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Description and Biology

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Sycamore leaf beetles, Neochlamisus platani, are case bearing leaf beetles that feed on the leaves of sycamore. The adults are small, chunky, and wrinkled but very attractive bronzy beetles shaped somewhat like a caterpillar dropping. Females lay up to 150 eggs from mid May through June. They encase their orange eggs in fecal material on the under side of leaves (sometimes on top and sometimes on petioles). Orange grubs hatch about two weeks later and feed by chewing small holes all the way through leaves that appear as "shot holes" as the leaf expands. Grubs each construct a case from plant material and recycled plant material (frass) into which they can retreat to molt four times as they grow. The case also provides some protection from predators. When molested, grubs hold tightly to the leaf with their claws and mandibles. Grubs when mature, they wander to the leaf stipules and cling there where they resemble buds. They molt into pupae inside their cases, and from the pupal stages adult beetles emerge a few days later.

Sycamore leaf beetle

Sycamore leaf beetles are very small and only found on sycamore.

Another view of a sycamore leaf beetle.

Another view of a sycamore leaf beetle.

Sycamore leaf beetle grub

Sycamore leaf beetle grubs are usually hidden inside their cases.

The sycamore leaf beetle grub is completely hidden inside its ca

The sycamore leaf beetle grub is completely hidden inside its case.

Host Plants

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Sycamore leaf beetles feed only on American and London sycamores as larvae and adults.

Sycamore leaf beetles chew holes through leaves.

Sycamore leaf beetles chew holes through leaves.

Residential Recommendations

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Usually more than a third of sycamore leaf beetle eggs are parasitized by an exceedingly tiny wasp, Tetrastichus chlamytis. Should these beetles become abundant enough to warrant control measures, most of the insecticides sold for landscape use in the plant sections of big box stores and in nurseries and garden centers should give more than adequate control. As sycamores are often infested with sycamore lace bugs, treating for sycamore leaf beetles should help control the lace bugs as well.

Other Resources

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For assistance with a specific problem, contact your local Cooperative Extension Center.

This Factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology & Plant Pathology

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Publication date: March 6, 2019
Revised: Oct. 15, 2019

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