Phytotoxicity of seven graminicides on maize

Abstract

Phytotoxicity of single and double dosages of metolachlor, dimethenamid, acetochlor A and B, alachlor, flufenacet and a mixture of atrazine-sulcotrione, were evaluated on maize (Zea mays L.) in a greenhouse, using soil with a clay content of less than 10%. Chlorosis, necrosis, stunting, scorched leaves and malformation of plant parts, was apparent throughout the trial period. The mean germination time of seedlings was less than seven days with all treatments and thus commercially acceptable although some treatments differed significantly from the control. Prior to 15 days after herbicide application some of the treatments resulted in whiplashing of the growth point and decreased plant dry mass, which could be interpreted as either on the borderline of commercial acceptability or commercially unacceptable. However, all symptoms of phytotoxicity were outgrown 30 days after herbicide application. It appeared that single and double dosages of acetochlor B and atrazine-sulcotrione as well as the double dosage of alachlor should be used with care on soil with less than 10% clay. The remaining treatments appeared to be safe on the same soil.