• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.2
• /
• pp.139-143
• /
• 2001

The efficacies of several entomopathogenic nematodes of Steinernema and Heterorhabditis spp. were examined against tobacco cutworm, Spodoptera litura Fabricius. H. bacteriophora HY showed 100% mortality after 20 h against 2nd instar of tobacco cutworm. In the case of 3-4th instar, S. carpocapsae PC, H. bacteriophora HY and S. monticola CR showed 100% mortality after 47 h. In the case of 5-6th instar, S. carpocapsae PC proved more effective than the others. Generally, the number of nematodes harvested as their size decreased. Also, the highest number of nematodes was obtained in the 5-6th instar of S. litura by H. bacteriophora HY, showing about $1.3{\times}10^6$ nematodes per larva. In vitro cultured S. carpocapsae PC showed 100% mortality after 73 h against 5-6th instar tobacco cutworm, indicating that nematodes produced in vitro can be potentially used for the biological control of S. litura instead of nematodes in vivo.

• Korean journal of applied entomology
• /
• v.27 no.4
• /
• pp.185-189
• /
• 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
• /
• v.20 no.3 s.48
• /
• pp.168-172
• /
• 1981

This work was carried out to study field biology of Agrotis tekienis B. in Korea for two years (1979 and 1980), The species was found to be the dominant species among cutworms giving damage to young Plants in Spring with making up approximately $80\%$ or more of cutworms collected at Suweon and Jeonju from March to early June. During April and May which is the most critical period as far as plant damage by cutworms is concerned, those of A. tokionis larvae collected were at 5th and 6th instar. A. tokionis larvae enter a summer diapause from late May to early July and Agrotis ipsilon became the dominant species. It is also suggested that A. tokionis larvae be called as the 'dark grey cutworm', based upon its larval body color.

• Korean journal of applied entomology
• /
• v.40 no.4
• /
• pp.315-319
• /
• 2001

Damage and control of cutworms in the tobacco fields were studied during 1998~2000. It was estimated by surveys on cutworm damage that control measures should be taken for 9.0~10.2% of the surveyed fields. However, most of the interviewed growers broadcasted granule insecticides before or during tobacco plant transplantation. The damaging period and cutworm behavior suggested that the most effective control method would be the application of emulsifiable concentrate or wettable powder around the base of tobacco plants in the fields showing more than ca. 2% of damage ratio.

• Korean journal of applied entomology
• /
• v.24 no.4 s.65
• /
• pp.173-177
• /
• 1986

This study was carried out to see what makes the 'dark grey cutworm', Agrotis tokionis Butler, inflict less damage in P.E. film-mulched tobacco fields than in nonmulched ones. In field plot experiment, the damage ratio of tobacco seed lings in mulched plots(m) was reduced by 63% compared with that in non mulched ones(n). The altered environments did not affect the cutworm in mortality, which was confirmed by recovery ratio, location of larvae in soil, and developmental age. But the m/n value and damage ratio in plots of different mulching methods strongly suggest that the P.E. film itself prevent larvae from cutting the plants. Larval mortality was rapidly increased between the end of July and the end of August.

• Korean journal of applied entomology
• /
• v.31 no.4
• /
• pp.475-479
• /
• 1992

The non-steroidal ecdysone agonist RH 5849 showed almost similar LC.o values( 18.1-26.5 ppm) at all stages of larval development of the tobacco cutworm, Spodoptera litura, when treated by a leaf-disk dipping method. The feeding-inhibition rate for the 4th instar larvae was dose-dependent, and simultaneously the weight gain of 3rd instar larvae ceased within 48 hour after feeding of the cabbage leafdisk dipped into RH 5849 4.2 ppm solution. The systemic larvicidal effect of RH 5849 was compared at cabbage and tobacco whole plant test. The $LC_{50}$ values below 20 ppm(mg/kg soil) was lasted for 15 days in cabbage, 30 days in tobacco respectively.

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2000.05a
• /
• pp.123-123
• /
• 2000

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

• The Korean Journal of Pesticide Science
• /
• v.16 no.4
• /
• pp.387-390
• /
• 2012

Beet armyworm (Spodoptera exigua), diamondback moth (Plutella xylostella) and tobacco cutworm (S. litura) are insect pests causing damage in many economically important vegetables in Korea. Bacillus thuringiensis, commonly known as Bt, has been available as an alternative insecticide for many years. Five commercial Bt products and the mixtures evaluate the control efficacy against three kinds of moths. These commercial Bt products had high control efficacy against $2^{nd}$ instar of diamondback moth, but didn't show high mortality against beet armyworm and tobacco cutworm. Mixtures of Bt products didn't have synergistic effects to the tested moths. Also application of twice and four times the recommended concentration didn't improve the control effects against the tested three species of moths.

• Korean journal of applied entomology
• /
• v.47 no.4
• /
• pp.447-456
• /
• 2008

Five effective strains against tobacco cutworm, Spodoptera litura (Lepidoptera: Noctuidae), Steinernema carpocapsae (GSN1), Steinernema sp. (GSNUS-10), Steinernema sp. (GSNUS-14), Heterorhabditis bacteriophora Hamyang (HbH), and Heterorhabditis sp. (GSNUH-1) were selected among 14 isolates of Korean entomopathogenic nematode in laboratory tests. $LC_{50}$ values of above five strains against tobacco cutworm were various by different nematode strains and developmental stages of tobacco cutworm. $LC_{50}$ value of S. carpocapsae (GSN1) was the lowest by $4.0{\sim}8.3$ infective juveniles (Ijs) and 2nd instars of tobacco cutworm was most susceptible. Pathogenicity of five effective strains against tobacco cutworm depends on nematode strain, concentration, and application times. The most effective strain was determined as S. carpocapsae (GSN1). Two or three times of applications were effective regardless of nematode strain, or concentration. Efficacy of S. carpocapsae (GSN1), Steinernema (GSNUS-10), Steinernema (GSNUS-14), and Heterorhabditis (GSNUH-1) was variable depending on nematode strain, concentration, application times, and host variety. S. carpocapsae (GSN1) was the most effective and inoculation of 100,000 infective juveniles per m2 (720,000 Ijs/7.2 $m^2=1{\times}10^9$ Ijs/ha) resulted in higher efficacy. Three times of application of nematodes led to higher control efficacy than one or two applications. Efficacy of nematodes was higher on Chinese cabbage than cabbage or kale.