• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.295-299
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• 2007

Resistance to chestnut gall wasp (Dryocosmus kuriphilus) of Korean prevailing chestnut cultivars, new cultivars released by Korea Forest Research Institute (KFRI), and local cultivars by growers was investigated to select optimal cultivars suitable for main chestnut producing areas. During three years investigated from 2004 to 2006, we could find no damage by chestnut gall wasp in any cultivars of test sites located in Gongju and Chungju of the central area. However, most cultivars of Gwangyang, Sancheong and Hapcheon sites located in the southern area showed a lot of damage by chestnut gall wasp. Hapcheon was most severe in comparison with regional damage by chestnut gall wasp. From comparison among cultivars, Kwangeun, Sandae, Eunsan and Idae released by KFRI showed no damage suggesting the highest resistant cultivars. On the contrary, over 20% in total damage by chestnut gall wasp was investigated in Tanzawa, Riheiguri, Kurakata-amaguri, Pyeonggi, Gwangdeok, Seil, Sinipyeong and Yumabyuni suggesting susceptible cultivars. In damage by chestnut gall wasp according to investigated position within tree, weak shoot was more severe than bearing shoot. Damage by chestnut gall wasp of major cultivars in Gwangyang, Sancheong and Hapcheon sites was remarkably decreased in 2006, and it seems to be caused by biological control by natural enemies such as Torymus sinensis.

• The Korean Journal of Zoology
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• v.8 no.2
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• pp.15-18
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• 1965

Fatty acid components of the Chestnut gall wasp (Dryocosmus kuriphilus YASUMATSU) were analyzed by the method of gas chromatogrphy at various developmental stages. 1. The fatty acids identified at each stage are as follows : Larva stage : acetic acid , benzoic acid and capric acid. Prepupa stage : acetic acid, benzoic acid and capric acid. Pupa stage : acetic acid, benzoic acid and capric acid. 2. Through the development of the wasp, there were large amount of acetic acid.

• Korean Journal of Plant Resources
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• v.19 no.5
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• pp.598-601
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• 2006

In order to prevent chestnut from damaged by the chestnut gall wasp, Dryocosmus kuriphilus, a sprinkler system was installed on the chestnut orchard. Such a test was conducted at Sanchung-gun, Kyeongnam province, Korea in 2003 and 2004. Insecticide of carbaryl 50% WP, x1,500 was sprayed at every day and two-day intervals during the period of D. kuriphilus adult occurrence by sprinkler system. The chestnut gall wasps generally emerged for about 35 days from the middle June to the middle July, and peak emergence was 5 days of early July. Crown application of carbaryl by sprinkler system was found to be highly effective for control of the chestnut gall wasp. Gall formation rate of chestnut were 3.0 and 12.8% on average with crown insecticide spraying at every day and two-day intervals, while 82.9% when not treated. Control effectiveness of this insecticide spraying was 96.4% and 84.6%, respectively.

• Korean journal of applied entomology
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• v.2
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• pp.47-54
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• 1963

The chestnut gall wasp, Dryocosmus kuriphilus $Y^{ASUMATSU}$, has been recently distributed and chestnut trees have teen seriously damaged by this insects in Korea. However, this insect pest has not been investigated in Korea. This paper gives an account of field and Laboratory observations on the seasonal occurrence and the life history of the chestnut gall wasp, and the damage of the chestnut trees by. its insects. This study was carried out at Chungchungpukdo, Kangwon-do and Kyungi-do in Korea, from 1961 to 1963, inclusive. 1. The Chestnut gall wasp (Dryocosmus kuriphilus $Y^{ASUMATSU}$) has one generathion per year and females are only known. 2. The adult wasps were observed from late June to late July with peak of wasp emergence about early and middle July. Most of new adult wasps were coming out from, the galls in the morning rather than the afternoon. 3. Each wasp produced auerage 198.5 eggs and about 4.89 eggs was observed in each bud of the chestnut tree. 4, The egg period of wasps was about 30 days and they were hatching from July to August. 5. The larval period of wasps were from middle of August to middle of next June and pupation took places about early June to middle of July. 6. The adult wasps were ovipositing into the buds and from early May next year, galls were growing. They caused stunting of growth and no fruiting or dying of the chestnut tries. 7. The first observation of the wasp was made at Chaechun of Chungchung-pukdo in 1958. Up to 1963 this insects are distributed in Kangwon-do, Kyunggi-do, north part of Chungchung-pukdo and north part of Kyungsangpukdo

• Korean journal of applied entomology
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• v.31 no.2
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• pp.144-152
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• 1992

The juvenile hormone(JH) titers and juvenile hormone esterase (JHE) activities were mea¬sured in larval homogenates of the chestnut gall waL,J, Dryocosmus kuriphilus Yasumatsu, parasiting a susceptible and two resistant chestnut ( Cheuk-Pa, and Dan- Tak) varieties by GLC, Galleria wax test and Liquid scintilation counter. JH of the chestnut gall wasp was identified as JH- I. Their juvenile hormone titers were 35,800 GU/g(Cheuk-Pa), 30,900 GU/g (Dan-Tak), and 28,600 GU/g(susceptible variety). The juvenile hormone esterase activities were 1.48 n mole/min/ml(Cheuk-Pa), 1.63 n mole/min/ml(Dan- Tak), and 1.89 n mole/mini ml(susceptible variety). JH titer activity of the chestnut gall wasp parasiting resistant varie¬ties were higher than that from susceptible, whereas their JHE activity was higher in those from susceptible variety than those from resitant varieties. JH titer and JH specific esterase activity was inversely proportional.

