• Korean journal of applied entomology
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• v.28 no.2
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• pp.82-87
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• 1989

Mass production of Spodoptera litura nuclear polyhedrosis virus (SINPV) was carried out on massively reared host insects. The yield of SINPV was maximal with $6.7{\;}\times{\;}10^9$ PIBs per larva on the 8th day post inoculation, when 5th instar larvae were inoculated with $1.1{\;}{\times}{\;}10^7$ PIBs per ml, and 2 g of artificial diet was sufficient for food consumption of a larva. The moribund larvae were more suitable for handling and mass production of virus than the completely dead larvae. The larvae, when treated with methoprene ($Manta^{\circledR}$), prolonged their larval period and consequently became bigger to result in higher yield(about 15%) of virus.

• Korean journal of applied entomology
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• v.27 no.4
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• pp.219-224
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• 1988

Rearing of Spodoptera litura fed on arfificial diet basically formulated with kindby bean powder was much promisible for production of S. litura nuclear polyhedrosis virus(SINPV) than that on kidney bean leaves. The $LC_{50}$ of SINPV against 3rd and 5th instar were $4.48{\times}10^{3}$ PIB/ml and $4.52{\times}10^{4}$ PIB/ml, respectively. The $LC_{50}${/TEX} of SINPV varied from 5.8 days to 7.7 days at higher inocula in the testes. The larval growth of 1st and 3rd instar larvae fed on virus were much delayed and the larval were killed within 4th instar in the former and within 5th instar in latter. S. litura larvae were very susceptible to multinucleocapsid nuclear polyhedsosis virus (MNPV) of Autographa californica, S. littoralis and Trichoplusia ni.

• Microbiology and Biotechnology Letters
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• v.21 no.6
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• pp.513-519
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• 1993

The alkaline protease in the polyhedra preparation of Spodoptera litura nuclear polyhedrosis virus was successfully inactivated by heating at 100C for 20 minutes. SDS-PAGE analysis indicated that heat inactivated polyhedra is composed of major proteins of 31kDa and presumptive its polymer protein of 62kDa. However, this polyhedra was converted into several smaller molecular weight proteins when treated with midgut juice, but not by treatment with heat-inactivated midgut juice.

• Korean journal of applied entomology
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• v.30 no.2
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• pp.144-149
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• 1991

Biochemical characteristics of Spodoptera uigua nuclear polyhedrosis virus (SeNPV) isolated in Jinju were studied. SeNPV contained a number of nucleocapsids within a viral envelope embeded in polyhedra. The polyhedral protein of SeNPV was composed of a single polypeptide with a M. W. of 30kd. Double-immunodiffusion test showed that the polyhedral protein of SeNPV had common antigenic determinants with SINPV and BmNPV. Virion proteins of SeNPV were resolved into 49 polypeptides by silver staining after SDS-PAGE. The approximate genome size of SeNPV by restriction endonuclease analysis was 1l0kb.

• Korean journal of applied entomology
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• v.29 no.4
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• pp.252-256
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• 1990

Viral insecticides were formulated with Spodoptera litura nuclear polyhedrosis virus and different U.V. protectants based on white carbon, molasses, and white carbon and molasses mixture to use as microbial control agents. Effect of rainfall on the attachment of formulated viruses to leaves was no different between the treated and the non-treated experiment. Persistence of the formulations was lated 5 days on the surface-sprayed leaves and 12 days on the under-sprayed leaves which was showing 60% mortality. Total mortality of the viral insecticides was more than 97% with no differences among them. Field evaluation of three viral insecticides in soybean field was very successful then carried out in Chinju, a southern part of Korea. Mortality by the formulation in the field during 14 days was more than 93%, but the formulations contained molasses showed phytotoxicity on soybean leaves. Spray effect of the viral insecticides was begun to appear from 7 days later than that of chemical insecticide.

• Korean journal of applied entomology
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• v.27 no.4
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• pp.211-218
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• 1988

Polyhedral proteins and the endogenous alkaline protease associated with larval-derived polyhedra of nuclear viruses isolated from Spodoptera litura, Bombyx mori, and Hyphantria cunea were investigated. Polyhedral proteins prepared under alkaline protease heat-inactivated condition were separated as one band with 31Kd in S. litura a H. cunea NpV and 30Kd in B. mori NPV by the SDS-polyacrylamide gel electroptoresis. Whereas polyhedral proteins without heat-inactivation were degraded into smaller polypeptides with a certain pattern in alkaline solution. The results of double-immunodiffusion and western blot analysis with antisera against polyhedral proteins indicated that those three polyhedral proteins had common antigenic determinants and the degradation of polyhedral proteins by alkaline protease could be confirmed.

• Korean journal of applied entomology
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• v.29 no.3
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• pp.184-189
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• 1990

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.

• Korean journal of applied entomology
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• v.40 no.2
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• pp.137-141
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• 2001

This experiment was conducted to investigate the control effect of nuclear polyhedrosis virus and NeemAzal-T/S on Spodoptera litura larvae. In laboratory test, values of$ LT_{50}$ and $LT_{95}$ when treated with S. litura nuclear polyhedrosis virus (SINPV) $1$\times$10^{8}$ PIBs/ml plus NeemAzal-T/S 200 ppm were 1.94 and 8.33 days, respectively. Control effect of the combination of SINPV $1$\times$10^{8}$ plus NeemAzal-T/S 200 ppm was higher than the other concentrations. This mixed treatment could reduce LT$_{95}$ by 3 days. When SINPV alone was sprayed to the S. litura larvae reared on chinese cabbage seedling, the mortalities were 10.7~6.7% at 4 days after treatment. In combinations of SINPV plus NeemAzal-T/S at each level of concentration, the mortalities appeared faster and higher at 4 days after application than single treatment. Especially, the mortalities by combinations of SINPV $1$\times$10^{8}$ /PIBs/ml plus NeemAzal-T/S at 75~200 ppm were 100% at 9 days after treatment. The body weight of untreated larvae was increased 9.4-folds from 235 mg to 2194 mg after 7 days. However, the increasing levels of larval weight were 4.8- and 7.0-folds in the separate treatments of NeemAzal-T/S and SINPV, respectively. Whereas in the combinations of SINPV $10^{4~8}$ PIBs/ml plus NeemAzal-T/S 75~200 ppm, larval weight was increased 3.9 to 2.9-folds. These results showed that the mortality and inhibition of larval weight in the combination of SINPV and NeemAzal-T/S were highly enforced by synergistic effect.

• Korean journal of applied entomology
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• v.29 no.4
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• pp.244-251
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• 1990

Three viral insecticides were differently formulated with a nuclear polyhedrosis virus isolated from Spdodoptera litura by addition of feeding attractant, anti-precipitate of polyhedra, spreading agent, and UV-protectants. Sucrose was effective for attraction of larval feeding to increase the mortality and for protection of polyhedra from inactivation by sunlight when added 1% to 5% of sucrose solution to the formulations. Contents of additives to the formulations were 0.5% in polyvinyl alcohol to prohibit the precipitation of polyhedra and 0.1% in Triton X-100 to spread and wet the formulations to the plant. Inactivation of the virus under sunlight was decreased when added 800g of white carbon to 100 L of water in the white carbon formulation and 30% of molasses to the molasses's. In the formulation of white carbon and molasses mixtures, activation of the virus was increased when mixtured 500g of the former with 10% of the latter. Three formulations were persisted their pathogenicity more than 95% of mortality at 3 days p.i. Encapsulation of the polyhedral surface was more distinctively coated with the carbon and showed more effective in the residual effects of the white carbon than others, but the molasses more attractive for larval feeding.