生草模式对苹果园天敌及其调控苹果绣线菊蚜作用的影响

本文采用田间系统调查和罩笼试验评价天敌控害作用，分析生草模式对苹果园天敌及其控害功能的影响，为合理利用地面植被控制绣线菊蚜提供科学依据。结果表明，地面植被会影响苹果园天敌的种群发生数量；人工生草苹果园捕食性天敌和寄生性天敌的种群密度均显著高于自然生草园和清耕苹果园；直接调查法获得的天敌与绣线菊蚜的益害比差异不显著，黄板调查的结果显示，人工生草园益害比显著高于自然生草园和清耕园，分别是其3.2倍和22.88倍；罩笼试验结果表明，第15 d罩网处理和开放处理间苹果绣线菊蚜的种群增长比率无显著差异，但清耕园苹果绣线菊蚜的种群增长比率显著高于人工种草和自然生草苹果园；三种处理苹果园生物控害指数无显著性差异。果园生草能显著提高天敌的密度及益害比，在提高果园天敌数量和控害功能方面具有重要作用。

Effects of Grass-growing Patterns on the Population Dynamics of Natural Enemies and Management of Aphis citricola in Apple Orchards

Population dynamics of natural enemies and effects on Aphis citricola Vander Goot in apple orchards were analyzed through systematic scouting and cage tests to support the rational use of ground vegetation in management of A. citricola. The analysis results showed that the ground vegetation affected the population of natural enemies in apple orchards. Densities of predators and parasitoids were significantly higher in grass-growing orchards than in natural grass orchards and clear cultivation orchards. Direct scouting showed no significant difference in the ratio of natural enemies to A. citricola between different apple orchards, while investigation using yellow sticky traps showed significantly higher ratios of natural enemies to A. citricola in grass-growing orchards than in the natural grass orchards and clear cultivation orchards, which was 2.2 times and 21.88 times more, respectively. Cage tests indicated no difference in the relative growth rates of A. citricola between the open treatment and the treatment caged on the 15^th days after trial. But A. citricola increased more in clear cultivation orchards than in grass-growing orchards and natural grass orchards. The biocontrol services index of natural enemies to A. citricola was not significantly different between the three treatment orchards. These results provide evidence that grass-growing in apple orchards can significantly increase the density of natural enemies and the ratio of enemies to A. citricola and plays an important role in pest management.