Field Bindweed(Convolvulus arvensis)Control in Corn(Zea mays)and Sorghum(Sorghum bicolor)with Dicamba and 2,4-D

Abstract

Control of field bindweed(Convolvulus arvensisL.) on irrigated land was studied by application of herbicides once in the fall and then only in the spring for the next 4 yr. Control of field bindweed 8 months after a fall application of 2.2 kg/ha of dicamba (3,6-dichloro-o-anisic acid) or 3.4 kg/ha of 2,4-D [(2,4-dichlorophenoxy)acetic acid] was 90 and 83%, respectively. Spring applications of 0.28 kg/ha of dicamba, 0.56 kg of 2,4-D, or the mixture of these two herbicides suppressed the growth of field bindweed similarly each year. By the fall of the fourth year, field bindweed covered an average of 9% of the soil surface in the plots that received both fall- and spring-applied herbicide treatments, 72% in plots that received only fall-applied herbicide treatments, and 80% in the untreated plots. Yield of corn(Zea maysL. ‘Pioneer 3306’) was significantly higher in all treated plots than in the untreated check plots in 1 out of 2 yr. Yield of sorghum [Sorghum bicolor(L.) Moench ‘Pioneer 833’] was not increased significantly in any treated plots, but in 1 yr the mixture of 0.28 kg/ha of dicamba plus 0.56 kg/ha of 2,4-D reduced yield significantly when this mixture was applied twice at these same rates in the spring.