FACTORS AFFECTING THE OUTBREAK AND DAMAGE OF THE BROWN PLANTHOPPER,NILAPARVATA LUGENS (STAL) IN THE PADDY RICE FIELDS OF ZHEJIANG PROVINCE
影响褐飞虱猖獗和为害的因素

The brown planthopper (BPH) can not hibernate in the paddy rice fields of Zhejiang Province as we observed previously, so its population is increased fundamentally by the immigrants.In order to survey the macropterous adults' immigration,we set up a group of net traps directed to S,SW, W,NW, N,NE,Eand SE respectively on the top of a high mountain, 28°43'N, altitrde 1338 m in Quizhou County ard another group in Zhoushan archipelago, 30°N, 122°20'E, 271m. Observations started from 1977 to 1983 have shewn that...