How to Manage Pests

UC Pest Management Guidelines

Pear

Dormant to Delayed-Dormant Sampling

(Reviewed 11/12 , updated 11/12 )

In this Guideline:


During the dormant to delayed-dormant period, take a beating tray sample for pear psylla. Also take a shoot sample to examine fruit spurs (short shoots containing the flower buds) and terminal buds for mites, psylla, scale, and scab lesions. If mealybugs are a chronic problem in the orchard, look under the tree bark at the base of the main scaffolds.

Record your observations (example formPDF).

HOW TO SAMPLE

For orchards less than 20 acres, a smaller sample size may be taken than indicated below, but adjust the treatment thresholds to your sample size.

Beating Tray Samples

In December, monitor overwintering psylla adults with 100 beating tray samples per 20-acre block. Each sample is three taps.

Shoot and spur Samples

Once during the dormant season (December through early March), collect one shoot with a fruiting spur from the treetop and one from eye level from each of 50 trees in a 20-acre block, for a total of 100 spurs. (If you sample before February, pear psylla adults may be in the orchard but not their eggs. Also, pear rust mites become more evident in February when the buds begin to swell.)

Use a 14 to 20X hand lens to examine the fruiting spur for:

  • European red mite eggs
  • Pear psylla eggs
  • Pear rust mites
  • Pearleaf blister mites
  • Predatory mites

Examine the shoot for:

  • San Jose scales
  • Pear scab twig lesions

Count the number of spurs or shoots infested with these pests. Keep records of your results (example formPDF).

DECISION TABLE

Sample type Pest Management decision
Beating tray
Pear psylla
  • If an average of two or more adults per 20 beats, treat once according to the Pear Pest Management Guidelines.
. . . or . . .
  • If more than 50 adults per 50 beats, treat twice according to the Pear Pest Management Guidelines.

Resample following treatment to assess its effectiveness.

Shoot and spur sample
Pear psylla
  • If two or more dormant spurs have psylla eggs, treat according to the Pear Pest Management Guidelines.
European red mite
  • If a dormant treatment was properly applied and:
    • more than 10% of the spurs are infested, monitor throughout growing season.
    • less than 10% of the spurs are infested, then probably will not be a problem in coming year.
  • If no dormant treatment was applied and three or more spurs are infested in the sample of 100, monitor throughout growing season.
Pear rust mite
  • If two or more shoots are infested, treat according to the Pear Pest Management Guidelines.
Pearleaf blister mite
  • If any mites are present, treat according to the Pear Pest Management Guidelines.
San Jose scale
  • If a population of scale has developed in treetops, treat according to the Pear Pest Management Guidelines.
Pear scab lesions
  • Note areas of concern for future monitoring.
Bark sample
Mealybugs
  • If mealybugs are a chronic problem, examine under the bark of trees and note presence for future monitoring.

IMPORTANT LINKS

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Pear
UC ANR Publication 3455

General Information

L. G. Varela (Crop Team Leader), UC IPM Program, UC Cooperative Extension Sonoma County
R. B. Elkins, UC Cooperative Extension Lake County
R. A. Van Steenwyk, Insect Biology, UC Berkeley
C. Ingels, UC Cooperative Extension Sacramento County
L. R. Wunderlich, UC Cooperative Extension El Dorado County

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