California Grapes: Managing Weeds in Drought Conditions

Drought conditions in grapes create unique challenges to weed control. Without rain there is little competition from annual weeds, so you may see more deep-rooted perennial weeds that are harder to control, especially field bindweed (Convolvulus arvensis).

Preemergence herbicides require approximately 1/4 to 1/2 inch of water within 3 weeks after application. If you decide to use a preemergence herbicide, you’ll need to wait for when rain is predicted or sprinkler irrigate.

If weeds are a problem now you can apply a contact herbicide. Postemergence systemic herbicides are effective too, but some weeds are resistant or tolerant; if you choose to use one, first learn about herbicide resistance.

Areas treated only with a postemergence herbicide may need light cultivation to remove weeds usually controlled with a preemergence herbicide.

For more information on preemergence and postemergence herbicides, weed susceptibility, and weed management visit the Grape Pest Management Guidelines.  View the grape year-round IPM program for more information on pest monitoring and management during winter.



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