| In recent years, rice main insect pests and diseases took place severely, threatening the production of rice. Accompanied by this, a lot of pesticides were misused, which results in environmental pollution and the decline in quality of farm products. To control the rice pests safely and effectively, we studied the population dynamics of the rice main pests and their chemical control techniques in Huang Yan District, Zhejiang province. The results are as follows:1. Population dynamics of rice main pests in Huang Yan division has much changed recently. For insect pests, the number and the damage levels of rice leaf folder (RLF) Cnaphalocrocis medinalis and rice planthoppers were increased, whereas the population number and the damage levels of the rice stripped stem borer (SSB) Chilo suppressalis, Naranga aenescen, Nephotettix bipunctatus were decreased. For rice diseases, rice damage caused by rice sheath blight disease rhizoctonia solani were increased, while damage by rice blast pyricularia oryzae, rice bacterial stripe Xanthomonas oryzae pv. oryzicola and bacterial blight of rice Xanthomonas campestris pv. oryzae were decreased. The main factors causing this shift were a change in cultivation system, diversification of habitats in the field, increases in temperature in spring and winter, and pest resistance to pesticides.2. Population dynamics of rice main pests in single-crop rice with transplanting or direct seeding was investigated. The results showed that the number of RLF, rice planthoppers and spides, and the damage caused by rice sheath blight disease were higher in transplanting rice than in direct seeding rice; the peak time of the number of SSB was earlier in direct seeding rice than in transplanting rice, but no difference was found in damage levels by SSB between them.3. To select effective pesticides for RLF, field experiment was carried out. The results show that Fipronil is effective for controlling RLF when 30-40ml was applied in 667 m2.3% Fipronil-triazophos is another kind of effective pesticide for RLF, however the amount applied should increase with the increase in larval instar: 60 ml per 667m2 for controlling young larvae, whereas 70 ml per 667m2 for controlling old larvae.4. We also did field experiments for choosing effective pesticides for rice brown planthopper, Nilaparvata lugens. The results show that 40% chlorpyrifos (80ml per 667m2) mixed with 25% buprofezin (50g per 667m2) is effective for controlling N. lugens adults and nymphs, and its effect could last for a long time.5. Effectiveness of 40% Foggo for rice insect pests was investigated. The results showed that Foggo is an effective pesticide for RLF and rice planthoppers. In the early stage in single crop rice, we could apply Foggo to mainly control RLF, concurrently controlling rice planthoppers and SSB; in the later stage, Foggo could be used to mainly control rice planthoppers and synchronously control the leaf folder and SSB. Foggo should be applied when the herbivores were at young larval stage, and 8-10 g of 40% Foggo WG per 667m2 was suitable.6. Four kinds of instruments for spraying of pesticide, together with three doses of pesticides were tested for effectiveness of rice planthoppers at rice later stage. Since the plants are tall at the later stage, it's suitable to promote the application of stretcher type's motorized sprayer; advantages of new or old hand sprayers are shown out with the increase in pesticide dose. At the later period of single cropping rice, using mist prayer was not as effective as were other three sprayers, so it is not suitable for application at rice later stage.7. A project on reducing applied pesticides and enhancing control effectiveness in rice was organized and implemented in Huang Yan District. From 2006-2008,12600 hm2 of rice fields were used for implementation of this project. Through the implementation of the project, the amount of pesticides applied was significantly reduced, and the famer's benefit was increased.
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