• Korean journal of applied entomology
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• v.32 no.2
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• pp.236-244
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• 1993

The development of OrientaL tobacco budworm (OTE), Heticoverpa assulta, was studied at seven constant temperatures from 18 to $33^{\circ}C$ with a 14L : 10D photoperiod on the artificial diet. The egg, larval, and pupal duration comprised ca. 10, 48, and 42% of the total developmental time (from egg to adult emergence). The lower developmental threshold temperatures for egg, larval, pupal, and overall development were 8.62, 12.65, 11.64, and $11.89^{\circ}C$, respectively. The biophysical model of Sharpe & DeMichele (1977) provided a good description of OTB's development as a function of temperature ($r^2$=0.993~O.996). The Wmbull distribution was fitted to cumulative frequency distributions of normalized developmental times for each developmental stage of OTE ($r^2$== 0.987 ~0.999).

• Korean journal of applied entomology
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• v.27 no.2
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• pp.94-102
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• 1988

Studies were carried out to describe the structure and distribution of various sensilla on the antenna and mouthparts of the Oriental tobacco bud worm (H. assulta) larvae by light and scanning electron microscopy. The larval antenna has 3 segments. The second segment has 2 hairs and 3 pegs, while the third segment shows 3 regular pegs and a segmented peg (styloconicum type). Each mandible bears 2 aporous hairs on the lateral surface. The labrum bears 12 aporous hairs on its external surface. and 6 aporous hairs, 4 coeloconica-like sensilla and 2 campaniformia-like sensilla on its epipharynx. The stipes has 3 hairs, and the galea has 3 pegs. 2 papillae and 2 domes. The maxillary palpus has only a digitiform sensillum on its 1st segment but 11 sensilla of 4 different types on its 2nd segment. Maxillary sensilla represent almost 70% of total number of larval sensilla on the mouthparts. Labial pal pus has a single segment bearing a large segmented uniporous peg and a small peg. Finally their possible fun¬ctions were suggested.

• Korean journal of applied entomology
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• v.28 no.3
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• pp.113-119
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• 1989

Larval development and adult oviposition of the Oriental tobacco budworm, Heliothis assulta were examined with tobacco leaves sprayed with aqueous or ethanolic extracts from ten selected wild plant species. High larval mortality was observed with extracts from Rhamnus davurice. Persicaria hydroPiPer, Forsythia koreana, Trifolium repens, Styrax japonica, Ginkgo bi/oba, and vilis amurensis. Most of larval mortality occurred during first and second instar, apparently due to antifeeding effects of plant extracts. These extracts also prolonged developmental period of survived larvae and increased the number of larval molts. Oviposition was not affected as much as the larval mortality, but Rhamnus davurice and Styrax jaPonica extracts reduced the number of eggs laid by more than fifty percent.

• Korean journal of applied entomology
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• v.25 no.1 s.66
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• pp.33-35
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• 1986

To discriminate features of H. assulta and H. armigera, this study was done in 1983. There is 7 spots on the forewing of H. armigera but not on that of H assulta. Ratios of length and width of valves were 5.6 on H. assulta and 4.3 on H. armigera. Numbers of setae on hindtibia of H. assulta and H. armigera were 8.5, 11.4, respectively.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.435-445
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• 2008

Due to internal feeding behavior, the oriental tobacco budworm, Helicoverpa assulta ($Guen\acute{e}e$), infesting hot pepper has been regarded to be effectively controlled by targeting egg and neonate larval stages just before entering the fruits. This study aimed to develop an efficient biological control method focusing on these susceptible stages of H. assulta. An egg parasitoid wasp, Trichogramma evanescens Westwood, was confirmed to parasitize the eggs of H. assulta. A mixture of Gram-positive soil bacterium, Bacillus thuringiensis subsp. kurstaki, and Gram-negative entomopathogenic bacterium, Xenorhabdus nematophila ANU101, could effectively kill neonate larvae of H. assulta. A sex pheromone trap monitored the occurrence of field H. assulta adults. The microbial insecticide mixture was proved to give no detrimental effects on immature development and adult survival of the wasp by both feeding and contact toxicity tests. A combined treatment of egg parasitoid and microbial pesticide was applied to hot pepper fields infested by H. assulta. The mixture treatment of both biological control agents significantly decreased the fruit damage, which was comparable to the chemical insecticide treatment, though either single biological control agent did not show any significant control efficacy. This study also provides morphological and genetic characters of T. evanescens.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.35-41
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• 2013

BACKGROUND: In organic agriculture, various cover crops have been used to control weeds. In this study, we investigated the suppressive effects of Vicia tetrasperma (L.) Schred (Eolchigi wandu) on the occurrence of major insect pests and their natural enemies in pepper. METHODS AND RESULTS: To estimate the effect of cover-crop on arthropod diversities and occurrences of insect pest in pepper. V. tetrasperma was sowed as cover-crop plot October, 2008 and 2009. Control plot was kept bare in winter season and mulched with black plastic-film before transplanting red pepper seedlings. Pepper seedlings, Capsicum annuum, were transplanted on the 19th of May, 2009 and on the 20th of May, 2010, respectively. Five Yellow sticky traps were set and changed at 7 days interval. Densities of aphids and thrips and damaged fruit rates by oriental tobacco budworm, Helicoverpa assulta, were counted. CONCLUSION(S): Populations of aphids, thrips and braconid wasps were maintained high on V. tatrasperma before transplanting pepper seedlings and in early season of pepper. However, the densities of aphids on pepper in the control plot were much higher than in the cover-crop plot in the early stage of pepper. Damaged fruit rates by both of thrips and oriental tobacco budworm were not significantly different between the two experimental plots.

