WSU Extension

Hortsense

Pear
 
Disease
Crown gall 
European canker (Nectria canker) 
Fire blight 
Pacific Coast pear rust 
Pear trellis rust 
Powdery mildew 
Pseudomonas blossom blast and dieback 
Scab 
Stony pit 
Virus diseases 
Insect
Aphids 
Apple-and-thorn skeletonizer 
Brown marmorated stink bug 
Codling moth 
Cutworms and armyworms 
Pear psylla 
Pear slug (pear sawfly) 
Pearleaf blister mite 
San Jose scale 
Spider mites 



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Caption: Apple-and-thorn skeletonizer
Photo by: A.L. Antonelli
  
Pear : Apple-and-thorn skeletonizer
(revision date: 5/7/2015)


Biology
The adult of the apple-and-thorn skeletonizer is a small dark-brown or reddish-brown moth. It overwinters as a pupa or an adult, with the females laying eggs in the spring. The caterpillars are yellow-green in color, have black spots and brown heads, and feed on the leaves of several plants including apple, crabapple, pear, cherry, and hawthorn. Caterpillars are about 1/2" long at maturity. Characteristic damage includes skeletonized leaves, or leaves that are rolled into a cone and tied with webbing. Damaged leaves are papery brown and drop prematurely.
Management Options

Non-Chemical Management
  • Hand-pick and destroy caterpillars when practical.
  • Pinch caterpillars inside rolled leaves or prune and destroy heavily infested twigs.
  • Naturally-occurring enemies help control populations of apple-and-thorn skeletonizers. Avoid use of broad-spectrum insecticides which kill beneficial insects.
Select non-chemical management options as your first choice!

Chemical Management

Bacillus thuringiensis (Bt) will provide control of young feeding caterpillars. Use a spreader-sticker with liquid Bt formulations. Homeowners should not make foliar applications to trees over 10 ft tall. Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Thuricide BT Conc
    Active ingredient: Bacillus thuringiensis subsp. kurstaki  |  EPA reg no: 4-226
  • Bull's-Eye Bioinsecticide
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-56872
  • ferti-lome Borer, Bagworm, Tent Caterpillar & Leafminer Spray
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-7401
  • Monterey Garden Insect Spray [Organic]
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-54705
  • This list may not include all products registered for this use.
Images

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Caption: Apple-and-thorn skeletonizer
Photo by: A.L. Antonelli