Investigation on Walnut Main Diseases and Insect Pests in Hanyuan County, Sichuan Province

In order to investigate the walnut diseases and insect pests, a field investigation was carried out in the artificial walnut plantation in Hanyuan county of Sichuan province. The main results were as follows: 1) There were 30 kinds of walnut insect pests in Hanyuan County, among which the more serious pests were Batocera horsfieldi, Culcula panterinaria, Cnidocampa flavescens, Dichocrocis punctiferalis, Atrijuglans hetaohei, and so on. The common diseases were walnut anthracnosc, walnut black spot, walnut leaf defect. The more potentially harmful pests were walnut wood rot, walnut branch blight, walnut canker, Anoplophora chinensis and Rosalia lameerei, which were harmful to walnut branches. 2) Harmful species of walnut insect pests changed periodically with the change of temperature. When the temperature was 10～30 ℃ in April, the insect pests began to harm the plant, and the disease also began to infect plants. With the increase of temperature, the pests species increased and the harm became more serious. When the temperature was 10～20 ℃ in November, the harmful degree of insect pests decreased and pests began to overwinter. 3) The harmful species and harmful degree of walnut insect pests were related to the planting environmental factors. The harmful degree of pests in mixed plantation of walnuts and four-side trees and walnuts and corn was more serious than that of pure walnut plantation. There were more kinds of harmful organisms in mixed cultivation of walnuts and citrus trees than in pure walnut plantation. This phenomenon might be related to the common harmful pests among mixed plants, and the relevant mechanisms should be further studied.