Repellency and Toxicity of Conophthorus ponderosae Hopkins (Coleoptera: Scolytidae) by the Host Monoterpene Myrcene

Abstract

Abstract Seed orchards produce high-quality seed from selected tree genotypes. In the intermountain west, Conophthorus ponderosae Hopkins (Coleoptera: Scolytidae) is a pest in seed orchards of ponderosa pine, Pinus ponderosa (Laws). The effect of myrcene as a deterrent to coneattack by C. ponderosae in a ponderosa pine seed orchard was examined. Two factors were considered, timing of cone cluster attack and average brood production per cone cluster. There was a delayed attack by C. ponderosae on cones treated with vials of myrcene attached at thebase of cone clusters. During both 2003 and 2004, final brood production per cone was not affected significantly by the presence of myrcene. During 2003, brood production was influenced by the timing of attack, with later attacks resulting in fewer brood adults per cone cluster. The toxicity of myrcene to adult C. ponderosae was examined in a laboratory and compared with that of (+)-α-pinene, another host-produced monoterpene that acts as a synergist for the male attractant pheromone pityol.