CONTROL OF PERSIAN DARNEL (LOLIUM-PERSICUM) AND OTHER GRASSES WITH CLETHODIM

The response of Persian darnel, green foxtail, wild oat, and volunteer cereals to clethodim applied at two growth stages, and the effect of these treatments on flax yield and quality were determined in a series of field experiments in which each weed species was evaluated separat ely. Clethodim applied at 45 g/ha provided excellent control of Persia n darnel, green foxtail, wild oat, and volunteer wheat and barley. Set hoxydim applied at 150 g/ha provided excellent control of Persian darn el, green foxtail, wild oat, and volunteer barley. Flax was tolerant a t five times the recommended rate of application and was unaffected by plant growth stage at time of application. When applied at-an early ( 2- to 3-leaf) stage, control of Persian darnel, green foxtail, wild oa t, and volunteer wheat and barley was excellent at 20 g/ha. Except for Persian darnel, weed control as determined by reduction in plant dry weight, was negatively affected by growth stage at time of-application . Although visible control and reduction in plant dry weight were some what less when clethodim was applied at the 4-to 5-leaf stage, control of each weed species was acceptable. When weight of water in plant ti ssue (fresh weight - dry weight) was used as a measure of living plant tissue, wild oat and volunteer barley control were unaffected by grow th stage at time of application.