Competition among three entomopathogenic viruses in larvae of the smaller tea tortrix, Adoxophyes sp.

在筑波的茶田中的Adxophyes sp.的幼虫种群的病毒性疾病的流行进行了测定。从死亡的幼虫中分离到三种昆虫病原病毒，即核型多角体病毒（NPV）、昆虫痘病毒（EPV）和颗粒体病毒（GV）。EPV是最常见的病毒，并负责23.1%的死亡，在蜱虫幼虫。在实验室条件下，研究了NPV与EPV或GV在小型茶毛虫幼虫体内的竞争。用核型多角体病毒（NPV）感染家蚕四龄幼虫，第5天开始产生子代病毒眼状体。EPV感染四龄幼虫后，第10天开始产生子代病毒隐体。而用NPV和EPV同时感染小菜蛾四龄幼虫时，均未产生EPV的病毒包合体，说明NPV在三种昆虫病原病毒中的竞争能力最强。三种病毒之间竞争能力的差异似乎源于这些病毒的内在自然增长率的值的差异。

The prevalence of viral diseases in a larval population of Adxophyes sp. in a tea field in Tsukuba was determined. Three entomopathogenic viruses, a nucleopolyhedrovirus (NPV), an entomopoxvirus (EPV) and a granulosis virus (GV) were isolated from the dead larvae. The EPV was the most common virus and was responsible for 23.1% of the deaths in the Adoxophyes sp. larvae . More than 25% of larvae were infected with two or more of the viruses simultaneously.Competitions between NPV and EPV or GV in larvae of the smaller tea tortrix, Adoxophyes sp. were investigated under a laboratory condition. When the fourth instar larvae of Adoxophyes sp, were infected with NPV,progeny viral oculusion bodies began to produce at day 5 post infection. When the fourth instar larvae of Adoxophyes sp. were infected with EPV,progeny viral occulusion bodies began to produce at day 10 post infection. However, no viral occlusion bodies of EPV were produced when the fourth instar larvae of Adoxophyes sp, were simultaneously infected with NPV and EPV.These data suggested that NPV had the most competitive ability among three entomopathogenic viruses. Difference in competitive ability among three viruses seems to originate from difference in values of the intrinsic rate of natural increase of these viruses.