Experiments on prevention and control of Dendrolimus superans by using 20% Mie'A wettable powder

The experiments were conducted in Larix principis-rupprechtii plantations from Aug. to Sep. in 2001 in Keshiketeng Banner Huamugou forestry farm in Chifeng city. The results indicated that: the effects of prevention and control of Dendrolimus superans were remarkable by using 20% Mie'A wettable powder to conduct common spray and dust sprinkling on the surface of fields. The decreasing rate of Dendrolimus superans was over 97% by using the dosage of 450-750 g·hm -2 of chemicals to conduct common spray; the decreasing rate of Dendrolimus superans was over 90% by using the dosage of 600-900 g·hm -2 of chemicals to conduct common dust sprinkling; the control effect of common spray was better than common dust sprinkling.