Indoor low-volume insecticide spray for the control of Anopheles albimanus in southern Mexico. Village-scale trials of bendiocarb, deltamethrin and cyfluthrin.

A comparative insecticide village-scale trial was carried out to determine the efficacy of low-volume (LV) indoor spray of bendiocarb, deltamethrin and cyfluthrin for the control of Anopheles albimanus in a coastal plain of southern Mexico. Low-volume spray was conducted with knapsack mist-blowers, giving an average discharge rate of 215 ml/min, which deposited droplets of 50-100 microns. Using this technique, 25 houses were treated/sprayman/day as compared with 8 houses/sprayman/day using conventional hand compression pumps. Indicators of LV mortality showed a residual activity of 10 wk as compared with 13 wk of activity for wettable powder (WP) (bendiocarb). When comparing expenditures, LV spray costs were 43% less when using bendiocarb, 83% less with deltamethrin and 74% less with cyfluthrin with respect to the conventional WP spray of the same insecticides. Low-volume spray time was reduced by one-third, with respect to WP. Malaria incidence was reduced by 53 and 56%, respectively, in the bendiocarb LV and deltamethrin LV treated villages as compared with the untreated village.