Agriculture: Grape Pest Management Guidelines

Bloom to Véraison

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

About Bloom to Véraison

What should you be doing during this time?

Monitor for western flower thrips, particularly in vineyards near drying grains. Manage according to the Pest Management Guidelines.

Monitor leafhoppers, spider mites, and mealybugs weekly.

  • Keep records (example monitoring form PDF).
  • Manage if needed according to the Pest Management Guidelines.

Examine leaves and shoots for Botrytis bunch rot and powdery mildew. Manage if needed according to the Pest Management Guidelines.

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

Continue to check omnivorous leafroller pheromone traps weekly. Keep records (example monitoring form PDF).

Continue monitoring pheromone traps for vine mealybug.

  • If males are caught or honeydew, sooty mold, or ants are found, look for nymphs/females on surrounding vines.
  • Keep records (example monitoring form PDF).
  • If grape or vine mealybug nymphs/females are found on the vine, manage according to Pest Management Guidelines

Remove basal leaves and lateral shoots in the fruit zone beginning around berry set to minimize summer rot, Botrytis bunch rot, and leafhopper populations, and to maximize application coverage.

  • Time leaf pull before first-generation grape leafhoppers become adults.
  • Remove only the leaves on the shaded side of the canopy on non-divided trellis systems to prevent heat damage and sunburn of sensitive varieties (Thompson Seedless, Redglobe).

Treat for Botrytis before rain according to the Pest Management Guidelines.

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

  • Omnivorous leafroller
  • Grape leaffolder
  • Western grapeleaf skeletonizer

Keep records (example monitoring form PDF).

Monitor sticky traps for glassy-winged sharpshooters. Keep records (example monitoring form PDF).

Other pests or pest damage you may see:

Text Updated: 07/15