• Korean journal of applied entomology
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• v.29 no.4
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• pp.277-285
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• 1990

Laboratory and field studies were conducted to investigate the initiation and termination factors for pupal diapause in the Oriental tabacco budworm, Heliothis assulta Guenee. Diapause induction was dependent of photoperiod and temperature experienced by 4th and 5th instar larve. One hundred percent of pupal diapause was obtained when larvae were grown at 10L/14D or shorter and $20^{\circ}C$. But at $25^{\circ}C$ the maximum rate of diapause was only about 85% at 8L/16D, the shortest photoperiod tested in this experiment. Adults, eggs or pupae did not respond to diapause-inducing environmental conditions. The critical photoperiod was 12-12.5 hr at $25^{\circ}C$and 14-14.5 hr at $20^{\circ}C$. In the field-collected sample 100% of diapuse rate was observed on Sept. 20 and thereafter in Suwon and middle part of Korea. Cold temperature treatment was not necessary in the termination of pupal diapause, but accelerated adult development.

• Korean journal of applied entomology
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• v.26 no.3 s.72
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• pp.139-144
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• 1987

This study was carried out to investigate the incidence and termination of pupal diapause in the fall webworm, Hyphantria cunea Drury. Larvae obtained from overwintered pupae were reared on Morus alba leaves at $25{\pm}1^{\circ}C$ with the relative humidity of 60% or higher in a laboratory. The critical photoperiod for pupal diapause initiation is between 14hrs and 14hrs & 30 minutes at $25{\pm}10^{\circ}C$. The developmental period of larvae was shorter under longer photoperiod at $25{\pm}1^{\circ}C$. In nature. diapause termination seems to begin in late December. The diapausing pupae did not emerge at all when they were transferred to a favorable environment before the time.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.287-294
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• 1995

Studies were carried out to elucidate the efficacy of exogeneous 20-hydroxyecdysone treatment on terminating pupal diapause in the fall webworm. Hyphantria cunea Drury. And the difference was also investigated between normal adult development and post-diapause development after 20-hydroxyecdysone treatment. In the diapause termination rate of pupae treated with 20-hydroxyecdysone after storage for various periods at 16L:8D and $25\pm$$1^{\circ}C$, at the highest rate was observed from the group stored for the longest period and the lowest rate from those stored for 1.5 months. The time needed for adult emergence was inversely proportional to the chilling (at $0\pm$$1^{\circ}C$) period, and the longer its exposure period at low temperature, the higher its sensitivity to 20-hydroxyecdysone treatment. Pupal diapause duration was almost the same, regardless of storage period in the total darkness or at the photoperiod of 16L:8D, and also they successfully emerged to adult even without any experience at low temperature. The oxygen consumption rate in normally developing pupae showed nearly a typical U-form. But, that of diapausing pupae treated with 20-hydroxyecdysone slowly increased and jumped 14 days after the treatment. Pupal diapause began before formation of adult tissues, an a timing of adult tissue formation coincided with ascending timing of the metabolic rate in both normally developing pupae and diapausing pupae treated with 20-hydroxyecdysone. The diapausing pupae treated with 20-hydroxyecdysone was similar to normally developing pupae in band patterns of proteins from haemolymph or fat body.

• Korean journal of applied entomology
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• v.27 no.1
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• pp.6-13
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• 1988

Studies were carried out to investigate the diapause-sensitive stage, the effect of 20-hydroxye- cdysone on diapausing pupae and the changes in pupal proteins of the fitll webworm, HYPha¬ntria cunea Drury. The stage sensitive to diapause-inducing photoperiod lies between 5th and 15th day of the larval development. And the oxygen consumption rate of diapausebound pupae decreased to a mean level of $30mu$l $O_{2}$/g/hr. The 20-hydroxyecdysone was effective in raising the respiratory acivity of 2.5% homogenate of the diapausing fall webworm pupae and in causing a normal adult development of the diapause-bound pupae. The soluble protein content rapidly declined in normally-developing pupae, but in diapause-bound pupae it was more or less static with much higher quantity. And protein bands separated from fat body of diapause¬bound pupae were different from those of nondiapausing pupae.

• Korean journal of applied entomology
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• v.29 no.4
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• pp.230-237
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• 1990

Studies were carried out to examine seasonal occurrence and emergence pattern of the onion fly, Delia antiqua (Meigen), in the field of Chinju city in Gyeongnam province from 1984 to 1987. Trap catch revealed that the onion fly had three generations in a year, the second flight being partial; the peaks of adult occurrence were at mid April for the overwintered generation (1st flight), at early June for the first generation (2nd flight), and at the period from late September to early October for the autumn generation (3rd flight). It was shown that parts of the pupae in the first and almost all of the pupae in the second (or autumn) generation underwent summer diapause. The pupal periods were less than 22.4 days for the non-diapaused pupae, while those of the diapause. The pupal periods were less than 22.4 days for the non-diapaused pupae, while those of the diapaused pupae were form 8.5 to 145 days in the first generation in he filed, being shorter for the pupae pupated later. This resutled in synchronization on the emergence of these diapaused pupae at late September, with the adults from the second generation pupae. The ratio of diapausing pupae increased among the later pupated ones in the first generation ; the pupae which had been pupated in early May included 43.8% of diapausing pupae, while more than 86.7% of the pupae were under diapausing state for the pupae pupated in late May and thereafter. More than 93.3% of the pupae went into diapause, regardless of pupation time for the second generation.

