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Survey Weeds—Early Season

For wine and raisin grapes, survey vineyards in late spring or early summer. For table grapes in the San Joaquin Valley, survey in March; in the Coachella Valley, survey in January or February. Surveying can help determine the spectrum of weeds present. These surveys help in making decisions about herbicide choice or cultivation equipment and practices.

Grapevines are most sensitive to weed or cover crop competition during the first few years of growth. As grapevines become established, competition from weeds is reduced because of the vine canopy shade. Weeds between the vine rows can be mowed or cultivated.

When using herbicides, record your weed observations (sample weed survey form—92 KB, PDF), and choose pre- and postemergent herbicides. Keep records to track weed populations from year to year to better understand ongoing weed control problems, such as resistance.

How to survey your fields:

• Survey your vineyard after summer annuals have germinated.
• Pay particular attention to perennials. Check for regrowth of perennials a few weeks after cultivation.
• Pay particular attention to wet spots, as these may be problem areas for weed growth.
• Survey areas around the vineyard, as these areas could be a potential source for wind-disseminated seeds, such as marestail and fleabane.
• Sketch a diagram of the orchard and mark areas where perennials are found.
• Rate infestation either using a numeric scale from 1 to 5 (1 being the lightest), or use “light,” “medium,” or “heavy.”
• Keep records of your survey results. By knowing which species are present, you will be able to make appropriate decisions about cultural and chemical controls.

Information collected over a period of years tells you how weed populations may be changing and how effective your management operations have been.

Important links

• Photos of summer annual weeds you may see
• Photos of perennial weeds you may see
• Early-season weed survey form (92 KB, PDF)
• Integrated weed management

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