WSU Extension

Hortsense

Common Insects & Mites : Pamphilid sawflies
(revision date: 4/30/2013)


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

Non-Chemical Management
  • Natural enemies usually suppress them.
  • Handpick and destroy larvae when possible.
Select non-chemical management options as your first choice!

Chemical Management

Pesticides are rarely necessary.

Images
    - hide images

+ Show larger images

 
Caption: Pine pamphilid sawfly larva
Photo by: A.L. Antonelli