Long-Term Field Bindweed (Convolvulus arvensis) Control in Two Cropping Systems

Abstract

Three herbicides, amine salt of 2,4-D [(2,4-dichlorophenoxy)acetic acid], glyphosate [N-(phosphonomethyl)glycine], and dicamba (3,6-dichloro-o-anisic acid) were applied for field bindweed (Convolvulus arvensisL.) control in grain/summerfallow or grain/legume rotations. After the first year all herbicide retreatments were made using 2,4-D amine. The 2,4-D treatment at 3.4 kg/ha gave 65% field bindweed control. Field bindweed control averaged 17% higher when the 2,4-D was applied in August rather than July. The 3.4-kg/ha rate gave 45% better field bindweed control than the 1.1 kg/ha rate. Dicamba at 6.7 kg/ha gave 90% field bindweed control and glyphosate at 4.5 kg/ha gave 86% control. Dicamba persisted in the soil for 1 to 3 yr after application and caused winter wheat (Triticum aestivumL.) and lentil (Lens culinarisMedik.) yield loss. Crop yields were highest more than 90% of the time from plots treated with 2,4-D or glyphosate.