Adults of Anopheles maculatus were tested for their residual activity to wettable
powders (WP) and water dispersible granule (WG) formulations of deltamethrin. The residual
ef fect ivenes s and l i fespan of del tamethr in WG and WP were al so as ses sed agains t the
mosquitoes using rough and smooth surfaces of bamboo. Tests were conducted once a month
up to 14 months after spraying using WHO standard method for the bioassay of insecticidal
deposits on wall surfaces. Mortality data revealed that both deltamethrin WG and WP were
effective against An. maculatus up to 14 months post-spraying. Efficacy and residual activity
of deltamethrin WG at 25mg/m2 had proved to be the longest on both rough and smooth
surfaces of bamboo.