Plum

Year-Round IPM Program

(Reviewed 5/06, updated 5/06)

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 plums; information on additional pests is included in the Plum 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 to learn how to minimize water quality problems.

| Print annual IPM checklist (PDF) | Plum Pest Management Guidelines |
| Forms and photo ID pages |

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 during this period?
Survey weeds after first rains and complete a late-fall weed survey form (PDF).
If aphids are a chronic problem, treat in early November.
During pruning, look for dead wood caused by shothole borer and Pacific flathead borer. Prune and burn infested branches.
Knock off and destroy mummy fruit in cultivars susceptible to brown rot.
Take a 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 Plum Pest Management Guidelines.
Delay treatment for peach twig borer until bloom time.

Keep records of other pests you may see:

  • Fruittree leafroller egg masses
  • Italian pear scale
  • Peach twig borer hibernacula
  • American plum borer
  • 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 during this period?
On cultivars susceptible to brown rot, apply protective fungicide treatment as a delayed-bloom application.
Place omnivorous leafroller pheromone traps in the orchard at bloom.
Monitor San Jose scale:
Monitor peach twig borer larvae:
Monitor for leafrollers, other caterpillars, and katydids.
Monitor codling moth in orchards with a history of codling moth problems.
Look for spider mites and predatory mites weekly on first emerging basal leaves of scaffolds. Map areas of concern for future monitoring.
During long, cool bloom periods, monitor for western flower thrips.

Keep records of other pests you may see:

  • Ground squirrels
  • Pocket gophers
  • Voles
  • Bacterial canker
  • Armillaria root rot
  • Phytophthora root and crown rot

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 during this period?
Survey weeds in late spring and keep records on a late-spring weed survey form (PDF).
Monitor San Jose scale:
  • Continue checking pheromone traps.
  • Keep records on a degree-day monitoring form (PDF).
  • Treat if needed according to Plum Pest Management Guidelines.
Monitor omnivorous leafroller:
  • Continue checking pheromone traps.
  • Keep records on a degree-day monitoring form (PDF).
  • Treat if needed according to Plum Pest Management Guidelines.
Put up peach twig borer pheromone traps.
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 Plum Pest Management Guidelines.
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 Plum Pest Management Guidelines.
Continue monitoring codling moth if it has been a problem in the past.
Keep records of other pests you may see:
  • Caterpillars
  • Borers
  • Katydids
  • Diseases
  • Birds

Treat if needed according to Plum Pest Management Guidelines.

Harvest

Why is this period important in an IPM program?

Special issues of concern related to water quality: none.
What should you be doing during this period?
Take a fruit damage sample to assess the overall effectiveness of the current year's IPM program and to determine next year's needs.
Store picked fruit below 40° C to prevent storage rot or ripe fruit rot.

Postharvest (Fall)
What should you be doing during this period?
Consider zinc sulfate application to hasten leaf fall in order to disrupt aphid's life cycle.
Consider planting 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 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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