THE EXPERIMENTAL APPLICATION OF INSECTICIDES FROM A HELICOPTER FOR THE CONTROL OF RIVERINE POPULATIONS OF GLOSSINA-TACHINOIDES IN WEST-AFRICA .8. THE EFFECTS OF 2 SPRAY APPLICATIONS OF OMS-570 (ENDOSULFAN) AND OF OMS-1998 (DECAMETHRIN) ON GLOSSINA-TACHINOIDES AND NON-TARGET ORGANISMS IN UPPER-VOLTAN

The results of discriminative spraying of endosulfan and decamethrin from a Bell 47G-4A helicopter to fringing riverine forest habitats of G. tachinoides in the Komoe Valley, Upper Volta, are described. The insecticides, diluted with diesel oil, were applied from the helicopter through a unilateral (left-side) arrangement of 4 rotary atomizers. Three experimental blocks were each sprayed twice at an interval of .apprx. 1 mo., 1 with endosulfan at individual swath dosages of 100 g (a.i.)[active ingredient]/ha, the 2nd with endosulfan at 200 g (a.i.)/ha and the 3rd with decamethrin at 12.5 g (a.i.)/ha. In spite of aerially applied dieldrin barriers, there was extensive reinvasion by G. tachinoides during the inter-spray period; consequently conclusions were largely drawn from the data collected before and after the 2nd cycle of insecticide applications. The reinvasion problem is discussed. Endosulfan at 200 g/ha was the most effective in controlling G. tachinoides. Even though the track of the helicopter was about 15 m from the banks of the River Komoe, contamination with insecticide was sufficient to adversely affect some aquatic nontarget organisms. Decamethrin caused high mortalities of 2 aquatic prawns, Caridina africana and Macrobrachium raridens. One yr later fish and C. africana populations recovered, but not M. raridens.