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

Before a pesticide application is made and when planning for possible applications in an IPM program, review and complete this checklist to minimize water quality and other problems.
  • Follow each practice in the year-round IPM Program.
  • Identify target pest, treatment threshold, trigger, or justification for treatment.
  • Consider nonchemical alternatives.
  • Identify important natural enemies that might be impacted by pesticide application.
  • Choose a pesticide from the UC IPM Pest Management Guidelines for the target pest, considering impact on natural enemies and honey bees and consulting the UC IPM Watertox Database for water quality concerns. Select an alternative chemical or nonchemical treatment when risk is high.
  • Consider chemical class if pesticide resistance is an issue.
  • Identify sensitive areas (for example, waterways or riparian areas) surrounding your application site.
  • Identify practices or mitigation measures to be used to reduce pesticide movement off site.
  • Choose sprayers and application methods that minimize off-site movement.
  • Review and follow pesticide handling, storage, and disposal guidelines.
  • After an application is made, record application date, product used, rate, and location of application.
  • Follow up to confirm that treatment was effective.

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Statewide IPM Program, Agriculture and Natural Resources, University of California
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