Herbicide-Variety Studies of Young Grapevines

The response of young grapes to herbicides varied greatly from one location to another. Differences in soil and management influenced this response, as did grape variety. The same twenty varieties were evaluated at two different locations. Ten additional varieties were included at a third location. Three herbicides (simazine, trifluralin, and DCPA) were common to all three tests. Trifluralin was the least phytotoxic to the most varieties of young grape vines. Simazine gave the best control but produced considerable phytotoxicity symptoms on many varieties. DCPA produced very little stunting but gave little weed control. In addition, bensulide and diphenamid were evaluated at one location on 10 varieties. DP 733, a new numbered herbicide, was evaluated at two locations. Since shallow incorporated trifluralin will control weeds at ½ to 1 lb/A, trifluralin will prove useful for weed control in grape nurseries. Studies are being made of grass herbicides such as trifluralin, DCPA, diphenamid, and bensulide combined with simazine or other new herbicides for broadleaf weed control.