Sawflies on Douglas fir - Balsam fir sawfly
Neodiprion sp. is a sawfly found on Douglas fir and listed in references such as Western Forest Insects. But some entomologists call the sawfly found locally on Douglas fir by the name, balsam fir sawfly (Neodiprion abietis complex). The complex apparently has 5 strains separated by geography and host: 4 in the Eastern US (2 on balsam fir, 1 each on white and black spruce) and 1 in the West. The host list for the Western strain includes: Pacific silver fir, subalpine fir, Engelmann spruce, Sitka spruce, and Douglas-fir. As most sawfly identification is based on adult specimens, only a successfully-reared adult will confirm the true identity of these particular sawflies.
In 2005, there was an outbreak of sawfly damage to Douglas fir in several counties in the Willamette Valley. Sawflies can defoliate plants if occurring in large numbers. Damage from this pest is usually localized and may not require control or spot applications only. There are many natural controls (weather, parasites, diseases) that usually keep these populations in check. Images of the sawfly and damage can be found below right side of page.
Web links:
Balsam fir sawfly, Nova Scotia Natural Resources
2005 Forest Health Highlights in Oregon - cover shot shows damage.
Original version: <25 May 2010)
Last update <20 February 2017>
Author: R.L. Rosetta, Extension Nursery Integrated Pest Management, Department of Horticulture, Oregon State University/NWREC.
Close up of Neodiprion scutellatus feeding on Douglas fir.
Neodiprion scutellatus
Close up of Neodiprion scutellatus feeding damage on Douglas fir.
Neodiprion scutellatus feeding damage on Douglas fir.