• Korean journal of applied entomology
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• v.36 no.3
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• pp.256-263
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• 1997

Supercooling points (SCP) and cold tolerance of the tobacco cutworm, Spodol~rera litura Fabricius. were measured in response to subzero temperatures. SCPs were varied among developmental stages. Eggs showed the lowest SCP (-27$^{\circ}$C). Pupae and adults had the intermediate SCP(- 18$^{\circ}$C). The SCPs (- I0 to - 16$^{\circ}$C) of larvae increased with their ages. Lethal low temperature of each stage was higher than its SCP. Preexposure of eggs and larvae to a sublethal low temperature increased their survival capacities under lethal low temperatures. The sublethal temperature also induced the fifth instar larvae to increase hemolymph osmolality and to produce cold-induced proteins of apparent molecular weights of 20 and 27 kD. These results indicate that this species is classified into a freeze-susceptible insect.

• Korean journal of applied entomology
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• v.38 no.3
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• pp.217-224
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• 1999

This study was conducted to determine the larval development of tobacco cutworm, Spdodoptera litura Fabricius, reared on leaves of different leguminous plants of 11 varieties or cultivars, and to measure amount of leaves fed by the larva. Larval duration ranged from 11.5 to 15.7 days depending on different food with the shortest on geomjeongkong-1 and the longest on daek-wangddangkong. Among 6 larval development stages, the 1st instar stages was the longest(3.2~5.0 days) while the 4th instar was the shortest (1.0~1.5 days). In general, amount of leaves consumed was increased with larval age, and consumed from 5 to 74% of total food only during the last instar stage. And female consumed more food than male. While, larval mortality and the sex-ratio seem to have no relation with the amount of food per species.

• Korean journal of applied entomology
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• v.42 no.3
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• pp.225-231
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• 2003

The susceptibility of the different larval stages of Spodoptera litura to nine insecticides was evaluated using the perilla leaf-dipping method. Median lethal concentration ($LC_{50}$) was increased with larval development in the range of 0.5 ppm to 5.6 ppm, 9.9 ppm to 27.9 ppm, 9.6 ppm to 125.1 ppm and 24.3 ppm to 546.6 ppm in the 1st, 2nd, 3rd and 4th instar, respectively. The tolerance ratio (TR), which is the TR of 90 percent lethal concentration (LC/ sub 90/) to the recommended concentration, was 0.04 to 0.8 in the 1 st, 0.2 to 7.5 in the 2nd, 0.7 to 115.3 in the 3rd and 1.2 to 485.4 in the 4th instars. Lower D$LC_{50}$ and DTR, which is the difference between the $LC_{50}$ and the TR of 4th and other instars, respectively, were observed in chlorfenapyr, chlorpyrifos and EPN while higher ones were lufenuron, chlorfluazuron and teflubenzuron. These results mean that insecticides with lower D$LC_{50}$ and DTR are effective in controlling larva of S. litura collected in Milyang, Korea.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.175-180
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• 2004

This study was conducted to determine the effect of sublethal concentrations ($LC_{10}$ and $LC_{30}$) of insecticides on pupal duration, emergence, adult longevity and oviposition of tobacco cutworm, Spodoptera litura Fabricius, when 3rd instar larva of tobacco cutworm was treated with insecticides of chlorpyrifos, ethofenprox, chlorfenapyr-bifenthrin and hexaflumuron-chlorpyrifos . Pupal duration of female and male were 6.9 days and 8.0 days at untreatment, and were 7.2 to 7.6 days and 8.3 to 8.6 days at insecticide treatment, respectively. Thus pupal duration at the insecticide treatment was slightly longer than that at the untreatment, and that of the males was slightly longer than that of the females even though significant difference between sublethal concentrations and among insecticides was not observed. Percent mergence was 88％ at untreatment and ranged from 79％ to 95％, in particular which showed above 91％ treated with chlorfenapyr-bifenthrin and ethofenprox, at insecticide treatment. Adult longevity was 7.7 days and 7.9 days for female and male at untreatment respectively, and 7.1 to 8.4 days for female and 7.7 days to 9.0 days for male at treatment. There was a significant difference between insecticides and sublethal concentrations of insecticides except showed the longest adult longevity at hexaflumuron-chlolfyrifos treatment. Total number of eggs laid were less at treatment (778-948) than that (1,010) at untreatment regardless of sublethal concentrations of insecticides. Accordingly the pupal duration and oviposition of tobacco cutworm were affected at the insecticide treatment of sublethal concentration.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.446-455
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• 2010

The characteristics of parasporal inclusion body from Bacillus thuringiensis subsp. kurstaki KB099 isolate which is high bioactive to the tobacco cutworm, Spodoptera litura, were examined. Parasporal inclusion of B. thuringiensis subsp. kurstaki KB099 isolate showed only 1 band at 130 kDa compared with B. thuringiensis subsp. kurstaki HD-l isolate producing 2 protein bands at 130 kDa and 60 kDa from by SDS-PAGE analysis without any enzyme treatment. Also, we confirmed that gut extract of sensitive S. litura KB099 isolate had digested only 60 kDa ${\delta}$-endotoxin protein. When the digestive enzyme of sensitive insect responsible for parasporal inclusion from KB099 and HD-l isolate was treated to each of them, protein band 60 KDa of KB099 was maintained up to 12 hours but all bands of HD-l were disappeared within 6 hours. In KB099 isolate, 6 genes (Cry1Aa, Cry1Ab, Cry1Ac, Cry1C, Cry1D and Cry1I) were identified by PCR analysis. Also, $Cry^-$ mutant of KB099 isolate was investigated by phase- contrast microscope, SDS-PAGE and PCR.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.333-337
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• 2006

