【摘要】 在水稻穗期分阶段设点,进行小区接虫和田间查虫分级,至收获前测定产量损失。结果表明,各生育期褐稻虱每穴虫量与产量损失率,均呈极显著的指数函数关系。在同一生育阶段,虫量越大损失也越大;在相同虫量条件下,产量损失随齐穗后天数的增加而下降。据此,求得各生育期褐稻虱虫量与损失率的综合关系式: ■=e⁽4.0893-0.1793K+0.0121K²-0.00022K³-(6.7914e^0.0624K)/x并提出在当地生产水平下的经济损害允许水平EIL=e^1.12+0.06K。进而提出中粳稻褐稻虱的防治阈限。早发年ET与EIL相交,迟发年ET恒小于EIL。更多还原

【Abstract】 In 1986,the economic injury level （EIL） and economic threshold（ET） of brown planthopper Nilaparata lugens Stal to semilate non-waxyrice were studied in different developement period since rice earingby inoculating the insects in plots or designating the plots in accord-ance with the level of natural populations.The results showed thatthere were significant exponential functional relation between the insectpopulation per hill and yield loss rates.The yield loss was increasedas the population raised in the same period,and.was decreased as thedamage period after earing was postponed under the same population.Thus,the exponential curve equation synthesizing the relations of theinsect populations and yield losses in all period and the EIL of thisinsect were developed as follows: Y=e^4.0893-0.1783K+0.0121K²-0.00022K³-(6.7914e^0.0624K)/K EIL=e^1.12+0.06K The ET were then proposed,which was similar to EIL in the yearthat the insect occurred earlier,and was lower than the latter in theyear that the insect occurred later.更多还原