• Korean journal of applied entomology
• /
• v.29 no.4
• /
• pp.277-285
• /
• 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
• /
• v.29 no.4
• /
• pp.286-293
• /
• 1990

Studies were carried out to investigate the change in protiens and carbohydrates from diapausing pupae of the Oriental tobacco budworm, Heliothis assulta Guenee. The oxygen consumption rate of non-diapausing pupae through the whole pupal period showed an U-shaped curve, while that of diapausing pupae decreased to a mean level of 20$\mu$1/g/hr. But the rate of oxygen consumption increased in diapausing pupae before their emergence. The body weight of diapausing pupae showed almost no change during 12 days after pupation. The total contents of major carbohydrates and soluble proteins were higher in diapausing pupae than those in non-diapausing pupae and the change in carbohydrate and protein contents was more dynamic in non-diapausing pupae than that of diapausing pupae. the electrophoretic band patterns of proteins were similar in both of diapausing and non-diapausing pupae. Diapausing pupae increased their haemolmph osmolarity further when they were exposed to low temperatures.

• Korean journal of applied entomology
• /
• v.26 no.3 s.72
• /
• pp.145-150
• /
• 1987

Carborhydrate contents were compared between diapausing and non-diapausing pupae of the fall webworm, Hyphantria cunea DRURY. Glycogen content in the whole body of diapausing pupae kept at $-5{\pm}1^{\circ}C$ was less than that of those left at room temperature, while the amounts of trehalose and sorbitol showed the reverse trend. The osmotic pressure of haemolymph was higher in diapausing pupae than that in non-diapausing pupae. The mean oxygen consumption rate of diapausing pupae was $4{\sim}6.7$ times less than that of non-diapausing, normal pupae.

• Korean journal of applied entomology
• /
• v.27 no.1
• /
• pp.6-13
• /
• 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
• /
• v.32 no.2
• /
• pp.139-150
• /
• 1993

This study was conducted to investigate the effect of 20-hydroxyecdysone on diapausing pupae of Hyphantna cunea. Treatment of 20-HE at the dosage of 5 $\mu$ g or higher/g live weight terminated diapause in about 50% of Hyphantna cunea pupae treated, and some malformed adult emerged at dosages of 10 or 12.5 $\mu$g of 20-hydroxyecdysone/g live wt. The maximum concentration of 20-hydroxyecdysone in the whole body of normally developing pupae was about 3.2 $\mu$g/g on the 6th day after pupation, and in that of diapausing pupae treated with 20 -HE about 4.1 $\mu$g/g on the 6th day after the treatment. But diapausing pupae showed a low level( 1.7 $\mu$g/g) of maximum 20-HE concentration. In diapausing pupae treated with 20- HE, glycongen content was lower than in normally developing pupae, but the changing pattern was similar to that observed in normally developing pupae. Glucose(and/or sorbitol) and trehalose content of 20-HE-injected pupae reached the maximum value on the 6th day after the injection, which were higher than those of normally developing pupae. The amount of soluble haemolymph proteins was lower but the total soluble protein content of haemolymph-rernoved whole body was higher in 20-HE-injected pupae than that in normally developing pupae.

• Korean journal of applied entomology
• /
• v.26 no.3 s.72
• /
• pp.139-144
• /
• 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
• /
• v.23 no.1 s.58
• /
• pp.42-48
• /
• 1984

The developments of overwintering larvae of the peach fruit moth, Carposina niponensis Walsingham, were studied in Suweon. Among fully grown larvae leaving from apple fruit, the earliest diapause larva was observed late July, about $50\%-diapause$ in middle August and $100\%-diapause$ in early September. Induction of the diapause seemed to have relationships with the time of oviposition: the incidents of the diapause started with the larvae grown from the eggs which had been laid in late June or late July depending on the prevailing weather condition. The termination of the diapause seemed to be in early December, and almost all of the larvae incubated after January were pupated. For the breakage of the diapause, it required chilling period more than one month, and the most effective temperature seemed to be $5\~10^{\circ}C$, while the temperature lower than $0^{\circ}C$ seemed to be inhibitory, if not at all. The overwintered larvae started to pupate in middle May, and the developments of the over-wintered larvae were affected by the temperature as well as the moisture contents of soil in the spring. The dry condition of soil increased the mortality of the developing larvae.

• Korean journal of applied entomology
• /
• v.30 no.4
• /
• pp.258-264
• /
• 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 Tobacco Science Conference
• /
• 1998.05a
• /
• pp.29-29
• /
• 1998

• Korean journal of applied entomology
• /
• v.54 no.4
• /
• pp.383-392
• /
• 2015

We investigated the induction of pupal diapause and number of generation for H. armigera using outdoor rearing and sex pheromone trapping in Suwon, Korea. Over-wintering pupae were induced when neonate larvae were reared in the outdoors from late Aug. to early Oct. in 2013 and 2014. H. armigera adults emerged from late May to early Jun. for 2013 colonies and from late May to late Jun. for 2014 colonies. The colonies placed after mid September produced only diapause pupae, to show environmental conditions that day-lengths on the rearing start date were 11 h 49 min~12 h 24 min, and mean temperatures before pupation were $14.8{\sim}20.7^{\circ}C$. Summer diapause was not observed in all colonies. The peak occurrence of H. armigera adults from sex pheromone trap in Suwon and Hwaseong were pooled and showed four generations (1st: from late Apr. to mid Jun., 2nd: from mid Jun. to late Jul., 3rd: from mid Jul. to late Aug., 4th: from late Aug. to mid Oct.). A degree-day model for development of H. armigera developed by Mironidis and Savopoulou-Soultani (2008) was used to validate the number of generation from field observations using pheromone traps. The 3rd and over-wintering generations were mainly overlapped. It was decided that H. armigera has one over-wintering and three complete generations in a year, and diapause is induced from offsprings of the 3rd and 4th generations adults. It is expected that larvae of the 1st and 2nd generations give a damage to ear zone in maize fields in which have been planted during April.