The damage aspects of soybean by common cutworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) at different larval density and different growth stage of soybean were studied in soybean field. The percent yield reduction(Y) of soybean infested by different densities of S. litura (X, no. of larvae/plant) under outdoor conditions for a three week period were estimated by the following equations: (1) Y = 1.655X - 6.025 ($R^{2}=0.952$) for the R1 (flowering stage); (2) Y = 0.725X - 0.475 ($R^{2}=0.986$) for the R3 (beginning pod stage); and (3) Y = 0.635X - 1.325 ($R^{2}=0.986$) for the R5 (beginning seed stage). Based on the relationships between the densities of S. litura larvae and the yield index of soybean, the number of larvae (2nd-3rd instar) which caused 5% loss of yield (Tolerable injury level) was estimated to as approximately 6.7 for the R1, 7.5 for the R5, and 10.0 per plant for the R5, respectively. Average soybean leaf areas consumed by 1st, 2nd, 3rd, 4th, 5th and 6th larvae of Spodoptera litura during 24 hr at $28^{\circ}C$ was 0.3, 0.7, 2.6, 4.0, 20.1, and $55.8\;cm^{2}$, respectively.

• 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.42 no.2
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• pp.153-157
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• 2003

This experiment was conducted to investigate control effect of Spodoptera litura using nucleopolyhedrovirus in chrysanthemum seedlings of open field and plastic house. Values of LT$_{50}$ of treatment 1.0$\times$10$^{6.8}$ PIBs/ml were 6.2-5.1 days in open field and 6.9-5.4 days in plastic house. Values of LT$_{50}$ and LT$_{95}$ were shorter in open field than in plastic house. Cumulative mortality was 100% in 1.0$\times$10$^{7.8}$ PIBs/ml and also higher in open field than in plastic house. In chrysanthemum field, organic synthetic insecticide (endosulfan EC) killed S. litura larvae in 2 days after application. Motality of S. litura larva inoculated with S. litura nucleopolyhedrovirus (SINPV) 1.0$\times$10$^{6.8}$ PIBs/ml was found out from 4 days after application and maintained during 14 days. Protection values of with SINPV 1.0$\times$10$^{8}$ PIBs/ml after 16 days were 94.0% and 89.4% in open field and plastic house, respectively, and those of endosulfan 350 ppm were 91.4% and 88.6%, respectively.

• Korean journal of applied entomology
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• v.27 no.4
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• pp.185-189
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• 1988

Laboratory trials were conducted for control of onion maggot and tobacco cutworm with ento¬mogenous nematodes. The onion maggot, Delia antiqua, was exposed to Steinernema feltiae at concentration of 0,30,60, 120 or 240 nematodes per larva, and to Heterorhabditis heliot-hidis at concentration of 0, 10, 20, 40 or 80 nematodes per larva. Mortalities of the maggot ranged from 80 to 100% in S. feltiae and from 63.3 to 100% in H. heliothidis. The tobacco cutworm, SpodoPtera litura was exposed to S. feltiae at concentration of 0,50,100,200 or 400 nematodes per larva and to H. heliothidis at concentration of 0,20,40,80 or 160 nemat¬odes per larva with or without kale in petri dish. The 3rd instar larvae of the tobacco cutworm was more susceptible to both nematode species than the 4th or 5th instar at low concentration. Mortalities of the 3rd instar were 100% in S. feltiae and 67.7-100% in H. heliothidis while those of 4th and 5th instar ranged 76.7-100% and 43.3-100% in S. feltiae, and 36.7-90% and 3.3-90% in H. heliothidis, respectively. Mortalities of the tobacco cutworm larvae decreased when the nematodes were sprayed on the kale leaves in petri dish except 3rd instar.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.175-184
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• 2008

To screen highly active Bacillus thuringiensis isolates against Spodoptera litura (Lepidoptera, Noctuidae), 46 B. thuringiensis was isolated from 115 samples obtained from several crop soils. Especially, B. thuringiensis subsp. kurstaki CAB133 and CAB162 isolates showed 100% mortality against S. litura. $LD_{50}$ values of CAB 133, CAB162 and HD-1 strains of B. thuringiensis subsp. kurstaki were 0.089, 3.144 and $0.513{\mu}g/ml$ against 2nd larva of S. litura, respectively. The weight of 3rd larva of S. litura which were fed crystal inclusion protein $(1.267{\mu}g/ml)$ with B. thuringiensis subsp. kurstaki CAB133 was about 30 times lass than control group. CAB133 and CAB 162 strains of B. thuringiensis subsp. kurstaki which were taken a highly toxity against S. litura were analyzed by SDS-PAGE, and estimated the molecular weight of the Cry proteins. Their serological identification by H serotypes were showed B. thuringiensis subsp. kurstaki (3abc) type.