烟田烟蚜种群动态与天敌作用的变化

对1999年、2007年云南玉溪地区烟蚜种群动态与天敌种类、作用进行了对比分析.结果表明:烟蚜的种群数量、动态均呈单峰曲线,在7月上中旬密度最大,但无论是烟蚜的日增长率还是平均数量,1999年均高于2007年.烟田内烟蚜的主要天敌有烟蚜茧蜂(Aphidius gifuensis)、蜘蛛类、瓢虫(Coccinella septempunctata,Harmonia axyridis)、黑带食蚜蝇(Episyrphus balteatus)和草蛉(Chrysopa sinica).烟蚜茧蜂、瓢虫、食蚜蝇和草蛉与烟蚜具有一定的跟随关系,而以烟蚜茧蜂的跟随关系最为明显.通过相关与通径分析得出,影响烟蚜种群数量变化的天敌主要有烟蚜茧蜂、瓢虫和草蛉,但随着时间的变化,各天敌对烟蚜的控制作用亦发生了变化.由于长期实施以烟蚜茧蜂防治烟蚜为主体的烟蚜综合治理措施,烟蚜茧蜂已成为当地控制烟蚜种群数量的重要天敌.

Changes of Population Dynamics of Myzus Persicae and Effects of Its Natural Enemies in Tobacco Fields

The population dynamics of Myzus persicae and the effects of it natural enemies were studied in Yuxi, Yunnan province respectively in 1999 and 2007. The population dynamics of Myzus persicae presen-ted unimodal curves in both years, but either daily increasing rates or average numbers of Myzus persicae in 1999 is higher than that in 2007. Aphidius gifuensis, spiders, ladybirds (Coccinella septempunctata and Harrnonia axyridis), Episyrphus balteatus and lacewings (Chrysopa sinica) were predominant natu-ral enemies for Myzus persicae and all natural enemies showed following relations with Myzus persicae, but Aphidius gifuensis was the most correlative. The results of correlation and path analysis showed that Aphidius gifuensis, ladybirds and lacewings were the main natural enemies affecting population dynamics of Myzus persicae, but the effect of each natural enemy was different as time changed. Because of its long-term release for suppression of Myzus persicae, Aphidius gifuensis has become the most important natu-ral enemy for Myzus persicae in tobacco fields in Yuxi, Yunnan province.