Agriculture: Walnut Pest Management Guidelines


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

About Postharvest

What should you be doing during this time?

Look for dead and infected branches from Botryosphaeria and Phomopsis cankers. Only prune to reduce inoculum if there is a dry period predicted. Otherwise prune during summer.

Manage orchard floor vegetation.

  • Assess weeds and keep records (example weed survey formPDF).
  • Plant cover crops after harvest to reduce water runoff and improve nitrogen management. Select an appropriate late planting mix that will succeed after harvest.
  • Apply preemergence herbicides in-row before fall weeds emerge and include a post-emergence herbicide if weeds have started to emerge. Consider blowing or sweeping leaf debris immediately before applying preemergence herbicides to facilitate herbicide contact with soil.

Remove huller waste materials to reduce navel orangeworm overwintering sites.

Text Updated: 07/17