How to Manage Pests
UC Pest Management Guidelines
Pear
Postharvest Survey
(Reviewed
11/12
, updated
11/12
)
In this Guideline:
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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 ).
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
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European red mite: Count the number of European
red mites.
-
Pear psylla eggs and nymphs: Count the number of
infested shoots.
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Pear scab
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Pearleaf blister mite: Count the number of
shoots with blistered leaves.
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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.
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| Webspinning spider mites
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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.
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| 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.
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IMPORTANT LINKS
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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