|Asian Longhorned Beetle|
The Asian longhorned beetle (ALH) (Coleoptera: Cerambycidae: Anoplophora glabripennis) attacks and kills healthy deciduous trees, and now has footholds in New York City and Chicago. The threat of this beetle to U. S. forests is considered the most critical issue for APHIS in the last 20 years; its escape from containment areas could be catastrophic. To date, detection of ALB infestations is based solely on visual surveys. An attractant lure to bait traps for the ALB is needed to more efficiently detect beetle infestations and to intercept future ALB introductions.
Gas chromatography-electroantennogram detector (GC-EAD) systems were constructed in ICEL and in the APHIS quarantine facility, Methods Development Center, Otis, MA. Logs infested with ALB from sites in New York City and Chicago, Illinois, were transported to the quarantine facility, and aeration extracts were prepared from ALB males and females separately. Two compounds not detected from females were consistently detected in samples from ALB males in May 1999, and antennae from both sexes of the beetle were found to be especially sensitive to these male-specific compounds by GC-EAD. Identification and synthesis was accomplished prior to the natural July emergence of ALB in China. The male-specific compounds are volatile dialkyl ethers (4-(n-heptyloxy)butanal and 4-(n-heptyloxy)butan-1-ol) of a type heretofore unknown from insects. In preliminary tests in the quarantine laboratory these compounds appeared to stimulate flight and walking in both sexes. However, July 1999 field tests in China failed to demonstrate attraction to the aldehyde and/or the alcohol, with or without a mixture of six host volatiles. Laboratory and field observations indicate that ALB males are territorial and that males recognize females upon antennal contact. In the summer of 2000, laboratory Y-tube bioassays demonstrated that walking male and female ALBs are significantly attracted to a 1:1 blend of 4-(n-heptyloxy)butanal and 4-(n-heptyloxy)butanol (10 [g each).