摘要： 本试验对苹果园种植覆盖作物—白香草木樨Melilotus albus Desr.后,苹果树上叶螨及其主要天敌—小花蝽Orius minutus(Linnaeus)、中华草蛉Chrysopa sinica Tjedet、塔六点蓟马Scolothrips sexmaculatus(Pergande)和拟长刺钝绥螨Amblyseius pseudo-longispinosus Xin et Liang等种群数量的消长进行了观察.6月中旬后,在生草法处理区,天敌与山楂叶螨Tetranychus　 viennensis Zacher之间的益害比明显地高于免耕法对照区.因此,山楂叶螨的种群数量明显下降.7月12日,处理区与对照区之间的差异最为显著,分别为每叶2.54头和每叶8.80头.在整个生长季里,只使用了一次杀螨剂.由此可见,果园内种植覆盖作物以保护和增殖天敌,是害虫综合治理的重要措施之一.

关键词: 捕食性天敌, 生草法, 山楂叶螨, 生物防治

Abstract: This experiment was conducted in the Tuanchenguoyuan Apple Orchard near Fragrant Hill Park, Beijing in 1985. The white sweet clover Mclilotus albus was grown as a cover crop between the rows of apple tree. The population dynamics of natural enemies,such as Orius minutus,,Chrysopa sinica,Scolothrips, sex-macnlatus and Amblyseius pseudolongispinosus, and the arthropod pests, such as Tetranychus viennensis, were observed. After the middle of July, the ratio of T.vicnnensis to its natural enemies on the apple trees was much lower in the cover cropping orchard than in the control orchards without the cover crop. On July 12, when the population of T. vienncnsis was most significantly different between the orchards with and without cover crop, there were 2.54 active mite stages per leaf and 8.80 active mite stages per leaf in test and control orchard respectively. During the entire growing season, miticide was applied only once. Obviously.cover cropping in apple orchards should be considered as one of important methods of IPM.

Key words: Predators, Cover cropping, Tetranychus viennensis, Biological control