Recommendations for control of cone and seed insect pests of black spruce,Picea mariana (Mill.) BSP, with insecticides

Foliar sprays of dimethoate (1.25 g Al per tree) and permethrin (0.028 g Al per tree), applied to run-off one week prior to female flower bud flush, s ignificantly reduced flower abortion, cone grazing, and shoot grazing cause d by spruce budworm, Choristoneura fumiferana (Clem.), larvae as well as da mage by the spruce cone maggot, Strobilomyia appalachensis (Michelsen). Tre atment with Bacillus thuringiensis var. kurstaki (B.t.) (0.012 B.U.I. per t ree) resulted in moderate protection from grazing damage to female flowers and cones as compared to treatment with dimethoate and permethrin. Systemic applications of acephate also reduced damage by spruce budworm larvae and the spruce cone maggot: fall and early spring applications were equal in ef ficacy, and the label rate (0.875 g acephate/3.2 cm dbh) provided similar p rotection to the half-label dose.