Agriculture: Grape Pest Management Guidelines

Bloom to Véraison

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 Bloom to Véraison

What should you be doing during this time?

Monitor leafhoppers and spider mites weekly. Keep records (example monitoring form PDF). Treat if needed according to the Pest Management Guidelines.

Monitor for Botrytis and powdery mildew by inspecting leaves and shoots.

If European fruit lecanium scale has been a problem in the past, monitor for egg hatch to time treatment.

Check pheromone traps for:

  • Omnivorous leafroller
  • Orange tortrix (in coastal areas)

Keep records (example monitoring form PDF).

In areas other than southern San Joaquin valley, put up vine mealybug pheromone traps. In all areas, check traps every two weeks.

  • If males are caught or honeydew, sooty mold, or ants are found, look for sessile nymph/female infestations on surrounding vines.
  • Keep records (example monitoring form PDF).
  • Treat if needed according to the Pest Management Guidelines.

Monitor Pseudococcus mealybugs by looking for honeydew, sooty mold, and ant activity.

  • Keep records (example monitoring form PDF).
  • If you see crawlers, treat if needed according to the Pest Management Guidelines.

To reduce possible summer rot, Botrytis, and leafhoppers, remove basal leaves or basal lateral shoots beginning around berry set.

  • Time leaf pull before first-generation grape leafhoppers become adults.
  • Treat for Botrytis prior to rain, if leaves are not removed.

Monitor caterpillars if they have been a problem in the past:

  • Omnivorous leafroller
  • Orange tortrix
  • Grape leaffolder
  • Western grapeleaf skeletonizer

Keep records (example monitoring form PDF).

Monitor for sharpshooters:

  • Glassy-winged sharpshooter

In coastal regions near riparian and landscape areas check for:

  • Blue-green sharpshooter

Change sticky traps weekly. Keep records (example monitoring form PDF).

Extra care must be taken when applying systemic herbicides, such as glyphosate near or after veraison.

Other pests or pest damage you may see.

  • Grasshopper
  • Whitefly
Text Updated: 07/15