Control function of spider community to planthopper in the rice field
稻田蜘蛛群落对稻飞虱的控制功能作用研究

Based on the experimental data from Anqing City,Anhui Province in 1996 and Jiangpu County,Jiangsu Province in 1997,the natural control functions of spider community to rice planthopper were studied by using two indexes,the capacity of environment( K )and reproduction rate The enemy function index( EF ) its formula were put forward firstly The results showed that there was significant negative correlation between the EF value and rice injured rate by planthopper The K value and reproduction rate of rice planthopper population increased greatly as the beginning EF value decreased EF index could show the control function of enemies to planthopper clearly in the different period