Prune

Year-Round IPM Program

(Reviewed 6/06, updated 6/06)

These practices are recommended for a monitoring-based IPM program that reduces water quality problems related to pesticide use. Links take you to information on how to monitor, forms to use, and management practices. Track your progress through the year with the annual checklist form. This program covers the major pests of prunes; information on additional pests is included in the Prune Pest Management Guideline.

Water quality becomes impaired when pesticides move off-site and into water. Each time a pesticide application is considered, review the Pesticide Application Checklist at the bottom of this page for information on how to minimize water quality problems.

Dormancy/Delayed-dormancy (leaf fall to bud swell)

Why is this season important in an IPM program?

Special issues of concern related to water quality: dormant sprays, drift, and rain runoff.

What should you be doing at this time?
If aphids are a chronic problem, treat during the period from November 1 to the end of December.
Take a dormant spur sample for San Jose scale, mites, and aphids (if not treated in November).
  • Keep records on a monitoring form (PDF).
  • Treat if needed according to Prune Pest Management Guideline.
Delay treatment for peach twig borer until bloom time.
During pruning, look for dead wood caused by shothole borer and Pacific flatheaded borer. Prune and burn infested branches.
Knock off and destroy mummy fruit to reduce brown rot problems.
Allow resident vegetation to grow; monitor weeds in October and November.

Keep records of other pests you may see:

  • Euriophyid mites
  • Fruittree leafroller egg masses
  • Italian pear scale 
  • Peach twig borer hibernacula
  • Tree borers
  • Voles
  • Pocket gophers

Bloom (green tip to petal fall)

Why is this season important in an IPM program?

Special issues of concern related to water quality: drift.

What should you be doing at this time?
Treat orchards where brown rot is a chronic problem; monitor weather to determine the need for additional treatments.
Monitor San Jose scale:
Monitor peach twig borer larvae:
  • Time bloom treatments according to Prune Pest Management Guideline.
  • In fresh market, or if no dormant or bloom spray was applied, put up and monitor pheromone traps (by March 20 in San Joaquin Valley; April 1 in Sacramento Valley).
  • Keep records on a degree-day monitoring form (PDF).
Monitor for leafrollers and other caterpillars. Treat if needed according to Prune Pest Management Guideline.
Mow ground cover.

Keep records of other pests you may see:

Fruit development (petal fall to harvest)

Why is this period important in an IPM program?

Special issues of concern related to water quality: runoff from irrigation, and drift.

What should you be doing at this time?
Survey weeds in late spring.
Monitor San Jose scale:
  • Continue checking pheromone traps.
  • Keep records on a degree-day monitoring form (PDF).
  • Treat if needed according to Prune Pest Management Guideline.
Monitor obliquebanded leafroller:
Monitor peach twig borer if crop is fresh market and no dormant or bloom spray was applied:
Monitor aphids from petal fall until July 15, or until a treatment is applied.
  • Keep records on a monitoring form (PDF).
  • Treat if needed according to Prune Pest Management Guideline.
Monitor webspinning spider mites weekly using a 5-minute search, starting June 1.
  • Keep records on a monitoring form (PDF).
  • Treat if needed according to Prune Pest Management Guideline.
Monitor rust and treat if needed according to Prune Pest Management Guideline.
Monitor cytospora canker.
  • Remove (cut out) cankers.
  • Destroy dead or damaged wood.
Take a fruit damage sample just before harvest. Record the results on a monitoring form (PDF) to assess the effectiveness of current year's IPM program.
Keep records of other pests you may see. Treat if needed according to Prune Pest Management Guideline.

Postharvest (Fall)

Why is this period important in an IPM program?

Fall is when aphids migrate back into the orchard.

What should you be doing at this time?
Sample for mealy plum aphid and leaf curl plum aphid at 75% leaf fall to determine need for dormant sprays.
Consider zinc sulfate application to hasten leaf fall in order to disrupt aphid's life cycle.
Survey weeds after first rains and complete a late-fall weed survey form (PDF).
  • Let resident vegetation grow between rows.
  • Manage weeds in rows with pre- or postemergent herbicides or nonchemically in organic orchards.
Consider planting a cover crop.
Plan for next year.

Pesticide application checklist

When planning for possible pesticide applications in an IPM program, consult the Pest Management Guidelines, and review and complete this checklist to consider practices that minimize environmental and efficacy problems.

For more about mitigating the effects of pesticides, see the Mitigation page

PDF: To display a PDF document, you may need to use a PDF reader.

Top of page


Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2019 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   /PMG/C606/m606yi01.html revised: May 21, 2019. Contact webmaster.