Field evaluation of deet and a piperidine repellent against Aedes communis(Diptera : Culicidae) and Simulium venustum (Diptera : Simuliidae) in the Adirondack mountains of new York

Repellent efficacy of N,N-diethyl-3-methyl-benzamide (deet), the piperidine , 1-[3-cyclohexen-1-ylcarbonyl]-2-methylpiperdine (AI3-37220), and a 1:1 ra tio of deet + AI3-37220 were evaluated topically (0.25 mg/cm(2) applied in ethanol solution) on human volunteers against the mosquito Aedes communis ( DeGeer) and the black fly Simulium venustum Say. The average repellency of all three formulations was >95% at 4 h. For both mosquitoes and black flies , deet alone provided <90% protection at 6 h, whereas AI3-37220 provided >9 5% protection: Although repellent treatments were not significantly differe nt overall, the contrasts between AI3-3720 versus deer were significant at 6 and 8 h. The 95% confidence interval on percent repellency at 6 h ranged from 90.1 to 98.9% for AI3-37220 versus 64.3 to 82.2% for deet, and at 8 h ranged 76.1 to 88.5% for AI3-37220 versus 47.8 to 64.0% for deet. Similarly , the confidence interval for protection against black flies at 6 h by (AI3 -37220 ranged from 86.3 to 99.5% and did not overlap with the confidence in terval provided by deet alone (51.2 to 78.8%). There was no evidence of syn ergistic repellency from a combination of the two compounds; i.e., protecti on from combined compounds was no better than either repellent used alone.