【摘要】 本文应用昆虫生命表方法在阳江县海陵岛研究稻纵卷叶螟种群数量动态问题。试验自1976年开始,至1981年积累了6年第二世代稻纵卷叶螟生命表的数据。通过生命表的组份分析,说明了海陵岛于1976—1981年间贯彻执行的综合防治措施是合理的,是6年来第三世代以后不致达到为害水平的重要原因;说明了天敌对第二世代稻纵卷叶螟种群数量起着重要的抑制作用;通过分析,找出了对稻纵卷叶螟第二世代种群数量起主要作用的因素和对种群数量起关键作用的因素。该项研究为进一步建立海陵岛第二世代稻纵卷叶螟为害期的数量预测和第三世代卵期的数量预测模型提供基础。关于数量预测模型将在下文介绍。更多还原

【Abstract】 The present paper deals with the studies of population dynamics of the 2nd generation of rice leaf roller, Cnaphalocrocis medinalis Guenee, by means of the life table method in Hailing island of Yangjiang county, Guangdong province. The life tables and average life table of 1976-1981 have been constructed. To summarize, based on the life tables and the models,the present analysis has perhaps been carries enough to show the following results.A)the plan of an integrated control of rice insect pests in Hailing island was successful. After the 4th-instar larva stage, the harmful per-iod,the population size of rice leaf roller was lower than the economic damage threshold,and the indices of population trend(I-value) of the 2nd generation were decreased to a level lower than 1, in 1976-1981, being 0.7666, 0.3088, 0.2532, 0.0040, 0.0036 and 0.1243 respectively.B)According to the component analysis of the 6 year’s average life table, the M-value showed that the natural enemies were playing an important role in controlling the population size of rice leaf rollereIn the component analysis, the M-value means that if there were no mortality coused by factor i, the index of population trend I would increase Msi times as against the original I-value.Of all mortality factors affecting the population in the 2nd generation,the "predators and other" in the period of the 1st-instar larva stage is the most imortant(MS4 = 2.46). The "predators" of egg period," predators and other" in period of 5th-instar,2nd-instar, 4th-instar, 3rd-instar larva stages are important also (Ms13 = 1.89, Ms8 = 1.87, Ms11 = 1.67, Ms8 = 1.62).The sum total of all "predators"M-valueParasites,Apanteles cypris Nixon, is an important factor also. Its sum total of M-value in the periods of the 1st-instar, 2nd-instar and 3rd-instar larvae stages is 1.89(Ms5 Ms7 Ms9 = 1.89)Theoretically, with absence of all the predators, parasites and disease agents, the I-value would have increased to 358.69 times of the original, or the population size of the 3rd generation would have been 31.78 times than that of the 2nd generation.C) According to the key-factor analysis,the data of life tables of the 1976-1981 showed that the "Predators and other"in the period of the Ist-instar larva stage is the key factor affecting the population dynamics of the insect pest in the 2nd generation.Other factors closely related to the population dynamics are "Predators and other" in the periods of the 4th-instar 5th-instar larva stages and "Parasites" in the pupa stage,These results are a basic data for constructing the model for monitoring the population size of rice leaf roller, which will be reported in following paper.更多还原