The dogwood sawfly.

Sawflies belong to the Hymenoptera, the same group that ants, bees, and wasps belong to. They are very unusual though in that their larvae look more like caterpillars than the larvae of other insects from the same order. In fact, many people mistakenly identify the larvae as being caterpillars of butterflies and moths, the Lepidoptera.

The easiest way to tell a sawfly larva from a caterpillar is to look at the number of prolegs at the back end. Caterpillars usually have five pairs of these false legs while sawfly larvae have six to eight pairs. The adults are completely different from most Lepidoptera because they do indeed appear to be wasp-like. The difference here is that sawflies do not possess a stinger of any kind.

Most insect larvae that eat leaves are fairly particular on the genera or even species of plant they consume. Dogwood sawflies will eat the leaves of any species of dogwood, the variety does not seem to matter. They represent a pest to nurseries and gardens sporting the plant. The damage they inflict on a tree will depend on their numbers and the time of year it is inspected. Early on, little damage is visible, especially if the number of larvae is small. Large populations, what may be considered an infestation, can strip a tree completely as summer gives way to fall.

The larvae will burrow into soft wood or perhaps the soil (click here for reference) to overwinter. Once secure, they molt for the last time to become pupae. They have also been known to find shelter in the wood siding of houses. The overwintering pupae are targets for woodpeckers searching for a meal and have indirectly caused damage because of the activity of these birds. In the spring adults emerge from the pupae, mate, and lay eggs on nearby dogwood trees starting the cycle all over again.

Thanks for reading.     Ericspix     Eric Svendsen