An improved synthetic attractant for the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae: Scolytinae), in northeastern California
The mountain pine beetle, Dendroctonus ponderosae Hopkins 1902, is found in pine forests throughout the western U.S., north to northern British Columbia and Alberta, Canada and south to Mexico. It causes high levels of pine mortality throughout its range. Hosts include many species of Pinus (Pinaceae); in northern California, D. ponderosae is a pest of pine types dominated by P. ponderosa Douglas ex Lawson et C. Lawson, P. contorta Douglas ex Loudon, P. monticola Douglas ex D. Don, and in mixed conifer types where P. lambertiana Douglas is the principal host (Struble 1945). The extensive geographic range of D. ponderosae, and the variability in environments in which it occurs, create challenges for developing effective semiochemical tools for reducing beetle-caused tree mortality. Nonrandom genetic variation occurs among populations of D. ponderosae and has been attributed to both geography and host differences (Stock & Amman 1980, Sturgeon & Mitton 1986, Langor & Spence 1991, Kelley et al. 2000, Mock et al. 2007). Variation has also been observed in D. ponderosae responses to host-produced pheromone synergists (Pitman & Vite´ 1969, Billings et al. 1976, Libbey et al. 1985, Miller & Lindgren 2000), leading to uncertainties in semiochemical deployment among locations and forest types.