Studies Of The Main Ecological Methods To Control Rice Pests

The efficiency management of the insect pests is one of the important agricultural practices in rice production. However, over use of insecticides will result in the increase of farmer's cost, environmental pollution and residue of pesticide in rice grain. This thesis concentrated on the main techniques minimizing the application of insecticides for controlling the major rice insect pests in rice based ecosystem of Ningbo, Zhejiang province. The following results were obtained:(1) Surfactant organo-silicate with the pesticides can improve the pesticide activities, and decrease the application dose of pesticides.(2) The synthetic sex pheromones were evaluated for trapping leaf folder Cnaphalocrocis medinalis and striped stem borer Chilo suppressalis in paddy field. The results showed that the synthetic sex pheromones lure have significant effects on trapping the two kinds of pests. The sticky wing trap captured more moths than universal moth trap. Sex pheromone lure could be the key technique in IPM of rice.(3) The rice-duck complex ecosystem had significant effects on the abundance of plant hoppers and their predatory spiders. This kind of system not only significantly reduced the population of plant hoppers, but also increased the number of spiders and can provide farmers with more economical benefits.(4) Based on the above research, four practices'bio-control, standard spray, farmer's spray and pesticide free'were compared to control the main rice insect pests. The results showed that the occurrence and damage of rice pests were most serious and the economic benefit decreased markedly when there was no pesticide spray during rice growth period. Standard spray and farmer's spray had similar effects on plant hoppers and the leaf rollers, rice yield and economic benefits. But the damage caused by the striped stem borer was highest in farmer's spray field. Moreover, the farmer's spray pattern had the worst effects on the environments. The biocontrol pattern (raising ducks in the paddy fields with few biopesticides usage) had some effects on controlling rice pests, but it is not so significant as the standard spray and farmer's spray patterns. However, the bio-control pattern got the highest economic benefits. Thus it is important to guide farmers to the ecological control of rice plantation.