Comparison of the synthetic pyrethroids Esbiothrin and Bioresmethrin with Scourge and Cythion against adult mosquitoes in a laboratory wind tunnel.

Both candidate adulticides, Esbiothrin and Bioresmethrin, exhibited quick knockdown 1-h posttreatment. Esbiothrin elicited the fastest knockdown, but Bioresmethrin was more effective at both 1- and 24-h posttreatment than either Esbiothrin or Scourge against both Aedes taeniorhynchus and Culex quinquefasciatus. Mosquitoes treated with Scourge required more time and a higher dosage to respond in a physiological manner similar to those treated with either of the candidate adulticides. More than twice the dosage rate of Cythion was required than either candidate adulticide to cause a similar physiological response in treated mosquitoes.

Evaluation of three candidate cypermethrin-piperonyl butoxide formulations compared with Scourge against adult Culex quinquefasciatus.

Cypermethrin-piperonyl butoxide formulations (1:1, 1:5, 1:10) were evaluated in a laboratory wind tunnel against colony reared, susceptible adult Culex quinquefasciatus mosquitoes. Scourge (4% resmethrin:12% piperonyl butoxide) was used as the standard for comparison. Based on the LC90 data, the 3 cypermethrin-piperonyl butoxide formulations were 2.6-3.7x more toxic than Scourge 24-h posttreatment.

Small plot test of sustained-release Altosid (methoprene) pellets against Aedes taeniorhynchus in brackish water.

Four percent methoprene pellets applied at a rate of 2.2 kg/ha effectively controlled adult Aedes taeniorhynchus emergence (93%) for over 3 weeks. Efficacy declined to 38% 4 weeks posttreatment. At a rate of 4.5 kg/ha, 95% control was maintained for 34 days with the exception of the 5th week when only 72% control was observed.

Insecticide tolerance of Culex nigripalpus in Florida.

Larval susceptibility tests of Culex nigripalpus populations from various areas of Florida have shown resistance to several organophosphorus insecticides since 1984. Although the degree of resistance is low (2 to 7 times), it can be termed tolerance and appears to be the greatest for fenthion, followed by temephos, naled and malathion. It is suggested that pesticide runoff from lawns, golf courses and agricultural and urban areas may play a role in developing resistance in Florida mosquito populations.