Factors favouring the choice of flamprop‐methyl, methyl (±)‐2‐N‐(3‐chloro‐4‐fluorophenyl)benzamido propionate for the control ofavenaspecies in wheat

摘要

AbstractThe post‐emergence herbicide, methyl (±)‐2‐N‐(3‐chloro‐4‐fluorophenyl)benzamido‐propionate, flamprop‐methyl, showed good activity against oat with selectivity in wheat. It was superior in performance to flamprop‐isopropyl and benzoylprop‐ethyl already being marketed for wild oat control. It gave even more effective control of seed set in the oat than did the other compounds, prevented tiller growth and as a result of its higher activity was less dependent on crop competition. Selectivity of flamprop‐methyl, however, was similar to that previously reported for related compounds, i.e. it was dependent on its rate of degradation and the subsequent detoxication of the biologically active acid to inactive conjugates. The rate of degradation of flamprop‐methyl is comparable to that of benzoylprop‐ethyl but the more active acid produced accounts for the improved performance of the former. The corresponding ethyl ester showed the highest rate of degradation and although generally comparable in performance to the methyl ester there was a tendency for the inhibition on the oat to last for a shorter period. Performance of flamprop‐methyl is influenced by environmental factors such as temperature or water stress. These factors had an effect during the first 2 weeks after compound application, reducing the translocation of the active metabolite to its site of action and having a small but detectable effect