Agriculture: Walnut Pest Management Guidelines

Budbreak Through Bloom

This year-round IPM program covers the major pests of walnut in California.

About Budbreak Through Bloom

What should you be doing during this time?

If conditions favor walnut blight, manage according to the Pest Management Guidelines.

Place codling moth pheromone traps in mid-March to determine first moth emergence.

  • Check traps twice weekly until biofix, and weekly thereafter.
  • Use degree-days for monitoring pest development.
  • Keep records (example degree-day monitoring form PDF).

If using mating disruptants for codling moth, place them in orchards using female biofix according to the Pest Management Guidelines.

Look for dead and Botryosphaeria and Phomopsis infected branches. Flag trees for pruning in summer or after rainfall ceases.

Consider using the Leaf Wetness Model (LWM) to time fungicide sprays if rainfall is greater than 0.25 inch and temperatures are greater than 50°F.

Look for crown gall and manage if needed according to the Pest Management Guidelines.

Keep records of other pests you may see:

  • Phytophthora
  • Armillaria (oak root fungus)
  • Gophers
  • Ground Squirrels
  • Tree Squirrels
Text Updated: 07/17