Agriculture: Grape Pest Management Guidelines

Dormancy

This year-round program section covers the major pests of wine and raisin grapes grown in California. For table grapes, see the TABLE GRAPE YEAR-ROUND IPM PROGRAM.

About Dormancy

What should you be doing during this time?

Carry out preventative practices for trunk diseases:

  • Use delayed pruning or double pruning in February or later.
  • Use applications of pruning-wound protectants after pruning and before rain in November through January.

In coastal areas, set out orange tortrix pheromone traps by December.

  • Check traps twice weekly until a biofix date is established; thereafter, check traps weekly.
  • Keep records (example monitoring form PDF).

If present, treat for Phomopsis cane and leaf spot before rainfall.

Sample for nematodes in January or February.

Carry out dormant-season sanitation activities.

  • Destroy prunings of older infested wood to reduce pest sources.
  • Remove dried grape clusters on vines and disc weeds and clusters where orange tortrix or omnivorous leafroller is a problem.
  • In vineyards with a history of branch and twig borers, examine old pruning scars and dead parts of vines for brown frass and wood dust.
  • If you have vine mealybug, steam sanitize equipment before moving to an uninfested area of the vineyard.

Survey weeds to plan a weed management strategy. If herbicides are used.

  • Use the late-winter survey form (PDF) to record your observations and make pre- and postemergence herbicide selection decisions.
  • Remove leaves and debris under the vine before applying herbicides.
  • Do not make preemergence herbicide applications if heavy rains are expected soon after application. However, applications should be made when a rain event of 0.25-0.50 inches is expected within 2-3 weeks.
  • If possible, make preemergence herbicide application after dormant activities, such as pruning, are completed to reduce soil movement.
Text Updated: 07/15