Growth and electrophysiological studies in roots of intact diclofop-methyl susceptible and resistant seedlings were conducted to test the hypothesis that the herbicide acts primarily as a proton ionophore. The ester formulation of diclofop, at 0.2 micromolar, completely inhibited root growth in herbicide-susceptible oat (Avena sativa L.) after a 96 hour treatment, but induced only a delayed tra...

The fate and persistence of diclofop-methyl and diclofop in soil may be influenced by major processes such as chemical and biological degradation. In addition, losses in runoff occur because of its ability to adsorb strongly to soil particles. Up to 15% of diclofop-methyl is hydrolyzed at the time of application and incorporated into the soil, and as much as 85% is hydrolyzed within 24 h of app...

Electrophysiological measurements were made on the mesophyll cells of wheat (Triticum aestivum L. cv Waldron) and oat (Avena sativa L. cv Garry) coleoptiles treated either with the herbicide diclofop-methyl (methyl 2-(4-(2',4'-dichlorophenoxy)phenoxy)propanoate), or it's primary metabolite diclofop, (2-(4-(2',4'-dichlorophenoxy)phenoxy)-propanoic acid). Application of a 100 micromolar solution ...

Diclofop methyl, a commercial herbicide, was used as the sole carbon source to cultivate diclofop-degrading biofilms in continuous-flow slide culture. The biofilms were analyzed by using scanning confocal laser microscopy and image analysis. Spatial relationships among members of the community were distinctive to diclofop-grown biofilms. These relationships did not develop when the biofilms wer...

Field experiments were conducted in Virginia in 2000 and 2001 to investigate responses of wheat and diclofop-methyl-sensitive and –resistant Italian ryegrass to POST applications of several experimental and registered herbicides. The experimental herbicide combination AE F130060 03 was as effective as diclofop-methyl and more effective than chlorsulfuron plus metsulfuron, chlorsulfuron plus met...

Wheat (Triticum aestivum L. cv Etoile de Choisy) microsomes catalyzed the cytochrome P-450-dependent oxidation of the herbicide diclofop to three hydroxy-diclofop isomers. Hydroxylation was predominant at carbon 4, with migration of chlorine to carbon 5 (67%) and carbon 3 (25%). The 2,4-dichloro-5-hydroxy isomer was identified as a minor reaction product (8%). Substrate-specificity studies show...

Weed control failures due to herbicide resistance are an increasing and worldwide problem that significantly affect crop yields. Metabolism-based herbicide resistance (referred to as metabolic resistance) in weeds is not well characterized at the genetic level. An RNA-Seq transcriptome analysis was used to find candidate genes that conferred metabolic resistance to the herbicide diclofop in a d...

A wild population of a plant species, especially a cross-pollinated species, can display considerable genetic variation. Genetic variability is evident in differential susceptibility to an herbicide because the population can show continuous phenotypic variation. Recent, recurrent selection studies have revealed that phenotypic variation in response to low herbicide rates is heritable and can r...

Herbicide rate cutting is an example of poor use of agrochemicals that can have potential adverse implications due to rapid herbicide resistance evolution. Recent laboratory-level studies have revealed that herbicides at lower-than-recommended rates can result in rapid herbicide resistance evolution in rigid ryegrass populations. However, crop-field-level studies have until now been lacking. In...