Tree Fruit Research & Extension Center

Cullage Assessment & Education

Quick Identification Guide to Apple Postharvest Defects & Disorders Cards

Arthropod Damage

The Arthropod section of the card set includes all the major insect damage found in Washington apples. This section also includes some mite damage. At a later date more cards may be developed for this section which would include other forms of animal damage, such as, bird pecks and rodent feeding, as well as, any emerging or reclassified disorders. Click on the tab below for the pest damage you are interested in viewing. For ordering information visit the Order Information section of Introduction. The cards shown on this site are slightly modified to accomodate web formatting. Figures may appear fragmented in some browsers. Please report viewing problems here. Any reproduction of the card images or content without permission is in violation of WSU Copyright policies.



ARTHROPODS: Scale, Thrips & Other   

Apple maggot external Apple maggot internal

There are several other insects that may only occasionally cause fruit damage. However, if present, they could cause quarantine problems at some export destinations.

San Jose scale

Figures 1&2: Areas with apple maggot are subject to strict quarantine regulations. External dimpling from egg laying and internal feeding are pictured here.

Figure 3: Severe San Jose scale present with darker pigment rings around the feeding sites. Scale may be found only in the stem bowl or calyx if infestation is light, or may cover the fruit with heavy infestations.

thrips pansy spot late

Figure 4: Blister mite is not common in apples. Feeding causes surface scarring after the mites are gone. Other mite feeding may cause russet similar to powdery mildew damage.

Figure 5&6: “Pansy spots” from thrips egg laying appears early as bleached tissue around a small dimple. Later it may have a dark border around a greenish depression. There may be one or more spots per fruit. There is no internal damage. Discovery of thrips could cause export lot rejection at some destinations.

blister mite
thrips pansy spot early





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