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How to Manage Pests
UC Pest Management Guidelines
Pear
Sampling During Fruit Development
(Reviewed 3/8,
updated 3/8)
In this Guideline:
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During the fruit development season examine fruit and
leaves for the presence of, or damage
caused by, pear psylla, mites, mealybugs, caterpillars, aphids, sawfly (pear
slug), thrips, and plant bugs.
Keep
records of your observations (example form—
HOW TO SAMPLE
Take
weekly samples of shoots that contain a fruit cluster, one from the treetop and
one at eye level, from each of 20 trees in a 20-acre block. Examine both leaves
and fruit for pests.
Leaves.
Use a 10 to 14X hand lens to examine 5 leaves
per shoot (total of 200 leaves) for:
- Pear psylla (nymphs, eggs,
and honeydew)
- Mites:
- European red mite (on both
top and eye-level shoots)
- Twospotted and other
webspinning spider mites (early season, primarily on eye-level shoots;
later in season top and eye-level shoots)
- Other pests:
- Aphids (russeting and
honeydew)
- Pear slug (eggs and larvae)
- Pearleaf blister mite
(damage)
- Katydids (feeding damage and
nymphs)
Fruit. Examine
fruit for evidence of pests or damage:
- Codling moth (stings and
larval entries)
- Obliquebanded leafroller
(look where fruit touch)
- Pear rust mite (russeting at
calyx and stem ends)
- Boxelder bugs (mostly in
areas near riparian corridors)
- Lygus bugs
- Stink bugs (also do a
30-minute search for adults)
DECISION TABLE
| Sample type |
Pest |
Management decision |
| leaves |
pear
psylla |
If one or more shoots have psylla eggs or nymphs, treat according to PMG. |
| European
red mite
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- If 10 or fewer European red mites or
eggs are found per 100 inspected leaves, don't treat.
- If 11 to 50 are found, treat with oil according to PMG.
- If more than 50 are found, add a miticide with the oil according to
PMG.
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| webspinning
(e.g. twospotted) spider mites |
For Bartlett and Bosc varieties (thresholds for Asian
pears and other varieties are generally higher):
- If 1 to 50 mites per 100 leaves sampled,
treat with oil according to PMG.
- If more than 50 mites per 100 leaves sampled, add miticide to oil
according to PMG.
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| aphids |
In cool springs, evaluate damage according to PMG. |
| pear
slug |
Spot treatments according to PMG may be warranted for localized infestations. |
| pearleaf
blister mites |
If present, plan to treat for this pest according to PMG. |
| katydids |
Treatment may be necessary if foliage damage and nymphs are present on tree. |
| fruit clusters |
codling moth |
If any eggs or larval entries are found, treat according to PMG. |
| obliquebanded leafroller |
If more than two clusters out of 40 contain leafrollers, treat according to PMG. |
| pear rust mite |
If two or more pears have rust mites or if any pear has more than 30 mites, treat according to PMG. |
| Plant
Bugs: |
| consperse
stink bug |
If
more than three fruit per 30 minute search show evidence of stink bug, treat
according to PMG. |
| western boxelder bug |
If bugs or damage are present, a spot treatment according to PMG may be warranted. |
| lygus
bug |
One
damaged pear in 100 is cause for concern and calls for further sampling and evaluation of control need. |
IMPORTANT LINKS
![[UC Peer Reviewed]](/IMAGES/logo-ucpeerreviewed.jpg)
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 Co.
R. B. Elkins, UC Cooperative Extension Lake Co.
R. A. Van Steenwyk, Insect Biology, UC Berkeley
C. Ingels, UC Cooperative Extension Sacramento Co.
L. R. Wunderlich, UC Cooperative Extension El Dorado Co.
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