Avena herbicide control

Except direct use of allelopathic crops as cover crops, smother crops, and intercrops, applications of allelopathy for weed control include the use of allelopathic residues as an herbicide agent, e.g., pellets flours, water extracts, etc. The most common example of crop residue utilization is application of straw on the soil surface (mulching), e.g., rice straw inhibited germination of field bindweed (Convolvulus arvensis L.), winter wild oat (Avena ludoviciana Durieu), and little-seed canarygrass (Phalaris minor Retz.) (Lee et al. 1991 Tamak et al. 1994 Young et al. 1989). 

Benzoylprop-ethyl (31) and flamprop-isopropyl (32), two anilide herbicides selective in cereals with specific efficiency for the control of wild oat Avena spp.), have been developed in the research latoratories of the Shell Research Ltd. 

Difenzoquat methyl sulfate is a postemergence herbicide for the control of Avena spp. (A.fatua, A. ludoviciana, A. sterilis, A. barbata and A. macrocarpa) in wheat and barley, (Gruenholtze/a/.. 1974 Winfield, 1974 Blank and Behrens, 1974 Weis et al., 1974 Tafuro, 1974). Potatoes, sugar beet, beans, maize, lentils and several rye grasses are tolerant (Anonym, 1975). 

Difenzoquat methyl sulfate is specifically effective only against Avena spp., for the control of other grass weeds and broad-leaved weeds it must be used in combination with other herbicides. It can be used in tank mixture with the esters of the following herbicides 2,4-D, 2,4,5-T, MCPA, dichlorprop, bromoxynil, and ioxynil. 

Metabolism of the proherbicide (i.e., a non-phytotoxic chemical that requires metabolic conversion to yield an active herbicide) FE, is an example of how Phase 1 and II metabolism, and use of a safener imparts selectivity between crop and weed species (Figure 1). FE is used to control many graminaceous weed species such as Avena fatua, Echinochloa crus-galli, Digitaria ischaemum, and Setaria glauca (40) in wheat which is moderately tolerant to this proherbicide. The primary basis for the selectivity of FE in grasses is due to differences in metabolism (40-42). FE is rapidly hydrolyzed to the herbicide fenoxaprop (F) in wheat, and in all the previously mentioned graminaceous weeds (4J). In wheat. 

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