Leaf Skeletonizers on Oaks

Leaf skeletonizers are pale yellow-green caterpillars that create veiny skeletons as they feed on upper leaf surfaces (Figure 1). There are several leaf skeletonizer species that feed on different tree species, but their activity is rarely noticed. Usually, weather or natural enemies hold populations in check. Oak skeletonizers caused extensive feeding damage in some areas in south central Kentucky in 2015. Andy Mills, Meade County Extension agent for Agriculture reported feeding damage on shingle oak late last week. Feeding by the first of two generations should be nearly over, but a second generation occurs during July and August.

Figure 1. Skeletonized leaves of shingle oak (Photo: Andy Mills, UK)

Figure 2. Individual feeding sites of oak leaf skeletonizer with silk pads and black frass pellets. (Photo: Lee Townsend, UK)

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Management

Control of these insects may be warranted on small, newly established landscape trees, but several consecutive defoliations would be necessary to affect the health of larger, established trees. General tree and shrub insecticides that list caterpillars on the label can be used if control is necessary and practical. Support tree health by watering if needed, pruning when warranted, and fertilizing as recommended.

 

By Lee Townsend, Extension Entomologist

 

 

Posted in Landscape Trees & Shrubs