• 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.35 no.3
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• pp.205-208
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• 1996

Psylla pyricola population from Suwon($37^{\circ}$16' N) begins to enter diapause by exposure to a photoperiod of 14hr light. Over 93% of adults were induced to enter diapause when exposed to 13hr loght period, and at 18 and $25^{\circ}C$, the critical photoperiod was not influenced. When the photoperiod was switched during the nymphal stage from 16L to 10L, no morph change was occurred in the 4th and 5th instars. Average number of eggs laid per female was 486.2 in winter form adult and 387.2 in summer form adults, and average oviposition periods were 34 and 24 days, respectively.

• Korean journal of applied entomology
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• v.49 no.2
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• pp.115-121
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• 2010

The bean bug, Riptortus clavatus Thunberg (Hemiptera: Alydidae), is a pest of soybeans and tree fruits. It enters reproductive diapause during winter. We studied the effect of different combinations of temperature, day length, and treatment period on the termination of diapause in R. clavatus using adult females collected in October and November 2006. Ovarian development was used to determine diapause termination. The treatments were: (1) HTLD; $25^{\circ}C$, 14L:10D treatment for 1, 2, 3 weeks and 30 days, (2) HTSD; $25^{\circ}C$, 10L:14D treatment for 1, 2, and 3 weeks, (3) LTLD; $8^{\circ}C$, 14L:10D treatment for 1, 2, and 3 weeks followed by HTLD for 3 weeks, and (4) LTSD; $8^{\circ}C$, 10L:14D treatment for 1, 2, and 3 weeks followed by HTLD for 3 weeks. The HTSD treatments did not affect ovarian development, and resulted in no significant difference in the number of mature eggs in ovaries or the percentage of diapause-terminated females compared to the control females before treatment. The percentage of females that terminated diapause was significantly higher in the HTLD treatment than in the HTSD treatment. The HTLD treatment for more than 14 days increased the percentage of diapause-terminated females, accelerated the development of the ovaries, and increased the number of mature eggs in ovaries. Compared with the HTLD or HTSD treatments, the LTLD or LTSD treatments followed by the HTLD treatment accelerated ovarian development and increased the number of ovipositing females. The pre-LTSD treatment for 1 week was enough to increase the number of eggs oviposited.

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

• Korean journal of applied entomology
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• v.44 no.2
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• pp.91-95
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• 2005

This study was conducted to investigate the morphological characteristics, overwintering sites and behavior for each stage of Oligota kashmirica benefica (Coleoptera: Sthphylinidae). Egg was oval type, yellow, 0.3 mm size. Larva exuviated 3 times and the last (3rd) instar, length 1.6 mm, wide 0.4 mm, became dermata pupa in soil. Adult was lightish dark-brown, and coriaceous forewing covered a half of abdomen. O. kashmirica benefca mainly overwinters with adult at Japanese cedar (Cryptomeria japonica) windbreaks of orchards, but it did not diapause in greenhouse during winter.

• 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.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.409-422
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• 2022

Two dominant thrips in hot pepper (Capsicum annuum) cultivating in greenhouses are Frankliniella occidentalis and F. intonsa in Korea. This study investigated their overwintering physiology. These two thrips were freeze-susceptible and suppressed the body freezing temperature by lowering supercooling point (SCP) down to -15~-27℃. However, these SCPs varied among species and developmental stages. SCPs of F. occidentalis were -25.7±0.5℃ for adults, -17.2±0.3℃ for pupae, and -15.0±0.4℃ for larvae. SCPs of F. intonsa were -24.0±1.0℃ for adults, -27.0±0.5℃ for pupae, -17.2±0.8℃ for larvae. Cold injuries of both species occurred at low temperature treatments above SCPs. Thrips mortality increased as the treatment temperature decreased and its exposure period increased. F. occidentalis exhibited higher cold tolerance than F. intonsa. In both species, adults were more cold-tolerant than larvae. Two thrips species exhibited a rapid cold hardening because a pre-exposure to 0℃ for 2 h significantly enhanced the cold tolerance to a lethal cold temperature treatment at -10℃ for 2 h. In addition, a sequential exposure of the thrips to decreasing temperatures made them to be acclimated to low temperatures. To investigate the overwintering sites of the two species, winter monitoring of the thrips was performed at the greenhouses. During winter season (November~February), adults of the two species were not captured in outside of the greenhouses. However, F. occidentalis adults were captured to the traps and observed in weeds within the greenhouses. F. occidentalis adults were also emerged from soil samples obtained from the greenhouses during the winter season. F. intonsa adults did not come out from the soil samples at November and December, but emerged from the soil samples obtained after January. To determine the adult emergence due to diapause development, two thrips species were reared under different photoperiods. Adult development occurred in all photoperiod treatments in F. occidentalis, but did not in F. intonsa especially under short periods. Tomato spotted wilt virus, which is transmitted by these two species, was detected in the weeds infested by the thrips during the winter season. These results suggest that F. occidentalis develops on weeds in the greenhouses while F. intonsa undergoes a diapause in the soil during winter.

• Korean journal of applied entomology
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• v.32 no.2
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• pp.139-150
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• 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
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• v.36 no.1
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• pp.30-36
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• 1997

Except for a cosmopolitan and major pest of apples, Tetranychus urticae Koch, Tetranychus mites in Korea such as T. viennensis Zaher, T. kanzawai Kishida, and T. truncams Ehara have been considered as quarantine pests by Canada and United States. Even though these mites are not feeders on apples, they are suspected to attach accidentally on apple h i t s in autumn as females enter the diapause. The characters used to identify Tetranychus mites have been confined to the shape of aedeagus in adult male. To develope a fast and accurate alternative identification protocol applied to hibernating female mites on apples, their mitochondrial DNA (mtDNA) were examined to find out any polymorphisms to discriminate each species from the other ones. Three pairs of primers for polymerase chain reaction (PCR) were used to amplify cytochrome oxidase subunit I (CO-I) coding region in mitochondrial DNA5 of four species of Tetranycus mites. The longest amplified product was estimated its size as about 680 bp. Digestion with restriction enzymes, AluI, Ddel, and Sau3A, showed length polymorphisms, which will he useful as diagnostic markers to identify Tetranychus mites. Schematic restriction maps in amplified region were shown for each species.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.469-477
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• 2012

Ostrinia larvae feed the pods and stem of red bean and seriously damage the bean production from farmers. In this study we investigated biological and developmental characteristics including field collection, host feeding preference, artificial rearing diet, morphological and molecular taxonomical identification, and pheromone analysis for an Ostrinia sp. in Korea. The male adults have massive tibia in the middle legs and 3-lobed uncus in the genitalia. The partial nucleotide sequences of mitochondrial cytochrome oxidase I (COI) and II (COII) were not corresponded to those DNA sequences from other Ostrinia species reported previously in Japan and China. Host plants for this species are also different from the previous species reported. In the gas chromatography (GC) analyses, (Z)-9-tetradecenyl acetate was not detected from the pheromone gland of our species while the component as a sex pheromone was found in O. zaguliaevi and O. zealis, With taken results, we conclude this Ostrinia species in Korea is Ostrinia scapulalis or closely related species. When larvae collected in a fall were incubated in the outdoor condition, they emerged to adult between June and July in the next year. The result indicates that the winter diapause could be started in late larval stage. In addition, we developed a semi-synthetic artificial diet adopted for mass rearing of the O. scapulalis in laboratory.