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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:


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 form107 KB, PDF)

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
  • 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.
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.
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

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