Status of insecticide resistance in anopheline mosquitoes of Punjab Province, Pakistan.

Susceptibilities of six anopheline mosquito species from nine localities in Punjab Province to DDT, dieldrin, malathion, fenitrothion, fenthion and propoxur were determined. DDT-resistance was found in An. annularis, An. culicifacies, An. stephensi and An. subpictus but An. nigerrimus and An. pulcherrimus were susceptible to DDT. Association between DDT-resistance and endophilic habit of the mosquitoes has been observed but needs further confirmation. Dieldrin resistance was present in all the six species. Five species were susceptible to malathion, and only An. stephensi showed incipient malathion resistance without cross resistance to other organophosphates. The six species were susceptible to fenitrothion and propoxur. An. nigerriums and An. subpictus showed some evidence of resistance to fenthion, the remaining four species were fenthion-susceptible.

Selection for DDT-susceptibility in Anopheles culicifacies from Lahore, Pakistan.

Two colonized and three wild strains of Anopheles culicifacies were screened to isolate a DDT-susceptible colony. No susceptible strain was isolated, as the colonies tested were either homozygous or nearly so for resistance. A more rigorous selection of a highly DDT-resistant strain suggested the involvement of ancillary factors in addition to major genes for DDT-resistance in the species.