NC State Extension Publications

Description and Biology

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Dogwood sawflies, Macremphytus tarsatus, are slender, shiny black, wasp-like insects. Dogwood sawflies emerge from May to July. Females insert up to 100 eggs in a leaf using a “saw-like” ovipositor. Each egg causes a small bump that eventually turns brown. Immature dogwood sawflies are caterpillars that change colors, textures, and appearances several times during their development. The second larval stage is covered in a white waxy covering and the last larval instar is yellow and black. Young caterpillars skeletonize leaves. Older caterpillars eat everything but the midrib. They eventually become pale cream color with black spots and grow to about an inch long at which time they are yellow and black. Mature caterpillars bore into decaying or soft wood and form cells in logs, landscape timbers, and even lawn furniture. We have one generation per year in North Carolina.

The sawfly is very similar to the dogwood sawfly.

The sawfly is very similar to the dogwood sawfly.

A sawfly very similar to the dogwood sawfly.

A sawfly very similar to the dogwood sawfly.

Dogwood sawflies lay their eggs in rows next to leaf veins.

Dogwood sawflies lay their eggs in rows next to leaf veins.

Dogwood sawflies insert their eggs

Dogwood sawflies insert their eggs into dogwood leaves.

Early dogwood sawfly caterpillars

Early dogwood sawfly caterpillars are fluffy and white.

Older dogwood sawfly caterpillars a

Older dogwood sawfly caterpillars are white or cream with small, black spots.

Mature dogwood sawfly caterpillar

Mature dogwood sawfly caterpillars are yellow and black.

Host Plants

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Various species of dogwoods seem to be the only hosts for the dogwood sawfly.

Residential Recommendations

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The dogwood sawfly may cause considerable defoliation because they feed in groups. Small caterpillars can be dislodged by shaking and then trampled under foot. If chemical control is warranted because of excessive defoliation, insecticidal soaps and horticultural oils are effective as long as the dogwood sawfly caterpillars are less than an inch long. Older caterpillars are very tough! Most of the insecticides labeled for residential landscape use also provide adequate control.

References

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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 and Plant Pathology

Publication date: March 18, 2017
Revised: Sept. 16, 2019

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