Johnsongrass Control in Corn with Soil Incorporated Herbicides

Abstract

Johnsongrass [Sorghum halepense(L.) Pers.] control in corn (Zea maysL.) was studied from 1970 to 1972 using consecutive annual applications of alachlor (2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide) at 3.4 kg/ha, butylate (S-ethyi diisobutylthiocarbamate) at 4.5, 9.0, and 13.4 kg/ha, and EPTC (S-ethyl dipropylthiocarbamate) at 3.4, 6.7, and 13.4 kg/ha. In 1970, control was less than 60% for all herbicides, and there was no significant rate response. In 1971 butylate and EPTC at all rates provided 79 to 93% control. Alachlor gave 49% control. In 1972 control was similar to 1971. Control with one cultivation was additive to these herbicidal effects. Seed treatment with 0.5% 1,8-naphthalic anhydride adequately protected the corn from herbicide injury. Corn yields were closely correlated with johnsongrass control.