1. UC IPM
  2. Agriculture
  3. Pear
  4. Postharvest Survey
Agriculture: Pear Pest Management Guidelines

Postharvest Survey

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Monitor for pests during the postharvest season. Check fruit left on trees to assess the effectiveness of your codling moth program. Also, take a shoot sample to determine management needs for psylla, mites, and pear scab. Note whether pearslug is present in the orchard.

Record your results (example form PDF).

How to Sample

Fruit Sampling

Collect 300 fruit left on trees after harvest. Examine for stings or deep entries to evaluate the effectiveness of the codling moth program.

Shoot Sampling

Collect one top shoot from 20 trees per 20-acre block. Using a 10 to 14X hand lens, look at 5 leaves on each shoot (for a total of 100 leaves) for the presence of

  • European red mite: Count the number of European red mites.
  • Pear psylla eggs and nymphs: Count the number of infested shoots.
  • Pear scab
  • Pearleaf blister mite: Count the number of shoots with blistered leaves.
  • Twospotted and other webspinning spider mites: Count the number of mites.
  • Pear rust mite: Count the number of infested shoots.
  • Pearslug: Note location of infestation.
  • Predatory mites

Decision Table

Sample type Pest Management decision

Fruit sample

 Codling moth
  • If 1 to 2% of the fruit (3 to 6 fruit) are infested, reevaluate your IPM program for the following year and be prepared to treat at first egg hatch of the overwintering generation, according to the Pear Pest Management Guidelines.

Shoot sample

 Pear psylla
(nymphs and eggs)
  • If 5 or more top shoots are infested, treat according to the Pear Pest Management Guidelines.
European red mite
  • If 50 to 200 mites per 100 leaves, treat according to the Pear Pest Management Guidelines.
  • Use lower thresholds if predators are absent.
Pear scab
  • If lesions are found, be prepared to treat in early spring.
Webspinning spider mites For Bartlett and Bosc varieties (Asian and other varieties usually have higher thresholds):
  • In early districts only, treat postharvest with oil if more than 50 mites per 100 leaves are present.
  • If both pest and predaceous mites are present in ratio of 10:1, treatment may not be needed.
Pear rust mite
  • If 2 or more shoots are infested, treat according to the Pear Pest Management Guidelines.
Pearleaf blister mite
  • When 3 or more shoots show damage, plan to treat in the fall according to the Pear Pest Management Guidelines.
Pearslug
  • Note localized infestations for future monitoring.

Important Links

Text Updated: 11/12
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