Response of some scolytids and their predators to ethanol and 4-allylanisole in pine forests of central Oregon

Lindgren multiple funnel traps were set up in pine Forests of central Orego n to determine the response or scolytid bark beetles to ethanol and 4-allyl anisole (4AA). Traps were baited with two release rates of ethanol (4.5 or 41.4 mg/hr) and three release rates of 4AA (0, 0.6, or 4.3 mg/hr) in a 2 x 3 factorial design. All traps also released a 1:1 mixture of alpha- and bet a -pinene at 1 1.4 mg/hr. Of 13,396 scolytids, Dendroctonus valens made up 60%, Hylurgops spp. 18.5% Ips spp. 16%, Hylastes spp. 1.8%, Ganthotrichus r etusus 0.9%, and bark beetle predators another 2.8%. Increasing the release rate of ethanol in the absence of 4AA increased the number of most scolyti d species caught by 1.5-3.7 times, confirming its role as an attractant. Ip s Latidens, Temnochila chlorodia and clerid predators were exceptions and d id nor show a response to higher ethanol release rates. Release of 4AA at t he lowest rare inhibited attraction of most scolytids, with a significant r eduction in G. retusus, Hylastes macer, and Hylurgops porosus when compared to traps without 4AA. A high release rate of 4AA further inhibited respons es for most beetles compared to low 4AA. Seven species were significantly d eterred by high 4AA, including the latter three, and Hylastes longicollis, Hylastes nigrinus, Hylurgops reticulatus, and Ips latidens. Exceptions incl ude Hylurgops subcostulatus, which was significantly attracted to both low and high 4AA, and I. pini, which was attracted to low and high 4AA in combi nation with low ethanol, but unaffected by either release of 4AA with high ethanol. Dendroctonus valens was significantly attracted to low 4AA and una ffected by high 4AA. Predators appeared to be less inhibited by 4AA than mo st bark beetles. Although 4AA can deter the attraction of some secondary ba rk beetles to ethanol in combination with alpha- and beta -pinene, this inh ibition could be weakened for certain species by increasing ethanol release rates. 4-Allylanisole may have some utility for managing the behavior of s econdary bark beetles sensitive to this compound.