Common Insects and Mites: Pamphilid sawflies

Biology

Sawflies are primitive wasps that do not sting. There are several families including pamphilids. Most of them are herbivores and while some feed on deciduous trees, most of the species in Washington feed on conifers. The larvae are caterpillar-like and can be rather large, up to an inch or more in length. They are webspinners and when finally noticed, one sees a sizeable “nest” of webbing, frass (small chunks of excrement), and chewed dead needles in the tree canopy. Larval feeding on needles can cause localized defoliation, but they are rarely a significant problem.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Natural enemies usually suppress them.
• Handpick and destroy larvae when possible.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

Pesticides are rarely necessary.