巍山县核桃蚜虫天敌优势种研究

In order to clarify the occurrence of natural enemies of Juglans sigillata aphid, find scientific guidance for prediction and utilizing natural enemies to prevent and control of aphids, this study established a monitoring experimental area to study the population dynamics and the occurrence of natural enemies.The results showed that the peak period of aphid occurrence was from late May to early June, and there was only one peak period throughout the year. The main natural enemies were Harmonia axyridis, Coccinella septempunctata, Propylaea japonica (Thunberg), Episyrphus balteatus De Geer, Aphidius gifuensis Ashmead and Semachrysa. The Coccinellidae was the dominant natural enemy, and Harmonia axyridis was the dominant species with a dominance index of 0.494 7. The population of Harmonia axyridis had a close following effect with the population of aphids. The population number first increased with the number increase of aphids, and then decreased with the number decrease of aphids, which reached the peak later than the occurrence of aphids, and was consistent with the following effect of predator pests.