Field Bindweed Control with Cultivation, Cropping, and Chemicals

Various combinations of crops, herbicides, and tillage were evaluated for field bindweed ( Convolvulus arvensis L.) control in western South Dakota. Four crop rotations (continuous wheat ( Triticum aestivum L.), wheat-fallow, wheat-sorghum ( Sorghum vulgare Pers.), and wheat-sorghum-fallow) were modified by the application of (2,4-dichlorophenoxy)acetic acid (2,4-D) and/or the use of post-harvest tillage. Intensive cultivation and 2,4-D treatment were used to aid in the control of field bindweed in forage crops grown on a long-term basis and in conjunction with small grain rotations. Treatment with 2,4-D in a grain crop and with non-selective herbicides after harvest were tested. Crops were planted the succeeding 2 or 3 years and observed for effect of chemical residue. The established plants could be essentially eliminated while utilizing adapted crop rotations. The use of 2,4-D alone or in combination with cultivation made it possible to reduce the stand of field bindweed (20.7 to 22.2 shoots/sq yd) 90% or more in 3 years in all rotations. A ¾-lb/A rate of 2,4-D in June prevented seed production, killed susceptible plants, and weakened the remaining plants, but a follow-up treatment of 2,4-D in the fall, post-harvest cultivation, or post-harvest treatment with herbicides such as 2,3,6-trichlorobenzoic acid (2,3,6-TBA), 3,6-dichloro- o -anisic acid (dicamba), or 4-amino-3,5,6-trichloropicolinic acid (picloram) was necessary to kill them.