Glasshouse studies were undertaken to determine the effect of imposed moisture stress on the phytotoxicity of haloxyfop; the absorption, translocation, and metabolism of14C-haloxyfop; and14C-photoassimilate partitioning in johnsongrass and large crabgrass. Following foliar applications of haloxyfop at 30 and 25 g ai ha–1to large crabgrass and johnsongrass, respectively, control 15 days after treatment was 92% for nonstressed plants and less than 12% for water-stressed plants. Foliar absorption of14C-haloxyfop was reduced by moisture stress 1, 3, 5, and 24 h after treatment (HAT) in large crabgrass and 1, 3, 5, 48, and 72 HAT in johnsongrass. Regardless of stress treatment, absorption in both species reached a maximum by 24 HAT. Translocation of the radiolabel from the treated leaf to plant parts above and below the node of the treated leaf was inhibited by moisture stress in large crabgrass and johnsongrass at all harvest intervals beginning 5 and 24 HAT, respectively. Metabolism of14C-haloxyfop was not altered by moisture stress. Fixation of14CO2and subsequent distribution of the14C-photoassimilates were reduced by moisture stress. Decreases in photoassimilate translocation were similar to reductions in14C-haloxyfop translocation. Moisture stress reduced the phytotoxicity of haloxyfop in the two grasses, and the reduced activity of haloxyfop appeared to be partially related to changes in herbicide absorption and translocation.

Single and sequential applications of mefluidide {N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl] amino] phenyl] acetamide} and acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} were evaluated in the field for velvetleaf (Abutilon theophrastiMedic. ♯ ABUTH) and common cocklebur (Xanthium pensylvanicumWallr. ♯ XANPE) control in soybeans [Glycine max(L.) Merr. ‘Williams’]. Acifluorfen was applied at 0.4 or 0.6 kg ai/ha alone or 3, 5, or 7 days following application of 0.1 or 0.3 kg ai/ha mefluidide. Acifluorfen applied alone provided acceptable control of velvetleaf and common cocklebur in the two- and three-leaf stage of growth, but acifluorfen was not as effective when applied to weeds with five to eight true leaves. Sequential applications of mefluidide and acifluorfen often increased velvetleaf and common cocklebur control, compared to either herbicide applied alone.

Summary: Résumé: Zusammenfassung Separate field experiments were conducted to evaluate Sorghum halepense (L.) Pers. (johnson‐grass) control with foliar‐applied herbicides in soyabeans (Glycine max (L.) Merr. cv. Williams) grown in tilled (mould board plough) or no‐tillage fields. Fluazifop‐butyl, sethoxydim, CGA‐82725 and mefluidide were applied post‐emergence to 45‐cm high S. halepense and glyphosate was applied with a wick bar to 90‐cm high S. halepense in the conventional and no‐tillage studies. HOE‐00581 {ethyl 2‐[4‐[(6‐chloro‐2‐benzoazolyl)oxyl]‐phenoxy]propanoate} was applied to 45‐cm high S. halepense only in the no‐tillage studies. Fluazifop‐butyl, sethoxydim, CGA‐82725, HOE‐00581 (no‐tillage only) and glyphosate provided good control of S. halepense in conventional and no‐tillage soyabeans and generally increased soyabean yields compared to weedy controls, when low precipitation was not limiting yields. Mefluidide at 0.3 kg ai ha−1 provided the least S. halepense control in the conventional and no‐tillage studies. The studies were not designed to compare S. halepense control in the two tillage systems; however, these data show that tillage to disrupt S. halepense rhizomes was not required to obtain good control of S. halepense with foliar applications of fluazifop‐butyl, sethoxydim, CGA‐82725, HOE‐00581 and glyphosate. La lutte contre Sorghum halepense (L.) Pers. utilisant des herbicides foliaires dans le soja en culture classique et en non‐culture Plusieurs essais ont été installés sur le terrain dans le but d'évaluer des herbicides foliaires pour la destruction de Sorghum halepense (L.) Pers. dans le soja (Glycine max (L.) Merr. var. Williams) cultivé en terre labourée et en non‐culture. Le fluazifop‐butyle, le séthoxydime, le CGA‐82725 et le méfluidide ont été appliqués en postlevée sur S. halepense haut de 45 cm et le glyphosate a été appliqué sur S. halepense haut de 90 cm, utilisant un frotteur, dans les deux sytèmes de culture. HOE‐00581 (éthyle 2‐[4‐[(6‐chloro‐2‐benzoazolyl)oxyl]phénoxy]propanoate) a été appliqué sur S. halepense haut de 45 cm uniquement dans les systèmes de·non‐culture. Le fluazifop‐butyle, le séthoxydime, le CGA‐82725, le HOE‐00581 et le glyphosate ont bien maitriséS. halepense dans les deux systèmes de culture du soja, tout en augmentant les rendements de soja par rapport au témoin enherbé, là où une précipitation insuffisante n'est pas intervenue. Le méfluidide à 0,3 kg ai ha−1 a donné la plus faible destruction de S. halepense en culture classique et en non‐culture. Une comparaison de la destruction de S. halepense dans les deux systèmes de culture n'était pas le but principal de ces travaux; cependant ces données font voir qu'un labourage pour briser les rhizomes de S. halepense n'est pas de rigueur pour obtenir une bonne maîtrise de l'adventice par des applications foliaires de fluazifop‐butyle, séthoxydime, CGA‐82725, HOE‐00581 et glyphosate. Sorghum halepense (L.) Pers. Bekämpfung mit blattwirksamen Herbiziden in Soyakulturen mit und ohne Bodenbearbeitung Es wurden sepa...

Effects of fluazifop-butyl {(±)-butyl 2-[4-[(5-(trifluoromethyl)-2-pyridinyl)oxy] phenoxy] propanoate} on cellular uptake and incorporation of14C-leucine,14C-uridine, and14C-thymidine into protein, RNA, and DNA, respectively, were evaluated in corn (Zea maysL.) coleoptiles and soybean [Glycine max(L.) Merr.] hypocotyls. Uptake of14C-leucine in corn coleoptiles was inhibited by fluazifop-butyl at 10-4to 10-7M, which was related to reductions in incorporation of14C-leucine into protein at 10-4to 10-6M. The effect of fluazifop-butyl on14C-leucine uptake and incorporation was reduced by 2 × 10-6M 2,4-D [(2,4-dichlorophenoxy)acetic acid], indicating antagonism between these herbicides. RNA and DNA synthesis were inhibited at 10-5and 10-4M. Protein synthesis in soybean hypocotyls was stimulated by 10-7and 10-6M fluazifop-butyl 33 and 27%, respectively, and inhibited by 10-4M 50%. RNA and DNA synthesis were also inhibited by 10-4M in soybean.

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