间作芳香植物对苹果黄蚜及其天敌异色瓢虫的生态调控机制

Aromatic plant volatile secondary substances as information transfer materials play a crucial role on pests ecological regulation in orchard ecological system. Three aromatic plants, Satureja hortensis L., Tagetes patula L. and Ocimum basilicum L., were selected as intercrops and clean cultivation as control in apple orchards to test the effects of intercropping aromatic plants on the population, the space distribution and temporal characteristics of spirea aphid and its natural enemy harmonia axyridis.The ecological relationships of spirea aphid and its natural enemy harmonia axyridis are analyzed, and the relationship of spirea aphid and its natural enemy harmonia axyridis dynamic model was established in different aromatic plants intrecropping plots. The differences were compared among different plots, and a most suitable aromatic plant specie was selected out to regulation the occurence of spirea aphid and its natural enemy harmonia axyridis on the basis of above results. The method of H S-SPME-GC-M S was used to separate, purify and identify of the volatile substances of aromatic plant (A) and fruit tree leaves before and after the aphids feeding. The source, type, properties and content of volatile substances of aromatic plant that have the role of regulation spirea aphid and its natural enemy harmonia axyridis were determined. And then we using four pathways and "H"smell instrument to test the effects of the volatile chemical composition of the aromatic plant on spirea aphid fecundity and the behavior of harmonia axyridis looking for host and prey. Through comprehensive analysis, we revealed the ecological regulation mechanism of intercropping with aromatic plants on spirea aphid and its natural enemy harmonia axyridis in apple orchard to provide the theory basis and technical for the ecological regulation of spirea aphid.

芳香植物挥发性次生物质作为果园生态系统中的信息传递物质, 对害虫的生态调控起至关重要的作用。本研究以苹果园为对象，分别设置果树行间间作薄荷、孔雀草、罗勒处理区，以清耕为对照，首先，测试间作芳香植物条件下苹果黄蚜及其天敌异色瓢虫组成、空间分布和时序特征，分析苹果黄蚜、异色瓢虫与节肢动物群落的生态关系，建立苹果黄蚜与异色瓢虫分布及相互关系动态模型，确定作用显著的芳香植物种类A；其次，采用顶空固相微萃取-气相色谱/质谱法对蚜虫取食前后苹果叶片及芳香植物A挥发性物质进行测定分析，确定芳香植物间作条件下对苹果黄蚜及异色瓢虫有调控作用的主要挥发性活性物的来源与种类；第三，利用多通路和"H"嗅觉仪测试与分析芳香植物A挥发性活性物对苹果黄蚜趋向、繁殖力，异色瓢虫寻找寄主与捕食行为及其两者相互关系的作用效应。据此，初步揭示苹果园间作芳香植物对苹果黄蚜及异色瓢虫的生态调控机制。

本研究以苹果园间作孔雀草、藿香蓟、猫薄荷3种芳香植物为处理，自然生草为对照，研究了间作芳香植物对苹果园节肢动物群落及主要类群的组成、时序、多样性的影响，重点研究了主要害虫苹果黄蚜及其天敌异色瓢虫的生态调控机制。结果表明，苹果园间作芳香植物显著降低了节肢动物总群落、植食性类群、苹果黄蚜的个体数量，其中以猫薄荷或含有猫薄荷的间作区效果最为显著。间作芳香植物显著增加了捕食性类群、苹果黄蚜的天敌类群及异色瓢虫的个体数量，其中以孔雀草或含有孔雀草的间作区效果作为显著。据此研究了苹果黄蚜及异色瓢虫分别对猫薄荷、孔雀草的行为反应，结果表明猫薄荷、孔雀草对苹果黄蚜具有显著的趋避作用，而对异色瓢虫在特定条件下具有显著的吸引作用。通过对猫薄荷、孔雀草挥发性物质进行分析，确定了其共同主要物质为柠檬烯与萜品油烯，进一步对异色瓢虫行为试验表明，低浓度柠檬烯或高浓度萜品油烯对异色瓢虫具有显著的吸引作用，但高浓度柠檬烯对异色瓢虫具有趋避作用。柠檬烯与萜品油烯1:1混合可以降低高浓度柠檬烯对异色瓢虫的趋避作用，提高低浓度萜品油烯对异色瓢虫吸引作用。本研究结果表明间作芳香植物可以通过化学趋避作用显著降低果园植食性害虫数量，尤其是苹果黄蚜的发生数量，同时通过化学诱集、栖息生境交替补充等作用显著增加异色瓢虫以及其它主要天敌的数量，从而有效地控制害虫的发生量，对进一步研究利用芳香植物进行果园害虫生物防治具有重要意义。