Studies on Residual Effect of 4 Insecticides for the Control of JE Vectors

The studies on residual effect of 4 insecticies; alphacypermethrin, permethrin, lambdacyhalothrin and pirimiphos methyl for the control of JE vectors; Culex tritaeniorhynchus, Culex fuscocephala and Culex gelidus at Ban-Nongpayome, Thambol Chumsong-songkram, Amphur Bang-rakum, Phisanulok province were carried out. The results showed that after two applications, with SEMCO compressure sprayers at 20 days interval of lambdacyhalothrin at the dosage rate of 0.186 g ai/m 2 killed 93.3% and 80.0% of JE vectors with cone bioassay on woods and nets surface respectively at 53 days and decreased JE vectors density of 93.3% by sweep nets at 53 days and 95.3% by suction tubes at 41 days after the treatment. Alphacypermethrin at the dosage rate of 0.177% g ai/m 2 showed 82.4% and 81.4% mortality rate by cone bioassay on woods and nets surface respectively and reduced 68.8% and 86.6% of density by sweep nets and suction tubes at 41 days after the treatment. Permethrin at the dosage rate of 0.165 g ai/m 2 showed 84.6% and 96.1% mortality rate by cone bioassay on woods and nets surface respectively at 28 days and reduced density of 70.3% by sweep nets at 53 days and 81.3% by suction tubes at 41 days after the treatment. Pirimiphos methyl at the dosage rate of 4.36 g ai/m 2 had 79.5% and 88.2% mortality rate by cone bioassay on woods and nets respectively at 28 days and could reduce density of 77.0% by sweep nets and 90.8% by suction tubes at 13 days after the treatment. The percent parity of mosquitoes collected from 4 treated areas showed 0-5% at 13 days after the treatment while the rate in the areas without any treatment was 25-35%. Key words: Residual insecticides, JE Vectors control