枣-棉、苹果-棉间作模式下棉蚜种群发生差异的生态学机制

In recent years, the cultivated area of fruit trees become more and more, the intercropping patterns of jujube-cotton and apple-cotton become common planting patterns in the southern area of Xinjiang Autonomous Region. The data obtained from field investigation during 2014-2015 revealed that, the population abundance of Aphis gossypii markedly decreased in the jujube-cotton intercropping pattern, whereas they significantly increased in the apple-cotton intercropping pattern, the population abundance of A. gossypii showed obviously difference between two different planting patterns. Firstly, we investigated the population numbers of A. gossypii and its natural enemies, ascertained the difference of predators of A. gossypii in the intercropping patterns of jujube-cotton and apple-cotton. Secondly, we assessed the controlling efficacy of natural enemies towards A. gossypii via cage exclusion test. Thirdly, we sampled the predators of A. gossypii on the cotton and the fruit trees, and then ascertain the feeding habits of natural enemies by using PCR tests during two different planting patterns. On the basis of the above-mentioned study, it is expected to clarify the ecological mechanisms for the growing and declining of the population number of A. gossypii between jujube-cotton and apple-cotton, which will provide scientific evidence for controlling of A. gossypii under different intercropping patterns.

近年来，新疆南部地区果树栽培面积日益增加，枣-棉、苹果-棉间作成为较为普遍的种植模式。2014-2015年调查发现，枣-棉间作模式下棉蚜种群数量比棉花单作明显降低，而苹果-棉间作模式下棉蚜种群数量比棉花单作显著增加，两种间作模式下棉蚜种群数量呈现明显差异。本项目拟通过研究枣-棉、苹果-棉间作模式下天敌发生数量的差异，摸清两种种植模式下天敌的发生效应；通过田间罩笼试验，评估捕食性天敌及寄生性天敌对棉蚜种群的控制作用；采集枣-棉、苹果-棉间作模式下棉花和果树上的天敌，利用棉蚜的特异性引物对天敌进行PCR检测，明确枣-棉、苹果-棉间作模式下天敌对棉蚜的取食选择。通过上述研究，以期揭示新疆枣-棉、苹果-棉间作这两种种植模式下，棉蚜种群发生差异的生态学机制。为进一步解析南疆复合种植模式下害虫的发生与演替机制提供理论支撑，为发展不同间作模式下棉蚜种群控制对策提供科学依据。

新疆是我国的植棉大省，棉花生产在我国棉花种植业中已经占有相当重要的地位。南疆阿克苏地区枣-棉、苹果-棉间作模式较为普遍，栽培面积较大。但是目前对于枣-棉、苹果-棉间作这两种模式下害虫与天敌消长规律，及互作机理的研究仍然非常少、相关问题仍然不是很清楚。为此，本项目从景观生态学、种群生态学、分子生物学的手段对果棉间作模式下对棉蚜影响的机制进行了研究。得到了如下结论：（1）不同的间作模式棉蚜相应不同，枣棉间作棉田较棉花单作来说棉蚜种群数量减少；苹果棉间作棉田棉蚜种群数量增加。（2）枣棉间作棉田、苹果棉间作棉田分别较单作棉田来说增加了捕食性天敌和寄生性天敌的种群数量。（3）枣棉间作模式下间作棉田捕食性天敌控害指数没有显著的差异；苹果棉间作模式下捕食性天敌的控害与单作无显著差异。（4）利用棉蚜的特异性引物对天敌进行DNA进行PCR扩增，阐明枣棉间作、苹果棉间作捕食性天敌的检出率分别于单作棉田无显著差异。（5）枣棉间作模式下寄生性天敌对棉蚜的控制显著的高于单作田；苹果棉间作模式捕食性天敌取食选择试验表明，较捕食棉蚜来说捕食性天敌更偏好于取食绣线菊蚜。研究阐明寄生性天敌对枣棉间作棉蚜种群控制起到了关键作用；苹果棉间作模式捕食性天敌的取食偏好是导致苹果棉间作模式下棉蚜种群数量增加的关键因素。