Effect of weed growth stage and adjuvant on the efficacy of fomesafen and bentazon

Abstract

The efficacies of bentazon and fomesafen in controlling annual weeds in dry and edible pod beans in New York State were investigated in greenhouse and field experiments. Dose responses to bentazon and fomesafen were studied for four weed species (ragweed, velvetleaf, eastern black nightshade, and hairy nightshade) under greenhouse conditions. Herbicides were applied at cotyledon to two-, two- to four-, and four- to six–true leaf stages, both with and without a crop oil concentrate (bentazon) or a nonionic surfactant (fomesafen). Field studies were conducted for 2 yr for all weed species except eastern black nightshade, for which no adequate field populations were found. Field studies confirmed greenhouse results, indicating that weed control could be improved by the use of an adjuvant, but there were exceptions. In general, adjuvant usage improved the efficacy of fomesafen more than it did with bentazon. The minimum rates of herbicide required for effective and consistent control was dependent on the particular combination of weed species, herbicide and its rate of application, growth stage at which the application was made, and adjuvant usage.

Alkyl Ether Sulfate Improves Efficacy of Herbicides Against Common Goosefoot and Field Bindweed in Wheat

“…Furthermore, these results were also in accordance with those of Han and Tao (2011), who mentioned that adjuvant addition enhanced fomesafen efficacy, thereby effectively controlling weeds. Differences in the activity of herbicides that were observed among the study weeds may be due to differences in the retention and/or uptake of the herbicides, probably as a result of differences in branching habit, cuticle and leaf area ratio (Hess and Foy, 2000;Bellinder et al, 2003).…”

Farmers' perspective on herbicide‐resistant weeds and application of resistance management strategies: results from a German survey

“…In addition to being a result of herbicide resistance, a low efficacy of herbicide treatments can be caused by various other factors. Adverse environmental conditions, suboptimal growth stage of the target weed species at the time of spraying or unsuitable dose rates of the applied herbicide product may also result in the survival of individual weeds or weed populations . In order to confirm herbicide resistance as a cause for reduced herbicidal efficacy, farmers can take different approaches for confirming the presence of herbicide resistance in their weed populations.…”

The Effect of Sugar Beet Broadleaf Herbicides on Fluorescence Induction Curves in Amaranthus retroflexus L. and Portulaca oleracea L.

“…Streibig (2005, 2007) depicted that the inhibition of photosynthesis by desmedipham and phenmedipham is raised in the high post-spray light intensity than low light intensities. Bellinder et al (2003) pointed out that successful control using herbicide rates depended critically on current environmental conditions. Therefore, it appears that the different ED50 or ED90 values caused by desmedipham + phenmedipham + ethofumesate, chloridazon and clopyralid were due to the variation in light and temperature conditions of both species.…”