Abstract
The effect of different humidities on the development of Aniblyseius deleoni MUMA et DENMARK was examined. Most of the eggs were unable to hatch at relative humidities lower than 56% at 20°C. The high mortality of immature stages was observed at 70-75% R. H. at 25°C and their developmental period was longer than that at 85-90% R. H. The effect of humidity on the ability of predators to regulate the mite populations, Panonychus citri MCGREGOR, was examined at 55-60, 65-75 and 85-90% R. H. at 25°C in the growth cabinet. When the initial ratio of predators to preys was 1 : 20, the predator suppressed the prey populations within 21 days at 85-90% R. H., but no suppression was observed at lower humidities than 65-75% R. H. The increasing rate of the predator population at 65-75% R. H. was slower than that at 85-90% R. H.
