The Investigation and Epidemic Study on Apple Diseases and Harmful Insects in Lijiang, Yunnan Province

Lijiang is an important apple growing area in Yunnan, where the occurrence of pests and diseases seriously affects the development of apple industry. In order to prevent and control diseases and insect pests effectively, we investigated the plant diseases and insect pests systematically and studied the epidemic rules at three main producing areas (Yulong, Gucheng and Ninglang) in Lijiang in three years. The results showed that there were 23 kinds of diseases, including 16 kinds of fungal diseases, three kinds of viral diseases and four physiological diseases. Among those diseases, rot, powdery mildew, brown spot disease and spot leaf spot were more severe of the diseases causing damage. The investigation results showed that rot disease incidence rate had obvious difference at three areas of Yulong,the ancient city and Ninglang, and it was the most serious at Ninglang; however, brown spot, spot disease and powdery mildew had not obvious difference at three above areas. Seasonal dynamics study results show that rot incidence rate was stable, powdery mildew began to occur early, brown spot, spot disease had a similar time dynamic rules, the incidence rate of rot disease and powdery mildew were increasing year by year, and the incidence rate of brown spots and spot disease had larger fluctuations year by year. Total 28 species orchard apple insect pests were investigated, of which, Eriosoma lanigerum,Myzus persicae and Panonychus citri were the relative serious pests. Generally,there was no serious occurrence in the whole, and there was slight difference and dynamic fluctuation among different areas and different years. The studies provide the basis for the development of apple industry in Lijiang, Yunnan, and provide evidence for the prevention and control of diseases and insect pests.