Egg: Between 1 and 30 eggs are laid in the shoots
at any time during the host's warm, active growing season
Larva: Larvae tunnel into stems and form galls.
Multiple larvae are found in one gall. Overwintering occurs in
Pupa: Pupation occurs in the galls in the early
spring, and lasts 24 to 35 days at 64 to 68 degrees F.
Adult: Adults emerge in the late spring and early
Site of attack:
Impact on host:
Gall acts as a metabolic sink, reducing host's vigor,
making it less able to compete with favorable vegetation. Increased
vulnerablility to pathogens and other biocontrol insects. Stems
above the galls are retarded and may be unable to produce seed
Disturbed, high-density areas, close to moisture
(either high relative humidity or available surface water). Shade
preferred. Areas that are flooded, grazed, mowed or treated with
herbicide are not conducive to fly survival. Areas which experience
very cold winters and dry, hot summers are not conducive to species
Collect galls in the fall, winter or early spring.
Store in paper sacks or cardboard boxes at 39 to 46 degrees F.
Galls must remain moist during storage.
Control of Weeds in the West, N.E. Nees, et.al.
Harney County Weed Control
450 N Buena Vista Ave.
Burns, OR 97720
Phone: (541) 573-2506
Fax: (541) 573-8387