• Korean journal of applied entomology
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• v.30 no.4
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• pp.258-264
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• 1991

Studies were carried out to investigate effects of temperature and photoperiod on diapause induction and of juvenile hormone III and 20-hydroxyecdysone treatment on diapausing adults of the alder leaf beetle, Agelastica coerulea Baly(Chrγsomelidae: Coleoptera). Its life cycle and ovarian development in adults were also observed. The beetle had one year life cycle with egg, larval, pupal and adult periods being 7-10, 19-21, 14-15 days and about 10 months, r respectively. All adults showed a diapause syndrome when the larvae were reared at $20^{\circ}C$ or $25^{\circ}C$ in combination of photoperiods of 16L/8D, 12L/12D, or 8L/16D. Their ovarioles did not s show any development of vitellogenesis before or during diapause and even when exposed at $15^{\circ}C$ after overwintering. When diapausing adults were treated with JH III they resumed feeding and laid several eggs and broke diapause condition temporally. But diapausing adults treated with 20-hydroxyecdysone did not show any response.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.04a
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• pp.49-49
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• 2003

DOPA decarboxylase (DDC), which converts DOPA to dopamine, is important for many biological event such as cuticular melanization, sclerotization and neurotransmission in insects. Recently, it has been also shown that DDC activity is correlated with pupal diapause in M. brassicae. The silkworm, Bombyx mori is a typical insect diapausing at early embryonic stage. (omitted)

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.201-209
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• 2004

Overwintering ecology of the peach pyralid moth, Dichocrosis punctiferalis Guenee (Lepidoptera: Pyralidae) was studied in laboratory and in a chestnut orchard in 2001/2002 winter and 2003 spring. All twenty-four female and fourteen male moths were fruit-feeding type which were emerged from the larvae collected at the same chestnut orchard in 2003 winter. Periodical thermal treatment of overwintering larvae at $25^{\circ}C$ revealed that diapause termination of the larval population started from the end of January and was completed until April 20 in southern region of Korea. Pupation of diapause-terminated larvae started from early May and reached to $100\%$ at June 3 in chestnut orchard. Days to pupation of female larvae after diapause termination were 12.5, 8.9, and 7.5 at $20^{\circ}C,\;25^{\circ}C$, and $30^{\circ}C$, respectively. Those of male larvae were similar to those of females. Pupal periods of female were 14.7, 11.8, and 9.0 days at the three temperatures. Moths of the overwintered generation emerged from May 20 to June 28, and reached to $50\%$ emergence on June 8 to 9 under emergence cage. Attraction of the male moths of overwintered generation to sex pheromone traps showed that the date of $50\%$ catches to the traps were June 17, when data from 3 southern regions of Korea were pooled.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.449-462
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• 2021

We analyzed the effects of temperature on the survival, development, and reproduction of the non-diapause Asian corn borer, Ostrinia furnacalis (Lepidoptera: Crambidae). A 16:8 h light:dark photoperiod was supplied to the non-diapause stages of O. furnacalis. The insects were raised on an artificial diet at seven constant temperatures between 15 and 35℃ for immature stages, and eight temperatures between 13 and 33℃ for the adult stage. The survival rate of eggs exceeded 70% at all temperatures, whereas survival of larvae was as low as 7.4% at 15℃. The developmental periods of the immature stages decreased with increasing temperature, but the larval period did not decrease further at 35℃. The pupal weight increased with increasing temperature, but the female weight decreased at 35℃. Variations with different last larval instars within the colonies at different temperatures were observed. Adults produced offspring at all tested temperatures. Adult longevity and the pre-oviposition and oviposition periods decreased with increasing temperature, but the pre-oviposition period increased at 33℃. Total fecundity exceeded 400 viable eggs at 22℃ and 31℃. The mean daily fecundity during the oviposition period and the mean daily fecundity on the day of oviposition increased with increasing temperature, but decreased at 33℃. Daily fecundity sharply increased at earlier adult ages and slowly decreased thereafter. The simulated oviposition frequency was greatest at 22℃. The lower developmental threshold temperatures were estimated to be the lowest at 9.7℃ for the first instar larva and the highest at 14.7℃ for the 5th to last instar larval stage, using a linear model.

• Korean journal of applied entomology
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• v.25 no.1 s.66
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• pp.11-16
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• 1986

Local difference in post-overwinter developmental periods was investigated by incubating the overwintered larvae collected from 8 locations at $25^{\circ}C$ begining January 15 and February 15. Based on the 2nd incubation test, it was found that Chunseong colony had the shortest pre pupal period of 17.9 days, while Gwangsan colony had the longest 27.7 days. In general, prepupal period showed negative correlation with latitudes. Average pupal periods were not significantly different among colonies. Adult emergence period showed the same trend as prepupal periods. Chunseong and Pyeongtaeg colonies emerged faster than the other colonies and showed a single peak of adult emergence, while Nonsan, Iri, Gwangsan colony showed several peaks of adult emergence.