过去 ,玉米叶螨在山西忻州属偶发性害螨 ,2 0世纪 90年代后 ,发生频率显著增多。 2 0 0 1年 ,玉米叶螨在忻州市大发生 ,被害作物有玉米、高粱、谷子、豆类、棉花、向日葵、蔬菜、瓜类和花卉等 ,发生面积约 10万ｈｍ2 。其特点为发生早 ,危害时间长 ,螨株率高 ,螨量大 ,是 5 0多 In the past, corn spider mites in Xinzhou, Shanxi is a sporadic pest mites, 20th century, 90 years after the occurrence of a significant increase in the frequency. In 2001, corn spider mites were found in Xinzhou City. The crops were maize, sorghum, millet, beans, cotton, sunflower, vegetables, melons and flowers. About 100,000 hm2 of land was harvested. It is characterized by occurrence of early, endangering a long time, high rate of mites, mites, is more than 50