2,4-hexadienyl butyrate and related compounds highly attractive to yellow jackets (Vespula spp.).

When 147 synthetic organic compounds were field-tested as attractants for yellow jackets ( Vespula spp.), 47 caught one or more specimens. The results obtained with these 47 compounds and with a few others structurally related are presented. Most tests were conducted in the Willamette Valley, Oregon, in 1964 and 1965. A majority of the compounds were tested by placing about 0.25 g in the bottom of glass jars equipped with inverted screen cones having a hole at the apex. Insects responding to lures entered the holes and were unable to escape from the traps. Although a variety of rather potent attractants was discovered, the single most effective class of compounds was that of the 2,4-hexadienyl esters; 6 of the 9 most active materials fell in this category. The single most effective compound was 2,4-hexadienyl butyrate. Of the 3 species of yellow jackets attracted to the lures, V. pensylvanica (Saussure) was by far the most abundant. The attractants appeared to be highly specific for yellow jackets since few other insects and no beneficial species such as honey bees were caught.