Effects of Remedial Application of Lindane on Emergence of Natural Enemies of the Western Pine Beetle, Dendroctonus brevicomis (Coleoptera: Scolytidae) 1

Abstract

Field tests of remedial applications of registered 2% lindane sprays to ponderosa pine, Pinus ponderosa Laws, bark infested with the western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Scolytidae), indicated that the overall emergence of predaceous natural enemies is reduced by 89%, and a ratio of natural enemy to western pine beetle emergence is diminished by 80%. Species showing significant effects due to lindane treatment include Enoclerus lecontei (Wolc.), Aulonium longum LeConte, and Medetera aldrichii Wheeler. Differential in situ mortality of predators and prey indicates a need for further study of dispersal stage mortality of predators and prey as well as the contribution of natural enemies to long-term population regulation before continuing registration of lindane for remedial control of the western pine beetle.