Robert R. Borys

MCH Released in a Novel Pheromone Dispenser Prevents Spruce Beetle, Dendroctonus rufipennis (Coleoptera: Scolytidae), Attacks in South-central Alaska

Field tests of 3-methyl-2-cyclohexen-1-one (MCH), the antiaggregation pheromone of the spruce beetle, Dendroctonus rufipennis Kirby, were conducted in south-central Alaska in stands of Lutz spruce, Picea x lutzii Little, and Sitka spruce, P. sitchensis (Bong.) Carr. The deployment of MCH in a novel releaser significantly reduced trap catches and spruce beetle attacks on standing live spruce by 96 and 87%, respectively. The results of this study demonstrate the first successful field test of MCH in Alaska for the prevention of spruce beetle attacks on standing, live spruce.

Evaluation of Systemic Insecticides for Control of Elatobium abietinum (Homoptera: Aphididae) on Picea sitchensis in Southeast Alaska

Spruce aphid, Elatobium abietinum (Walker) (Homoptera: Aphididae), causes chlorosis, defoliation and mortality of spruce, Picea spp., but has also been recorded infesting pine, Pinus spp., and Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Furniss and Carolin 1977, U.S. Dept. of Agric. For. Serv. Misc. Pub[. 1339). This species, an exotic invasive in North America, was first reported in British Columbia in 1916 presumably originating from native populations in Europe (Carter and Halldórsson 1998, Scot. For. Comm. Tech. Pap. 24) and has since spread throughout coastal areas of the Pacific Northwest where maritime climates moderate temperatures and increase E. abietinum survivability (Bejer-Petersen 1962, Oikos 13: 155-168). Little has been published on E. abietinum in North America. Sitka spruce, Picea sitchensis (Bong.) Carr., is a preferred host and grows in a narrow band along the Pacific coast from a latitude of about 61°N in south-central Alaska to 39°N in northern California. Extensive amounts of P. sitchensis mortality has been attributed to E. abietinum infestations in British Columbia (Koot 1991, Can. For. Serv. For. Pest Leafl. 16), but appears to be a rare occurrence elsewhere. Since 1998, large-scale outbreaks have occurred in Southeast Alaska resulting in defoliation of P. sitchensis over extensive areas (Wittwer 2003, U.S. Dept. of Agric. For. Serv. Tech. Rept. R10-TP-113) and some tree mortality. Elatobium abietinum overwinters as wingless, parthenogenetic females, which allows populations to rapidly increase following mild winters. There are usually several generations per year. Feeding is restricted to 1-yr-old and older needles as settling on younger needles is deterred by volatiles present in the epicuticular wax (Jackson and Dixon 1996, Ecol. Entomol. 21: 358-364). Needles that are fed upon quickly turn