Eastern spruce gall adelgid
July 30, 2015
Norway spruce is the most common host for this adelgid. Females overwinter near buds and lay eggs at bud bases when buds begin to break. Galls produce stunted and deformed shoots. Galls turn red and open from around mid-August to October, at which time adults emerge and reproduce.
Horticultural oils can be used to treat the overwintering stage when trees are dormant. Insecticides are more effective in mid-April to early May before the candles open. Cut off and destroy galls before they open. A soil application of insecticide may also work well in fall. Contact your local extension agent for current recommendations. Avoid planting Colorado spruce and Douglas-fir together to reduce the severity of Cooley spruce gall.
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