Microbial Control of the Tobacco Cutworm, Spodoptera litura (Fab.), Using S. litura Naclear Polyhedrosis Virus. I. The Effect of Spray on Soybean Leaves, Temperature, Storage, and Sunlight on the Pathogenicity of the Virus

곤충 핵다각체병 바이러스를 이용한 담배거세미나방의 미생물적방제. I. 기주식물, 온도, 보관 미 태양광선이 바이러스의 병원성에 미치는 영향

A nuclear polyhedrosis virus (NPV) of the tobacco cutworm, Spodoptera litura would be a promisible agent for the control of the insect. To develop a viral insecticide using S. litura NPV, effect of spray on soybean leaves, temperature, storage, an sunlight on the pathogenicity of the virus were studies as follows: Median lethal concentration ($LC_{50}$) of the virus sprayed on the leaves against the third and the fifth instar larvae were $1.301\times10^{4 PIBS}/ml$ and $1.087\times10^{5 PIBS}/ml$, respectively. On the concentration of $1.0\times10^{5 PIBS}/ml$, median lethal times ($LT_{50}$) were 7.3 days for the 3rd and 8.9 days for the 5th instar larvae. Stability of S. litura NPV was quickly decreased at the higher temperate than $60^{\circ}C$ and at the longer exposure to the higher temperature. Storage of the virus at $-20^{\circ}C$ was kept higher pathogenicity than $4^{\circ}C$ and $25^{\circ}C$. Viral activity was maintained more than 10 days in the sprayed-under leaves, but decreased at 3 day after spray in th sprayed-on the leaf surface when exposed the virus to sunlight.

담배거세미나방 핵다각체병 바이러스(Spodoptera litura nuclear polyhedroses virus: SINPV) 미생물살충제로 개발하기 위하여 기주식물, 온도 보관조건 및 태양광선에 의한 병원성 및 안정성에 대하여 조사하였다. 콩잎에 살포한 SlNPV의 담배거세미나방 3령과 5령 유충에 대한 $LC_{50}$은 각각 $1.301\times10^{4 PIBS}/ml$와 $1.087\times10^{5 PIBS}/ml$였으며 $1.0\times10^{6 PIBS}/ml$에 대한 $LC_{50}$은 3령과 5령에 대하여 각각 7.3일파 8.9일이었다. SINPV는 $60^{\circ}C$에서 4시간, $60^{\circ}C$에서 1 10분 처리하였을 때 활성이 저하되었으며 처리시간이 길어질수록 급격한 활성감소현상을 보였다. 또한 SINPV는 $-20^{\circ}C$ 동결보관이 $4^{\circ}C$나 $25^{\circ}C$ 보관보다 안정적인 활성을 유지하였다. 콩잎표변에 살포한 SINPV는 콩잎표변에 살포한 경우 3일 후에 불활화하였으나 콩잎 이면살포에서는 10일간 활성이 지속되었다.