How to Manage Pests

UC Pest Management Guidelines

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Pear

Dormant/Delayed-Dormant Sampling

(Reviewed 3/08, updated 3/08)

In this Guideline:

How to sample
Decision table
Important links
Publication
Glossary

During the dormant/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 form—107 KB, PDF).

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/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

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 form—107 KB, PDF).

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 PMGs. . . . or . . . If more than 50 adults per 50 beats, treat twice according to PMGs. Resample following treatment to assess its effectiveness.
shoot/spur sample	pear psylla	If two or more dormant spurs have psylla eggs, treat according to PMG.
	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 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 spurs are infested, treat according to PMG.
	pearleaf blister mite	If any mites are present, treat according to PMG.
	San Jose scale	If a population of scale has developed in treetops, treat according to PMG.
	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

Pest monitoring form (107 KB, PDF)
Photos of pests monitored during dormancy/delayed dormancy

PUBLICATION

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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