TOMICUS PINIPERDA (COLEOPTERA, SCOLYTIDAE) REPRODUCTION AND BEHAVIOR ON SCOTCH PINE CHRISTMAS TREES TAKEN INDOORS

Tomicus piniperda, the pine shoot beetle, is an exotic insect that was first found in North America in 1992. A federal quarantine currently restricts movement of pine products, including Christmas trees, from i nfested to uninfested counties. We conducted a study to determine if T . piniperda would reproduce in Christmas trees that were cut and taken indoors during the Christmas season. Twelve Scotch pine, Pinus sylves tris, Christmas trees infested with overwintering T. piniperda beetles were cut in Indiana in early December 1993 and taken to Michigan. Fou r trees were dissected immediately, while the other 8 trees were taken indoors, placed in tree stands, and watered regularly. After 4 weeks indoors, 4 trees were dissected, and the other 4 were placed outdoors in Michigan for 7 weeks. Upon dissection, all overwintering sites occu rred along the lower trunk within the first 40 cm of the soil line; 81 % were found within 10 cm of the soil line. Adults collected from the 4 trees dissected in December produced viable progeny adults when plac ed on Scotch pine logs in the laboratory. Overwintering beetles became active and laid eggs in 4 of the 8 trees that had been taken indoors. All adults and progeny found in the 4 trees that had been placed outd oors for 7 weeks during cold January and February temperatures were de ad. Overall, T. piniperda can become active and breed in Christmas tre es that are cut and taken indoors in December. Tomicus piniperda survi val in trees that are discarded outdoors at the end of the Christmas s eason will depend largely on the prevailing temperatures.