Environmental hazards of mobile ground spraying with cyanophos and fenthion for Quelea control in Senegal

Seven roosts of red-billed quelea, Quelea quelea, in the Senegal River Vall ey and Delta were visited during and after aerial or terrestrial treatments with either Cyanox (cyanophos 500 g a.i. liter(-1), five roosts) or Quelet ox (fenthion 640 g a.i. liter(-1), two roosts). The primary goal of the obs ervations was to provide data on environmental effects of cyanophos after m obile ground spraying operations. Twenty-six species of vertebrates (birds, reptile, fish) were found dead or debilitated near the spray sites. Effect s on nontarget fauna were most pronounced among owls (cyanophos and fenthio n) and blue-naped mousebirds, Uuocolius macrourus (fenthion). Among terrest rial invertebrates ants and carabid, and tenebrionid beetles were the most conspicuously affected. Among aquatic invertebrates affected tadpole shrimp s, Triops cancriformis, dominated. Extremely high residues were found immed iately after spraying on tree leaves in the spillway of a vehicle-mounted B erthoud Super Puma airblast sprayer (up to 1380 mg kg(-1)) and on birds fou nd dying under these trees (125-11,277 pg bird(-1), average 2720 pg bird(-1 )) in two roosts treated with cyanophos. Blue-naped mousebirds were identif ied as being particularly at risk. Side effects were not dose related. They were most severe after routinely practiced mobile ground spraying applicat ions which led to overdosing. These application methods impose severe envir onmental hazards, and should be abandoned, (C) 1999 Academic Press.