Tolerance of several wild oat herbicides by a range of winter wheat varieties

Abstract

SUMMARY Screening tests exposed varietal differences in the tolerance of winter wheat to high doses of the wild oat herbicides difenzoquat and diclofop‐methyl. Subsequent yield trials at recommended and higher doses confirmed the sensitivity of Score and Sportsman to difenzoquat and showed Atou, Bouquet and Hobbit to be less tolerant than some other varieties. In most varieties, earlier spraying proved safer than treatment at or beyond the beginning of jointing. Varietal differences with diclofop‐methyl were smaller and inconsistent. Crops damage from these two herbicides was more severe in another experiment the following season, in which isoproturon at double the recommended dose also caused severe damage but flamprop‐methyl was fairly well tolerated by all varieties.