A comparison was made on application characteristics between a sprayer with twin-fluid nozzle and conventional sprayers for PCO's (pest control operators). It was found that the application characteristics of Actisol sprayer were superior to those of such conventional sprayers as a compressed air sprayer and an aerosol sprayer in respect to the penetrating perfomance and the deposition efficiency of spray droplets in structural wall clearances used by cockroaches and other insect pests as their harbourages. Actisol sprayer is considered to be suitable for the agriculture area (for instance, green houses) because it is small and portable in spite of a compressor in its system, and applies chemicals by dry treatment. It appears, additionaly, that Actisol sprayer may be used as an electrostatic sprayer because its output corresponds to very low volume or ultra low volume application.