Studies On Stimulating Effect Of Two Selective Insecticides On The Reproduction Of Rice Yellow Borer,Tryporyza Incertulas(Walker)and Their Effects On Biochemistry Of Rice Plants

The thesis reviewed the research progress on resurgence of insects, effects of pesticides on physiology and biochemistry in plants, especially in rices, and occurrence of rice yellow borer(RYB), Tryporyza incertulas (Walker) after 1950 in China. For the reason that RYB occurred heavily in recent years, this study approached the relationship between the pesticides and the reproduction of the non-target insects RYB, including stimulating effect of buprofezin and imidcloprid on the numbers of egg laid by rice yellow borer, Tryporyza incertulas (Walker) of, testing the biochemistry in treated rice plants, the Vitellogenesis (Vg) content in the ovary of RYB, the JH-titre in female RYB moths, and so on.The results showed that the reproductive rate of emergence moths during the larvae feeding on the rice plants of Xiushui 63 treated with the two insecticides was significantly higher than that of control, indicating the numbers of egg laid by the borer were stimulated following buprofezin and imidcloprid applications. However, There was no such effect for the larvae feeding on rice variety Zhendao 2 which showed moderate resistance to the insect. In addition, the incidence of stimulating egg laid for the first instar treated with the two insecticides was greater than that that of for the third instar. Biochemical tests showed that oxalic acid concentration declined, and photosynthetic rate of rice leaves following the two insecticides applications declined significantly compared to control, whereas reducing sugar concentration increased significantly for all other treatments of two varieties except Xiushui 63 treated with buprofezin. Level of glutathione-S-transferase varied with rice variety and insecticide. And there was no different dominant band presented by SDS-PAGE between Vg of female moths during the larvae feeding on the treated rice plants and that of control. The Vg content in the ovary of moths during the larvae feeding on the rice treated with buprofezin was also significantly higher than that of control, and the Vg content of moths feeding on the imidcloprid treated rice did not so. Furtherly the Vg content of moths living on the rice plants, treated with pesticides when RYB was elder larvae (4 instar), was highest in those of treated and control. The JH-titre in the moths fed on the pesticides-treated-plant was significantly higher than that of control. Since 1990's theratio of the third generation adults of RYB to the second generation adults under light trap was significantly higher than that before 1990's.