Roseslug

There are several sawfly species that feed on roses. The common roseslug, Endelomyia aethiops, can be found skeletonizing rose leaves in late spring and early summer. This species, along with the bristly roseslug, Cladius difformis, belong to the family Tenthredinidae. The larvae look similar to caterpillars but are actually more closely related to bees and wasps. The common roseslug is pale green with a light tan head capsule. The bristly roseslug has many hairlike bristles. Along with three pairs of true legs, they have three pairs of abdominal legs which lack the hooked crochets on the prolegs of true caterpillars. The adult sawflies are small, thick-waisted wasps, mostly black in color.

Roseslug feeding creates a distinctive windowpanelike damage. First feeding damage is usually found in May or June in the PNW.

Cultural control includes hand picking and disposing of infested leaves. There are a range of chemical control options including biorationals such as insecticidal soaps and horticultural oils. Direct contact is necessary. Although they look like caterpillars, they are not affected by Bt sprays as are the larvae of moths and butterflies.

Links:

Sacramento Rose Society: Rose sawflies. There are great images and information on the different types of rose sawflies found in Northern California and Oregon.

University of Minnesota: Defoliators/leaf feeders - Three species of rose sawflies.

UC Irvine, Bristly roseslug, Cladius difformis. Wonderful images of bristly roseslug sawflies, particularly adults at this website.

Images of the adult roseslug can be found at the Biodiversity Database of Washington DC website.

Roseslug larva under rose leaf

Photo: Rosetta

Early roseslug feeding damage

Photo: Rosetta

Leaf skeletonizing damage caused by roseslug feeding

Photo: Rosetta

Roseslug pupa

Photo: Ken Gray

Bristly roseslug larva

Photo: Ken Gray

Bristly roseslug cocoon

Photo: Ken Gray

Bristly roseslug adult
Photo: Ken Gray

Page last modified 6/3/09