May. The young nymphs attach themselves to the base of the needles and form a gall. About the first week in August, these galls break open and the mature nymphs crawl to the needles. They molt and transform to sexual winged females that lay eggs on the needles for the overwintering generation. Thus, there are two generations each season. The most effective control method consists of spraying early in April to control overwintering adults, using a horticultural oil or insecticidal soap, which are among the compounds registered for use against this pest in Connecticut.
Horticultural oil removes the bloom from blue and white spruces.
An insecticidal soap spray or chlorpyrifos applied soon after the new growth begins in May will give good control of the young before galls are formed. Imidacloprid may be effective as a soil-applied systemic treatment. Consult the labels for dosage rates and safety precautions. Spruce needle miner, Endothenia albolineana . The caterpillars of this moth mine the needles, along with several other species.