Studies of Monuron, Diuron, Simazine, and Atrazine on Weed Control, Grape Quality, and Injury to Vines

Abstract

Field trials were conducted to determine the effect of repeated applications of monuron, diuron, simazine, and atrazine on controlling weeds, grapevine injury and fruit quality in an established vineyard. All the materials gave good annual weed control, especially after several annual applications. Weed control was better with the ureas than with simazine during the first year of treatment. A high rate of monuron (25.6 pounds per acre per year applied in the vine row) was the only treatment that gave visible vine injury expressed as foliar chlorosis. Injury varied from none to severe with different varieties.

None of the treatments appeared to influence the quality of the fruit.

Some monuron had leached to the 6-12-inch soil depth, whereas none of the diuron was detectable below the top 6 inches, Leaves from plants receiving 25.6 pounds of diuron per acre per year (in the vine row on a 4-foot band) showed no reduction in photosynthetic activity.