Effects of Certain Additives on Activity of Some Postemergence Herbicides in Relation with Carrier Volume

Abstract

Field experiments were conducted to determine the effect of OPPEE (octyl phenoxy poly ethoxyethanol), AAPE + SASA (alkyl aryl polyethoxylate + sodium salt of alkylsulfonate alkylate), thalestol, and TAE (tallow amine ethoxylate) at various concentrations to increase activity of glyphosate, glufosinate, and impzapyr or Imperata cylindrica L. and the effect of the same additive to increase activity of glyphosate on Cyperus rotundus L. and Cynodon plectostachyous (L.) Pers. Herbicides in combination with additives were applied at low carrier volume (14.4-48.7 1/ha) and at high carrier volume (138.2-265.0 1/ha). It was found that various additives alone did not increase activity of ghyphosate , glufosinate, and imazapyr on I. cylindrica and C. plectostachyous. But OPPEE at 0.12, 0.25 and 0.5% (v/v), thalestol at 0.25 and 0.5% (v/v), And TAE at 0.25, 0.5 and 1.0% (v/v) increased activity of glyphosate 0.63 kg ai/ha when it was applied at 14.4 l/ha on C. rotundus. OPPEE, AAPE + SASA, and thalestol at 0.25% (v/v), and TAE at 0.05% (v/v) also increased activity of glyphosate at 1.8 or 1.4 kg ai/ha on C. rotundus at the carrier volume of 38.1 and 128.2 l/ha. Phytotoxicity of glyphosate on I. cylindrica, C. rotundus , and C. plectostachyous increased when carrier volume was reduced. However, phytotoxicity of glufosinate and imazapyr on I. cylindrica decreased when carrier volume was reduced.