CONTROL OF WHITE-PINE WEEVIL, PISSODES-STROBI, ON SITKA SPRUCE USING IMPLANTS CONTAINING SYSTEMIC INSECTICIDE

Young Sitka spruce, Picea sitchensis (Bong.) Carr., trees in three sta nds were treated with either Gelcaps(R) containing oxydemeton-methyl o r Acecaps(R) containing acephate to test their effectiveness in protec ting trees from white pine weevil, Pissodes strobi (Peck) attack. All treatments were applied in late March 1989. Weevil attack was recorded in early September 1989, 1990 and 1991. Attack was significantly redu ced (P < 0.01) in all but one stand/treatment combination in 1989. Gel caps provided significant protection (P < 0.01) in two of three stands after two years. Stem implants containing systemic insecticide can pr otect young Sitka spruce from weevil attack. Alternative delivery syst ems, such as the Ezect(R) lance, should be evaluated as they may impro ve the speed and lower the cost of operational treatments.