Males ofSynanthedon pictipes(Grote and Robinson) were released at 4 distances downwind of female pheromone traps. The recovery was 67% at 100 m and decreased gradually to 40% at 800 m. Findings from diffusion and probit theory were combined to derive a linear relationship between log of distance and probit of percent recovery that described the data. Various effects of wind velocity and associated turbulence on insect pheromone communication are briefly discussed.