|Title:||水稻瘤野螟族群發生動態與預測||Other Titles:||Population dynamics and forecasting of rice leaffolder, Cnaphalocrocis medinalis Guenee in Taiwan||Authors:||鄭清煥
|Keywords:||水稻害蟲;瘤野螟;族群動態;發生預測;rice insect pest;rice leaffolder;population dynamics;forecast of population abundance||Issue Date:||Jun-1999||Publisher:||植物保護學會||Journal Volume:||41||Journal Issue:||3||Start page/Pages:||199-213||Source:||植物保護學會會刊||Abstract:||
The rice leaffolder (Cnaphalocrocis medinalis Guenee) is one of important insect pests of rice in Asia. It can overwinter in Taiwan at very low population due to low temperature and poor host plant conditions. The number of adults catched in light trap appeared 8 population peaks annually. Two distinct maximal peaks appeared during milky to maturing stage of the first and the second rice cropping season, and the latter peak was closely correlated to the farmer one (r2=0.7616, p < 0.01). During each cropping season, the Ieaffolder could complete 3 generations. The larval population growth rate from the first to the second generation was 9.75 and 10.87 in the first and the second crop, respectively, while from the second to the third generation, it ranged from 0.20 to 0.26 in the first crop and 2.04 to 0.005 in the second crop. The earlier transplanting rice usually had lower growth rate as compared with those later transplanting ones. The larvae always injuries on top 3 leaves regardless to the stage of rice, and the peak of injuried leaves usually appeared about 14 days later than of the larval population peaks. However, the main infestation peried occurred during the heading to milky stages of rice, and the severity of infestation during this period in the second cropping season each year was observed to be closely correlated with the number of adult catched in the first and second generation of the cropping season even though the direct seeding rice, and those later planting rice and rice growing in the places sheltering from wind received much severer infestation, Based on the infestation recorded in past 12 years, the damage of this insect in the first cropping season was successively lower than the levels of economic threshold, while that of in the second cropping season was often higher. The population abundance of adult in the initial stage of the crop season was the most important factor to affect the levels of damage in main infestation period. Several equations had been developed for predicting the population abundance as well as the levels of damage of the insect in this study.
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