Weed control in dwarf cogongrass (Imperata cylindrica (L.) Beauv. var. koenigii (Retz.) Durand et Schinz) fields by herbicides

Abstract

To better understand which herbicides were best suited for controlling weeds in Dwarf cogongrass (Imperata cylindrica (L.) Beauv. ‘Hajime’) field, their safeties to Dwarf Cogongrass and herbicidal activities against a variety of weeds were investigated using pot and field test. The results of pot test in a greenhouse showed that of 18 herbicides tested, six could be used with Dwarf cogongrass; three were effective pre-emergence herbicides (S-metolachlor, pyroxasulfone, triaziflam) and three were effective post-emergence herbicides (harosulfuron-methyl, atrazine, triclopyr). The findings obtained from field test showed that the two sequential applications, S-metolachlor/harosulfuron-methyl and S-metolachlor/atrazine, are effective for control weeds without damaging Dwarf cogongrass when S-metolachlor was applied as a pre-emergence herbicide at a rate of 300 g a.i./10 a, followed by harosulfuron-methyl as a post-emergence herbicide at a rate of 100 g a.i./10 a and/or atrazine as a post-emergence herbicide at a rate of 300 g a.i./10 a.