PROSPECTS FOR USING ODOR-BAITED TREES TO CONTROL TSETSE-FLIES (DIPTERA, GLOSSINIDAE)

Field studies in Zimbabwe elucidated the responses of Glossina morsita ns morsitans Westwood and G. pallidipes Austen to natural and artifici al trunks of trees baited with odours of acetone, 1-octen-3-ol and phe nols. The numbers of tsetse electrocuted in flight near the base of th e trunk increased 2-12 times when the trunk was shortened from 7.2 m t o 0.9 m and its diameter was increased from 25 an to 5 m, when the bas e was coloured blue or black to contrast with the upper trunk, or when the upper trunk was separated from the base by a gap of 2.7 m. A swar m flying near short trunks was more compact than near tall trunks. Ele ctrocuting grids to catch alighting tsetse indicated that only about 2 0% of the attracted tsetse alighted on the base of the trunk, whether this was blue or blue/black. Since there is presently no apparent mean s of cost-effectively avoiding the inhibitory effects of tall trunks, the use of odour-baited trees as baits for tsetse control seems unecon omical.