Investigation on Population Dynamics of Nilaparvata lugens in Organic Rice Field

In this paper,the population dynamics of Nilaparvata lugens and spider in organic rice field were investigated.Nine days after transplanting,the population density of Nilaparvata lugens was only 17 heads per 100 plants;29 days after transplanting,the population density of this pest insect increased to 301 heads per 100 plants,among them there were 281 heads of 1～2 instar nymphae.The occurrence quantity of Nilaparvata lugens in organic rice field was significantly lower than that in conventional rice field,while the quantity of spider in organic rice field was markedly higher than that in conventional rice field.