How far can tsetse travel?

Tsetse can fly at about 20 km/h (Gibson et al., 1991) and they are active for something like 30 minutes each day (Bursell & Taylor, 1980). So they could travel up to 10 km every day! However, they tend to make many short flights every day and these are not all in the same direction. Hence, in practice, savannah species such as G. m. morsitans and G. pallidipes move about one kilometre a day and a fly front can advance about 25 kilometres in a year (Hargrove, 2000). This movement means that areas cleared of tsetse rapidly become re-invaded from adjacent infested areas. Indeed, in experiments carried out in Zimbabwe in the 1980s, virtually every fly in a 4 square kilometre block was killed by aerial spraying in one night (Vale et al., 1984). Within a day, the catches in the block were back to normal because flies had swarmed back into the block from neighbouring areas.

Controlling tsetse over small areas is like trying to make a hole in a lake with a cup!