<正>乡村债务由来已久,日益严重的乡村债务问题,不仅严重影响农村社会稳定,也成为构建和谐社会和当前新农村建设中的一大障碍。切实化解历史债务、坚决防

Taxis responses of Microplitis mediator (Haliday) to the volatiles of cotton plants at squaring stage induced separately by mechanical injury (treatment A), damage of cotton bollworm (CBW) Helicoverpa armigera (Hubner) (treatment B), steaming with salicylic acid (SA) (treatment C) and treatment A plus oral cavity secretion of CBW (treatment D) were tested in a Y-tube olfactometer. The results showed that treatment B, treatment B plus larval H. armigera, and treatment C had significant attraction for M. mediator, and there were no obvious differences in the attraction of these treatments. Also, there was no obvious attraction of healthy cotton plant, treatment A, treatment D for this parasitoid. The qualitative and quantitative analyses of the cotton volatiles of different treatments were conducted by using GC-MS, and the results indicated that the kinds and contents of cotton volatiles from treatment B, treatment B plus larval CBW and treatment C were more than those of healthy cotton plant, and the differences among those of treatment A and treatment D and healthy cotton plant were not obvious. In comparison with healthy cotton, the contents of β-myrcene, α-pinene and β-pinene were significantly higher, and that of limonene from cotton of treatment C changed obviously. Fig 2, Tab 1, Ref 19