Selective and conventional house-spraying of DDT and bendiocarb against Anopheles pseudopunctipennis in southern Mexico

Indoor feeding behaviors and mortalities of Anopheles pseudopunctipennis fe males were evaluated following contact with selective (bands covering mosqu itoes' preferred resting areas) and full applications of DDT and bendiocarb on indoor sprayable surfaces. The DDT residues provoked strong avoidance b ehavior. To a lesser degree, mosquitoes were also repelled by bendiocarb-sp rayed surfaces. Because of strong irritancy/repellency, unfed mosquitoes we re driven outdoors in proportionally higher numbers. The resting time on se lectively or fully DDT-sprayed huts was greatly reduced in comparison to be ndiocarb-sprayed huts. Although unfed mosquitoes tended to rest on non-DDT- sprayed surfaces in the selectively treated hut, the man-biting rate was si milar with both types of treatments. Unfed mosquitoes were repelled less fr om selectively bendiocarb-treated surfaces. Similar reductions in postfed r esting times were observed on all surfaces suggesting that once fed, mosqui toes rested on sprayed surfaces for shorter intervals of time. Engorged mos quitoes had normal resting behavior (pre- and postspray) within the range o f preferred resting heights in both DDT- and bendiocarb-sprayed huts, but t he proportion of mosquitoes fed in the DDT-treated huts was lower. Selectiv e spraying of walls was as effective as spraying the complete walls with bo th insecticides, but DDT was more effective in reducing mosquito-human cont act. These studies show that by more effectively targeting vector behavior, a cost-effective alternative to traditional control techniques can be achi eved.