HOUSEHOLD AND STRUCTURAL INSECTS Attraction of Subterranean Termites (Isoptera) to Carbon Dioxide

Subterranean termites, Reticulitermes spp., were attracted to carbon dioxide (CO2) in laboratory and Þeld tests. In behavioral bioassays, Reticulitermes flavipes (Kollar), Reticulitermes tibialisBanks, andReticulitermes virginicusBankswere attracted toCO2 concentrations between5 and 50 mmol/mol. In further bioassays, R. tibialis and R. virginicus were attracted to the headspace from polyisocyanurate construction foam that contained 10Ð12 mmol/mol CO2. In soil bioassays in the laboratory, more termites foraged in chambers containing CO2-generating formulations than in unbaited control chambers. In Þeld tests, stations containing CO2-generating baits attractedR. tibialis away from wooden fence posts at rangeland sites in Colorado. For all of the CO2 formulations tested, termites foraged in signiÞcantly more bait stations at treatment fenceposts than in bait stations at the control fenceposts. By the end of the 8-wk study, the number of bait stations located by termites at treatment fenceposts ranged from 40 to 90%. At control fenceposts, termites foraged in only a single station and the one positive stationwas not located by termites until week 5 of the study. At treatment fenceposts, termites foraged equally in active stations (containing a CO2-generating bait) and passive stations (with no CO2-generating bait), indicating that bait stations may beneÞt passively from a proximal CO2 source in the soil. CO2 used as an attractant in current baiting systems could improve their effectiveness by allowing earlier exposure of termites to an insecticide.