

Protoporphyrinogen oxidase (protox)-inhibiting herbicides damage cell membranes, resulting in electrolyte leakage. A whole-plant dose-response study and a rapid assay that measured electrolyte leakage was used to determine the response of wild mustard, soybean, and protox inhibitor–susceptible and protox inhibitor–resistant common waterhemp to increasing doses of three protox inhibitors: acifluorfen, fomesafen, and sulfentrazone. For the dose-response study, whole plants were treated with the three protox-inhibitor herbicides. Electroconductivity assay 1 consisted of cutting discs from leaf tissue and submerging them in an incubation medium containing concentrations of acifluorfen, fomesafen, or sulfentrazone. In electroconductivity assay 2, the entire leaf was treated with solutions containing acifluorfen, fomesafen, or sulfentrazone. The whole-plant dose-response study showed increasing visible injury with increasing herbicide rates for all species and all herbicides. The order of visible injury was wild mustard > susceptible common waterhemp > resistant common waterhemp > soybean. In assay 1, electrolyte leakage from leaf discs treated with acifluorfen or fomesafen increased with increasing herbicide concentrations, and was similar for all species. In contrast, electrolyte leakage from leaf discs treated with sulfentrazone did not increase with increasing herbicide concentrations for any species. In assay 2, only wild mustard leaf discs increased in electrolyte leakage with increasing herbicide rates of acifluorfen, fomesafen, and sulfentrazone and followed the regression curves established by the whole-plant dose-response study. However, assay 2 was not able to distinguish between susceptible wild mustard and tolerant soybean, or between susceptible and resistant waterhemp.

Field research was conducted for 2 yr to evaluate response of corn and rice to simulated drift rates of a commercial premix of imazethapyr plus imazapyr [3:1 (w/w)]. Drift rates of the imazethapyr plus imazapyr premix represented 0.8, 1.6, 3.2, 6.3, and 12.5% of the usage rate of 63 g ai/ha (0.5, 1, 2, 4, and 7.9 g/ha, respectively). The imazethapyr plus imazapyr premix applied to six-leaf corn at 7.9 g/ha reduced height 11% compared with the nontreated control 7 days after treatment (DAT) but did not affect corn height 14 and 28 DAT. Corn yield was equivalent regardless of imazethapyr plus imazapyr rate and ranged from 10,200 to 11,500 kg/ha. At 28 DAT, rice height was reduced 12% when 7.9 g/ha of the imazethapyr plus imazapyr premix was applied early postemergence (EPOST) at two- to three-leaf and 14 and 5% when the imazethapyr plus imazapyr premix at 7.9 and 4 g/ha, respectively, was applied late postemergence (LPOST) at panicle differentiation. Reductions in mature rice height of 11 and 6% were observed when the imazethapyr plus imazapyr premix was applied LPOST at 7.9 and 4 g/ha, respectively, and a 5% reduction was observed for 7.9 g/ha of the imazethapyr plus imazapyr premix applied EPOST. Application of the imazethapyr plus imazapyr premix EPOST at 7.9 g/ha delayed heading in only 1 yr, but heading was delayed both years when applied LPOST. Rice yield was reduced 39 and 16% when the imazethapyr plus imazapyr premix was applied LPOST at 7.9 and 4 g/ha, respectively, compared with a 9% yield reduction for 7.9 g/ha applied EPOST.

Tolerance of eight market classes of dry beans (black, brown, cranberry, kidney, otebo, pinto, white, and yellow eye beans) to the PRE application of linuron at the rate of 2.25 and 4.50 kg ai/ha was studied at two locations in Ontario, Canada, in 2003 and 2004. The eight market classes differed in their response to linuron. Linuron PRE caused as much as 43, 20, 7, 17, 54, 36, 56, and 12% visual injury in black, brown, cranberry, kidney, otebo, pinto, white, and yellow eye beans, respectively. Linuron PRE at 2.25 kg/ha reduced plant height 38% in otebo beans and 31% in white beans. Linuron PRE at 4.50 kg/ha reduced plant height 24 to 56% in black, brown, otebo, pinto, and white beans. Shoot dry weight was reduced in otebo beans by 56% and in white beans, by 46% at the low rate. Shoot dry weight was decreased 26 to 92% in black, otebo, pinto, white, and yellow eye beans at the high rate. There were no differences in the shoot dry weight of the other market classes. Linuron PRE at the low rate reduced otebo bean yield 42% and at the high rate reduced yields by 56, 74, and 61% in black, otebo, and white beans, respectively. There was no effect on the yield of other market classes. Differences in dry bean market class tolerance to linuron exists and may be summarized for these cultivars as cranberry > kidney > brown > yellow eye > pinto > black > white > otebo. Additional research is needed to determine if cultivars within a dry bean market class differ in their response to linuron.

Annual bluegrass and roughstalk bluegrass are turfgrasses, but they can also be two of the most serious weed problems in highly maintained turfgrass. Ethofumesate has been used to control annual bluegrass; however, the results have been erratic, and ethofumesate is not widely utilized for annual bluegrass control in turfgrass. The objective of this research was to characterize the response of annual, roughstalk, and Kentucky bluegrasses and creeping bentgrass to a range of ethofumesate rates. Single applications of ethofumesate from 3.4 to 20.2 kg ai/ha were made to all four species during May of 1999 to 2001. All four species were injured from rates of ≥6.7 kg/ha. Roughstalk bluegrass was most injured by a single ethofumesate application. Percent roughstalk bluegrass control increased linearly with rate, and greater than 85% control was observed for rates of ≥16.8 kg/ha. In contrast, annual bluegrass showed almost no control, with rates ≤10.2 kg/ha, and the highest rate tested, 20.2 kg/ha, controlled only 47 to 62% of the annual bluegrass. Kentucky bluegrass was the least sensitive bluegrass species, with a maximum control of 3 to 15% from 20.2 kg/ha of ethofumesate. Creeping bentgrass was the least sensitive of the species tested, with low levels of control regardless of rate. During 3 yr of testing, maximum control of bentgrass from any rate was 4%. Single, high-rate applications of ethofumesate hold promise to control roughstalk bluegrass in creeping bentgrass turf. Sixteen Kentucky bluegrass cultivars used for low-cut athletic fields were evaluated for their tolerance to sequential ethofumesate applications during 1999 and 2002. The cultivars showed significant differences in ethofumesate tolerance, with ‘Moonlight’ and ‘America’ never showing any injury to sequential ethofumesate applications, while ‘Northstar’ and ‘Total Eclipse’ were severely injured.