Contarinia pseudotsugae, C. constricta, C. cuniculator
(Photo courtesy of Oregon Department of Agriculture.)
Douglas-fir needle midge larva in needle. (Photo by Tracey Olsen, Pennsylvania Dept. Agriculture.)
Adults are small orange flies 2 mm (1/16") long.
Yellow-brown to orange-colored eggs, each with a red spot, can be seen with a 16× hand lens on new needles and buds.
Legless larvae are 2 mm (1/16") long with white, yellow, orange, or olive-green bodies, and no distinct head.
Contarinia pseudotsugae, C. constricta, and C. cuniculator are all very similar in appearance and behavior. Biology and life cycle
Adults typically emerge in April to May and lay eggs on buds and new growth. Larvae emerge after a few days and burrow into needles, forming galls, where they spend the summer.
In fall, larvae emerge from galls, drop to the ground, and enter the soil.
In spring, larvae pupate in soil before adult emergence.
Individual adults live only a few days; however, emergence occurs over several weeks.
Needles infested with Douglas-fir needle midge larvae. (Photo by Tracey Olsen, Pennsylvania Dept. Agriculture.)
Only affects Douglas-fir Growing years
Monitor for adult Douglas-fir needle midge emergence to effectively time spray applications. (See
Overview of Trapping and Monitoring Options.) Use the
USPEST.ORG online phenology and degree-day model for Douglas-fir needle midge to predict adult emergence. Place 5 traps per field or 10 per acre; check frequently to time sprays, if needed.
Record locations of needle damage found in late summer to scout and place traps accordingly the following spring.
Note: Traps will collect insects other than needle midges, including non-pest species of midges.
Douglas-fir needle midge is in larval stage feeding inside the needles.
Feeding damage includes yellowish swellings (galls), yellowing needles, and premature needle drop.
Some trading partners, such as Mexico, have zero tolerance for selected species of Douglas-fir needle midges.
Douglas-fir needle midge trap. (Photo by Chal Landgren, OSU.)
Remove and destroy heavily infested trees in the early fall, before larvae exit needles.
Time insecticide application based on collection of adults in emergence traps, field scouting, or the
USPEST.ORG online phenology and degree-day model for Douglas-fir needle midge. Make first insecticide application based on collections in traps, scouting, weather, and bud development.
Note: Insecticides are effective only against adults. (Visit the
PNW Insect Management Handbook.) At harvest
Exclude trees with signs of Douglas-fir needle midge damage when shipping internationally.
C. constricta is the only species on the Mexican quarantine list; however, try not to ship any damaged trees, since misidentification is likely and Douglas-fir needle midges have caused the most load rejections by Mexico. (See Pest Quarantine Information.) Note: Shaking is not 100% effective, and infested needles may remain on trees.
Look for eggs: April through May
Look for larvae in soil: January through February
Look for larvae in needles: June through September
Look for larvae in soil: October through December
Look for pupae: March through April
Look for adults: April through May
Swollen and yellow needles present: June through December
Place emergence traps: mid-March through mid-May
Apply spray control measures based on monitoring: mid-April through mid-June
Remove infested trees: August through mid-October
Keep visibly infested trees from international shipments: mid-October through mid-November