Wayland Town Crier 4/9/12: Mosquito spraying program is canceled. Mother Nature is helping out with mosquito control this year. Citing abnormally dry conditions, the East Middlesex Mosquito Control Project has canceled its annual spreading of the biological larvicide, Bti, for the first time since the program started in 1987. Crews traditionally drop ground-up corn cobs coated with the pesticide in mid-April from helicopters hovering over wetlands in Framingham, Sudbury, Wayland, Weston and other parts of the 25-city-and-town service district.