• International Journal of Industrial Entomology and Biomaterials
• /
• v.31 no.2
• /
• pp.103-106
• /
• 2015

The oriental tobacco budworm, Helicoverpa assulta (Lepidoptera: Noctuidae), is classified as a quarantine pest that must be controlled for the exportation of Korean paprika to the USA. We performed a confirmatory test of gamma irradiation against the last-instar larvae and pupae of H. assulta in paprika. Previous, small-scale gamma irradiation at a dose of 100 Gy to the last-instar larvae allowed emergence of adults, though they were abnormal, but 200 Gy prevented adult emergence completely. For pupae, irradiation of 5- to 6-day-old pupae with 300 Gy prevented normal emergence completely. To gather confirmatory data applicable to phytosanitary quarantine regulations, larvae and pupae were placed inside paprika in a box and were irradiated with 200 Gy and 300 Gy, respectively. After irradiation with 200 Gy (measured doses 170-199 Gy) of 2,186 individuals of the last-instar larvae, 10.84% survived, but either formed abnormal pupae (7.57%) or died during the pupal stage (3.27%), resulting in no emergence of normal adults. For pupae, the dose of 300 Gy (measured doses 276-319 Gy) given to 1,200 pupae allowed 10.75% to survive and 9.17% to emerge with deformity. However, 1.58% of irradiated pupae emerged normally, requiring an increased dose for complete prevention of normal emergence. Subsequently, an increased dose of 400 Gy (measured doses 340-402 Gy) to 1,005 pupae allowed 88.35% to emerge, but all emerged with deformity. Thus, irradiation treatment with a minimum dose of 400 Gy will provide quarantine security for all premature H. assulta in exported paprika.

• Journal of the Korean Society of Tobacco Science
• /
• v.18 no.1
• /
• pp.12-20
• /
• 1996

The spermatogenesis and chromosome number were investigated in the pupal testes of Helicouerpa assulta Guenee by light microscopy. During the spermatogenesis, each bundle of P8(256) sperms developed by 6 mitotic and 2 meiotic spermatogonial divisions. From the early stage of spermatogenesis, it was distinguishable between two kinds of sperm differentiation, eupyrene and apyrene spermatogenesis, which are characteristic in Lepidoptera, by the differences in nuclear shape and cell distribution in immature spermatocyst. Through the followed spermiogenesis, the spermatocysts were developed into two kinds of mature cyst, a streamline-shaped eupyrene cyst with nucleated sperms of thready head or a long spindle-shaped apyrene cyst with anucleated sperms of cylindrical head. As the results off chromosomal analysis at metaphase of the spermatogonial mitosis and spermatocytic meiosis, the chromosome number were 2n=6a/n=31, respectively, and no variation between individuals.

• Journal of the Korean Society of Tobacco Science
• /
• v.20 no.1
• /
• pp.71-79
• /
• 1998

Haemolyph carboxylesterases induced in diapausing pupae of Helicoverpa assulta Guenee were investigated. Increase in the activity of the electrophoresed isozyme bands were observed during the diapausing pupae. The isozymatic composition exhibited remarkable alterations represented as disappearance and induction of some isozyme bandsp which were identified as carboxylesterase (CE) on the basis of their specificities to inhibitors. Much higher activity of the induced CE was shown in reaction with $\beta$-naphthyl acetate ($\beta$-Na) than $\alpha$-naphthyl butyrate ($\alpha$-Nb), representing the high regioselectivity to $\beta$-naphthyl group. Optimal temperature for the enzyme activity was different to the substrates used 37$^{\circ}C$ in $\beta$-Na and 4$0^{\circ}C$ in $\alpha$-Nb, respectively. However, the optimal pH for the enzyme activity was the same as 7.5 regardless of the substrates used, and relatively high thermostability of the CE was demonstrated by showing the denaturation at high temperature (50~55$^{\circ}C$).

• The Zoological Society Korea : Newsletter
• /
• v.12 no.2
• /
• pp.87.1-87
• /
• 1995

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
• /
• 1995.10b
• /
• pp.213.1-213
• /
• 1995

No Abstract, See Full Text

• Journal of the Korean Society of Tobacco Science
• /
• v.18 no.1
• /
• pp.39-48
• /
• 1996

A storage protein(SP-2) was confirmed in haemolymph during larval-pupal-adult development of tobacco burdworm(Helicoverpa assulta Guenee), and its biochemical characteristics were investigated. The titer of SP-2 showed a peak at mature larva, decreased gradually through the late pupal stage, and became undetectable at adult period. As the results from electrophoretic mnysis, SP-2 was confirmed to be glycolipoprotein(M.W. 332kDa) relatively stable to heat( $\leq$ 68$^{\circ}C$ ). This storage protein was determined to be a tetramer composed of a single subunit with MW of 83kDa, and the isoelectric point was 5.7. The amino acid composition of the SP-2 was characterized. It has relatively high content of methionine and histidine, whereas the contents of tyrosine and phenylalanine were relatively low.

• Korean journal of applied entomology
• /
• v.33 no.1
• /
• pp.6-11
• /
• 1994

The Spatial distribution pattems of the oriental tobacco budworm (OTB), Helicoverpa assuita, eggs w were studied in red pepper and tobacco fields. With a plant as a sample Unit. Taylor's power law analyses indicated that om egg spatial patterns were clumped in red pepper fields (a=1.3914, b = 1.1648) and were unifom in tobacco fields (a = 1.6035, b = 0.6880). In red peppers om eggs w were found in leaves (76.2%), fruits (16.8%), stems (6.5%), and flowers (0.4%). The upper leaf surface ( (70.1 %) contained sianificantly more eggs than the lower surface (25.2%). In tobaccos most eggs were also found in leaves. However, the lower surface (66.3%) contained significantly more eggs t th

• Proceedings of the Korean Society of Sericultural Science Conference
• /
• 2001.04a
• /
• pp.70-70
• /
• 2001

• Proceedings of the Zoological Society Korea Conference
• /
• 2003.08a
• /
• pp.160.1-160
• /
• 2003

No Abstract, See Full Text

• Korean journal of applied entomology
• /
• v.49 no.4
• /
• pp.393-400
• /
• 2010

The parasitism, development time, hatchability, and progeny production of Trichogramma chilonis(TC) females developed in eggs of Helicoverpa assulta (HAs), Cadra cautella (CC), and Helicoverpa armigera (HAr), respectively, were compared with those developed in reciprocal eggs at constant temperatures of $25{\pm}2^{\circ}C$ and relative humidity of 50~70% under 16L-8D. Developmental performances of TC reared in each of the three hosts on the following hosts(host tested) appeared differently, and were affected most by the size of the proceeding hosts and test host. Among the parameters parasitism and progeny production were affected more than others. Parasitism was significantly different between the treatments, lowest in CC-HAr($10.1{\pm}2.05%$) and highest in HAr-HAs($47.0{\pm}2.09%$), and the hatchability showed similar pattern. Development time as well was shortest in the CC-HAr where previous host is smallest and test host is biggest. The highest number of progeny production of TC was observed in HAr-HAs($93.9{\pm}6.87$ wasps), and the lowest was CC-HAs($18.4{\pm}6.36$ wasps).