颗粒体病毒(CnmeGV)对稻纵卷叶螟的感染及害虫种群增长的影响

The effect of Cnaphalocrocis medinalis granulovirus (CnmeGV) on larva infection and population regulation of rice leaffolder

CnmeGV是侵染稻纵卷叶螟的专性杆状病毒。本研究旨在明确田间条件下CnmeGV对稻纵卷叶螟的侵染及种群增长的影响。结果表明,在田间条件下,CnmeGV对稻纵卷叶螟具有较强的致病性,7.500×10~5OB/m^2和1.125×10~6OB/m^2田间喷洒24 d后,害虫感病显症幼虫比例达69.16%~70.77%。感染病毒幼虫威布尔频数分布拟合存活率曲线表现为死亡率是年龄的增函数,死亡主要发生在幼虫中后期的感病个体中,不同浓度致死中时间为20.16~21.98 d。种群生命表参数表明CnmeGV对稻纵卷叶螟种群具有明显的干扰控制作用,不同浓度病毒处理区的种群控制指数(IPC)为0.31~0.32。CnmeGV对稻纵卷叶螟具有致病力强,感病幼虫死亡周期长的特点,田间应用CnmeGV可以显著降低害虫种群增长趋势指数,有效抑制稻纵卷叶螟种群增长。

CnmeGV is a specialized baculovirus and can infect the larvae of rice leaffolder [Cnaphalocrocis medinalis( Guenée) ]. The purpose of this paper was to explore the effect of CnmeGV on larvae infection and population regulation of rice leaffolder in rice paddy. CnmeGV had great pathogenicity to the larvae of rice leaffolder in the field. After spraying CnmeGV for 24 days at the concentrations of 7.500× 10~5 OB/m^2 and 1.125× 10~6 OB/m^2,larva infective rates ranged from 69. 16% to 70. 77%. Survival rate curve of infected larva fitted with the model of Weibull frequency was an increasing function of mortality-age,larvae mortality mainly happened in middle and late period. Median lethal time ranged from 20. 16 d to 21. 98 d at different concentrations. Parameters from life table of natural population indicated that CnmeGV had significant interference effect on the population of rice leaffolder. Index of population control under different concentrations ranged from 0. 31 to 0. 32.CnmeGV had strong pathogenicity to the rice leaffolder,and the larvae had long death cycle. Field application of CnmeGV reduced the population trend index remarkably and restrained the population growth of rice leaffolder.