CHEMICAL ATTRACTANTS FOR TRAPPING YELLOWJACKETS VESPULA-GERMANICA ANDVESPULA-PENSYLVANICA (HYMENOPTERA, VESPIDAE)

Worker yellowjackets (Hymenoptera: Vespidae) were captured in traps ba ited with combinations of an aqueous solution of acetic acid and polye thylene caps loaded with either butyl butyrate, heptyl butyrate, or is obutanol. Vespula germanica (F.) were captured in large numbers in tra ps baited with acetic acid and isobutanol or acetic acid and butyl but yrate. Vespula pansylvanica (Saussure) were captured in large numbers in traps baited with heptyl butyrate, acetic acid and heptyl butyrate, acetic acid and butyl butyrate, and acetic acid and isobutanol. Aceti c acid generally enhanced the attractiveness of these other compounds to V. pensylvanica and V. germanica. Vespula atropilosa (Sladen) were captured in large numbers in traps baited with heptyl butyrate or acet ic acid and heptyl butyrate, with no apparent effect of the addition o f acetic acid to the trap, and they were only weakly attracted to othe r baits. The importance of acetic acid to attraction of V. garmanica a nd V. pensylvanica to these lures supports the hypothesis that this re sponse is food-finding behavior. The chemical lure comprised of acetic acid and isobutanol can be used for trapping the worldwide pest V. ge rmanica, with the added advantage of simultaneous attractiveness to V, pensylvanica.