作物多样性对大豆蚜的控蚜效应

【目的】研究大豆蚜发生为害及大豆与多种作物间邻作种植对大豆蚜的控制作用,为大豆蚜的可持续综合治理提供理论依据。【方法】采用系统调查的方法,研究大豆蚜和天敌田间种群动态;通过田间罩笼、人工接蚜和释放天敌的方法,研究捕食性天敌对大豆蚜种群的控制作用;在佳木斯地区进行大豆与早熟马铃薯间作,牡丹江地区进行黄瓜-大豆-玉米、甜葫芦-大豆-玉米、烟草-大豆-香瓜、甜菜-大豆-玉米等多作物带状穿插种植模式,以单作大豆田为对照,对不同种植模式的大豆田大豆蚜与天敌进行调查,研究作物多样性对大豆蚜的控制作用。【结果】2009年6月中下旬大豆蚜开始侵入大豆田,3~5周后田间有蚜株率达到100%,大豆蚜种群发生高峰期在7月下旬至8月上旬,9月上旬在田间逐渐消失。草蛉、瓢虫和寄生蜂等为蚜虫天敌优势种;按大豆蚜与天敌数量之比700︰1,释放异色瓢虫和叶色草蛉成虫7 d后,蚜虫种群减退率分别为54.78%和78.79%;大豆与早熟马铃薯间作,在大豆蚜种群迅速增长期早熟马铃薯收获(7月20日)后第5天,豆田蚜虫天敌总数是收获前的2.6倍,与同期单作大豆田相比,间作田大豆蚜种群数量降低了51.3%。大豆与甜葫芦、香瓜、烟草和玉米等作物进行多样性间作种植,在大豆蚜田间发生高峰期,单作豆田益害比为1︰65.2,多样性种植区的大豆田益害比为1︰26~1︰42,与单作大豆田相比,间作田大豆蚜种群数量降低40.7%~83.5%。【结论】2009年大豆蚜的种群高峰期为8月3日,田间的天敌优势种类为草蛉、瓢虫和寄生蜂。早熟马铃薯与大豆间作,在大豆蚜种群迅速增长期间收获早熟马铃薯,大量蚜虫天敌转移至间作的大豆田,从而形成对大豆蚜的控制。大豆与其它经济作物间邻作,大豆田天敌昆虫与蚜虫的益害比明显提高,表明利用农田作物多样性能充分发挥自然天敌的生物控害作用。

Crop diversification as a method of managing the soybean aphid,Aphis glycines Matsumnra

Objectives] To determine the benefit of intercropping soybeans as a means of controlling the soybean aphid, Aphis glycines Matsumura. Methods] Field surveys of the population dynamics of the soybean aphid, A. glycines and its natural enemies were conducted in 2009. A field experiment using cages artificially infested with 500 aphids per plant into which naturalenemies were released was conducted to study the ability of indigenous predators to reduce the soybean aphid population. To study the influence of crop diversity on soybean aphids and their natural enemies, soybeans were intercropped with different crops at two sites in Heilongjiang Province, early maturing potato at Jiamusi, and Lagenaria spp., Cucumis melo, Nicotiana tabacum and Zea mays at Mudanjiang. Results] Aphids colonized soybeans in mid-late July, and infestation reached 100% after 3 to 5 weeks. The population peak occurred from late June to early August, and aphids began to disappear in early September. The dominant species of natural enemies were mainly lacewings, ladybugs and parasitoids. Releasing adult Harmonia axyridis and Chrysopa phyllochroma at a ratio of 700 aphids ： 1 natural enemy, resulted in rates of soybean aphid decline of 54.78% and 78.79%, respectively after 7 days. In the fields intercropped with early maturing potatoes, natural enemies increased by 2.6 times 5 days after potatoes were harvested and the soybean aphid population decreased by 51.3% in intercropped fields compared to soybean monocultures. In soybean fields intercropped with different crops, the ratio of natural enemies to soybean pests was 1 ： 65.2 in soybean monocultures compared to 1 ： 26 to 1 ： 42 in intercropped fields and the soybean aphid population was 40.7% to 83.5% smaller in intercropped fields. Conclusion] The soybean aphid population peak was on 3, August in 2009. The dominant species of natural enemies were mainly lacewings, ladybugs and parasitoids. In fields in which soybeans were intercropped with early maturity potatoes, some natural enemies migrated to soybean plants after the potatoes were harvested significantly reducing the population of soybean aphids. The ratio of natural enemies to soybean pests was much higher in soybean monocultures than in intercropped fields, suggesting that crop diversity can facilitate the bio-control of soybean aphids by their natural enemies.