Trifluralin for Green Foxtail Control in Barley and Flax

Abstract

Field experiments were conducted to study the feasibility of using α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) for selective control of green foxtail(Setaria viridis(L.) Beauv.) in barley(Hordeum vulgareL.) and flax(Linum usitatissimumL.), and to determine the effect of crop competition on the phytotoxicity of trifluralin to green foxtail. Barley tolerated rates of trifluralin up to 2.24 kg/ha, the maximum rate used, without injury or reduction in grain yield when the herbicide was applied and incorporated to a shallow depth 1 day after seeding. Flax seeded in trifluralin-treated soil 5 or 10 days after application of the herbicide suffered a stand reduction from rates of 1.12 kg/ha or more; however, no significant reduction occurred in the seed yield. Trifluralin provided excellent control of green foxtail in both crops. Barley was a strong competitor against green foxtail while flax had poor competitive ability. Crop competition had a complementary effect on the degree of green foxtail control obtained with trifluralin.