A modified CDC miniature light trap and a hand-held battery powered aspirator were compared for collection of Psorophora columbiae for use in laboratory and field test. No significant differences were found in mosquito mortality between the collection methods at 1, 12 or 24 hr posttreatment in the laboratory test or a 1 hr posttreatment in the field tests. Both methods proved viable alternatives for collection of Ps. columbiae. Posttreatment handling techniques in field test were investigated to determine if significant differences in mortality existed between mosquitoes transferred 15-20 min posttreatment to clean holding cages and mosquitoes which remained in the treatment cages after insecticide exposure. Synthetic pyrethroid, carbamate and organophosphorus insecticides were used against Anopheles quadrimaculatus. No significant differences in mortality existed between mosquitoes handled by the 2 techniques when treated with resmethrin. Significant differences were found in mosquito mortality between the 2 techniques when the treatments were bendiocarb and malathion. It is important to consider handling of the mosquitoes after treatment when comparing results of field tests involving caged mosquitoes, as different handling techniques influence levels of mortality.