• Korean journal of applied entomology
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• v.24 no.3 s.64
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• pp.141-149
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• 1985

Embryonic developmental rates of the Oriental tobacco budworm, Heliothis assulta Guenee, were compared at various constant temperatures and 16 hours of light, and detailed embryogenesis was also studied at $25^{\circ}C$. The egg was nearly globular in form and had an average equatorial diameter of 0.53mm. A single micropyle was in the center of the circular area at the anterior pole of the egg. Durations of embryogenesis at 20, 25, 30, and $35^{\circ}C$ were 147, 81, 61, and 67hrs, respectively. Embryonic death was especially higher at $35^{\circ}C$ than any other temperatures investigated. Embryogenesis progressed with changes in color and pattern, which are quite characteristic at each developmental stage of the embryo. At $25^{\circ}C$, organogenesis began in 14hrs after oviposition, formation of gut completed in 44hrs and eclosion occurred in 80hrs. The embryo formed along the long axis at early developmental stage, moved towards the equatorial plane in 24hrs, and made a half-turn on the plane in 36hrs. In 40hrs, head was oriented to the anterior pole of the egg until eclosion.

• Korean journal of applied entomology
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• v.33 no.1
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• pp.26-32
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• 1994

Electroantennography, wind tunnel observation, and field trapping experiments were carried out to investigate the biological activity of synthetic sex pheromone in the onental tobacco budworm. Heli-couerpa assulta. Two major sex pheromone components of H. assulta, Z9-16' Ald and Z11-16: Ald. elicited a big EAG response in male, but not in female Their mIXture ratios did not give much influence on EAG size Fema]e H assulta showed a great EAG response only to its host plant e extract. EAG size also increased with the amount of mixture from 001 to 10 [lg but rather decreased w when the amount was 1 00 $\mug$. H. assulta always revealed a series of stereotyped behavior in a wind tunnel. The behavioral response was different when the males were stimulated with the sex pheromone containing some minor components, 16: AId and Z9.16: Ac, or being different in mixing ratios of the two major components. The best ratio of the sex phemmone components for a attracting H assulta male adults was 20-25: 1 between Z9-16: Aid and Z11-16: Ald in net house a and red pepper field experiments in Korea When the lure contamed Z9-16: OH, attracting power rapidly decreased. The synthetic sex pheromone showed a strong attraction when compared to virgin females

• Korean journal of applied entomology
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• v.54 no.1
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• pp.7-15
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• 2015

CpBV (Cotesia plutellae bracovirus) is a polydnavirus and encodes a cystatin (CpBV-CST1) gene. Its overexpression suppresses insect immunity and alters insect developmental processes. This study aimed to construct a genetically modified (GM) tobacco to further explore the physiological function of the viral cystatin and to apply to control insect pests. To this end, the transgenic tobacco lines were screened in expression of the target gene and assessed in insecticidal activity. A recombinant vector (pBI121-CST) was prepared and used to transform a bacterium, Agrobacterium tumefasciens. The transformed bacteria were used to generate transgenic tobacco lines, which were induced to grow callus and resulted in about 92% of shoot regeneration. The regenerated plants were screened by PCR analysis to confirm the insertion of the target gene in the plant genome. In addition, the expression of the target gene was assessed in the regenerated plants by quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis showed that the transgenic line plant expressed the target gene about 17 times more than the control tobacco, indicating a stable insertion and expression of the target gene in the transgenic tobacco line. The insecticidal activity was then analyzed using the screened transgenic tobacco lines against the teneral 1st instar larvae of the oriental tobacco budworm, Helicoverpa assulta. Though there was a variation in the insecticidal efficacy among transgenic lines, T9 and T12 lines exhibited more than 95% mortality at 7 days after feeding treatment. These results suggest that CpBV-CST1 is a useful genetic resource to be used to generate GM crop against insect pests.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.737-747
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• 2017

This experiment was carried out to determine the optimal concentration of agricultural organic materials using sulfur and oil for the insect pest control in pepper and cherry tomato cultivation. The control value of aphids and Oriental tobacco budworm (OTB) was examined one day after spraying with sulfur preparation (SP) (0.33~0.17%), oil preparations (OP) (2.00~0.33%), SP+OP, OP+ginkgo leaf extracts (GLE), SP+OP+GLE on the "Super Manidaa"pepper. The aphid control in pepper was complete by applications of SP+OP (0.25+1.00%) in the early growth stage and the control value was above 98.1% by the application of OP+GLE (1.00+1.00 %), SP+OP+GLE (0.25+1.0+1%), SP+OP+GLE (0.25+1.0+0.5%) in the middle to late growth stage while showing 0% in the control treatment. The OTB was completely controlled by the 3 times application with the high concentration of SP+OP (0.25+1.00%) in pepper cultivation. This result indicates that the oil and the sulfur preparations should be applied at low concentration before insect pests do not appeared, and then sprayed at the high concentration after they appear at pepper plant. The greenhouse whitefly in 'Minichal' tomatoes was completely controlled by three times application of SP (0.25~0.33), OP (1.0~2.00%). and all the treatment of SP+OP. However, continuous control with intervals of 1~3 days was considered favorable in the tomato plant. By the periodical control with agricultural organic materials using sulfur and oil, the greenhouse whitefly, which is a high-temperature insect pest, several moths of OTB did not occur at all. In conclusion, SP+OP (0.17%+0.33%) treatment was the most economical combination to control the aphid, OTB, and greenhouse whitefly in pepper and tomato cultivation when considering operating cost. In addition, we recommend that SP should not be sprayed on the plant shoots during the day time from July to August because of high temperature.