分析了辽宁省20余年来稻水象甲Lissorhoptrus oryzophilus种群密度数据,从田间可检出量到经济危害水平量只需几年时间,达到高密度种群数量仅需10年左右时间;之后在多数发生地区回复到经济危害水平数量上下,而在部分严重发生地区种群数量经几年下降到极低水平.根据昆虫种群波动理论并结合调查数据分析认为,严重发生地区种群迅速下降的主要原因是持续多年的高强度化学防治,天敌等因素制约其种群发展达到一定生态平衡,多数年份越冬期间的干燥气候也对越冬成虫的存活不利;而其他地区种群一直以低密度状态平稳波动是由物种在本地的生态特征所决定的.该结果预测,在持续放松化学防治现实情况下,经几年,辽宁省稻水象甲还会再次大发生.%This paper mainly analyzed the occurrence of rice water weevil,Lissorhoptrus oryzophilus on popula-tion density in two decades combined with the survey data. Only several years were requried from the detecta-ble level to economic injury level (EIL)in the field,and ten years were needed to reach the highest popula-tion density;subsequently,most area fall to the EIL,but partial heavy area declined to an extremely low lev-el. Base on the fluctation theory of insect,the principal reason of the population density decline among heavy area is under a high stress of chemical control year after year,the constraint factors such as the amount of nat-ural enemy regulate the rice water weevil and they both reach an ecological balance;In most cases,the meet with high temperature and low humidity during adult overwintering period is adverse for the survival rate;smooth and steady fluctation in a low density status is chosen by local biological characters in some other area. In brief,we forecast that the rice water weevil of Liaoning Province could outbreak again in the years to come, if still under a status of sustained loose and comfortable chemical control.
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