Of the various methods for the eradication of G. palpalis that have been tried in Kenya, hand-catching has the most limited application.
Total and discriminative bush-clearings of the river banks have been used on a considerable scale and progress on the Yala, Magori, and Nyando rivers is reviewed. The decrease in fly-populations caused by these clearings is gradual, but complete eradication may be achieved. Maintenance of the clearings is however difficult, the initial cost varied from £200 to £300 per mile and labour was often difficult to obtain in sufficient numbers.
The use of 5 per cent. DDT sprays on the fringing vegetation along 20 miles of the Mbogo river gave dramatic results and G. palpalis was eradicated at a cost of £42 per mile. The rate of application was 15 to 20 lbs. of DDT per acre and the residual effect lasted for at least 14 days during dry weather, but was rapidly lost during the rains.
Spraying along the Ainamotua gave equally promising results.
Areas under treatment, either by hand-catching, bush-clearing or spraying with DDT, must be properly isolated from other tsetse-infested areas if quick results are to be achieved.