• Journal of Korean Society of Forest Science
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• v.32 no.1
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• pp.21-28
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• 1976

This paper reports on seasonal variation of tannin, catechol tannin, pyrogallol tannin, sugar, starch and protein contained in new shoots of four races of Castanea crenata in relation to their resistance to gall-wasps. The four races were Ginyose, Shimokatsugi, Taisyo-wase and Tsuguba. 1. Tannin contents showed the lowest level during June and September, and they gradually increased afterwards. Generally tannin contents were higher in gall-wasp resistant races than in its susceptible races. Mean annual tannin contents were 0.73%, 0.845%, 0.507%, and 0.520%, respectively, in Tsuguba, Ginyose, Shimokatsugi and Taisyo-wase. 2. Catechol tannin contents did not change from February to October, however, increased after that period. Catechol tannin contents in gall-wasp resistant races (Tsuguba and Ginyose) more than doubled those in the susceptible races (Shimokatsugi and Taisyo-wase) all the year round, indicating that there may be a correlation between quantitative differences in catechol tannin and the resistance to gall-wasps. 3. Pyrogallol tannin contents were rather lower in the gall-wasp resistant races than in the susceptible races on the contrary to the above results. 4. Seasonal variation of sugar contents showed similar tendency with catechol tannin. Gall-wasp resistant races contained higher sugar contents than those susceptible races. 5. Starch contents were significantly higher during dormant period. Gall-wasp susceptible races showed higher starch contents than the resistant races did, however, this tendency varied with season. 6. There were not significant differences in protein between races but there was a tendency of higher protein in gall-wasp susceptible races. The seasonal change of protein was similar to that of starch. 7. From the above results it seems that seasonal variation of contents of tannin, catechol and pyrogallol tannin, sugar, starch and protein in new shoots of chestnut trees have some relation to their resistance to gall-wasp.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.285-290
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• 1993

This study was conducted to mvestigate the natural enemies of chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu and their seasonal prevalence of adult emergence. The natural enemies Identified were as follows: Torymus sinensis, Torymus geranii, Eutytoma Brunniventris, Eurytoma s Setlgera, Megastigmus nipponicus, Megastigmus maculipennis, Ormyrus flavrtrbwlis, Ormyrus punctiger, Eupelmus urozonus, Euplmus sp., Sycophila vanegata, and Diptem sp. Among these natural enemies of the chestnut gall wasp, Torymus sinensis, Eurytoma setigem, and Eupelmus sp. were newly recorded this time In Korea. The seasonal prevalence of parasItic wasps have been investigated in Kyonggi ProvInce. Torymus sinensis which seems to be the most dominant parasitoid emerged from withered galls formed in the previous year April to eary May. The four parasitoids such as Torymus geranii, Sycophila variegata, Eupelmus urozonus and Eupelmus sp. emerged from withered previous year galls in April to May and also from current year galls in June to August. The other parasitoids emerged from only current year galls in June to August.

• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.475-482
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• 1998

9 species of parasitoids emerged from chestnut gall samples collected at Chunchon, Kangwon in June to July 1995 - 1997, and 8 species emerged from gall samples at the 5 investigation sites in December 1997. The primary parasitoids among them were Torymus sinensis, Torymus geranii, Sycophila variegata, Megastigmus nipponicus, Megastigmus maculipennis, Eurytoma brunniventris, Ormyrus flavitibialis, Ormyrus punctiger, Eupelmus urozonus, while the secondary parasitoids were Torymus geranii, Sycophila variegata, Eupelmus urozonus, Eupelmus sp., Eurytoma setigera, Ormyrus punctiger. Torymus sp.. Some of secondary parasitoids were facultative hyperparasitoids, parasitizing the gall wasp as well as primary parasitoids, Among these natural enemies, Torymus sinensis was dominant at all sites. At Chunchon, the rate of gall formation showed decreasing tendency as the function of generation and the parasitism rate of Torymus sinensis showed increasing tendency gradually. But the rate of parasitization of the secondary parasitoids(Sycophila variegata, Eupelmus urozonus, Torymus geranii, Ormyrus puntiger) ranged from 4.0% to 10.5%. The mortality was high during June to October which was immature stage of Torymus sinensis, and mainly caused by secondary parasitoids. Torymus sinensis emerged from April to May and the estimated dates of 50% emergence was 21st April. The estimated dates of 50% emergence for the other, Sycophila variegata, Eupelmus urozonus, Torymus geranii, and Ormyrus puntiger were 25th April, 30th April, 4th May, and 22nd May, respectively.

• The Korean Journal of Zoology
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• v.13 no.1
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• pp.3-8
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• 1970

1. Paju area of Kyonggydo has received serious damages by Dryocosmus kuriphilus Yasumatsu in the bushes of Castanea crenata S. et Z. since 1965. I have also found the middle parts of whole country of Korea has damaged by this wasp. 2. Bobwonri was the worst case in its damage by Dryocosmus kuriphilus Yasumatsu with most prosperous parasite, Aletia flavostigma singularis Butler and Dictyoploca japonica Moore. I conclude that this is the result of the lack of beneficial insects and isolated bush formation. 3. The chestnut bush at Bunsuri was recovering from the damage of gall wasp nevertheless it was illustrated big damage at last year's hranches. I conclude that this recovering phenomena is closely related with the insect fauna of this area and this characteristic insect fauna was derived from the bush formation which reveals specific bush arrangement that can be illustrated as surrounded by another bush of Quercus acutissima Carruthers. 4. As a final conclusion, I recommend mixed bush formation of chestnut tree with Quercus species to control insect population dynamics in healthy status.

• Korean journal of applied entomology
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• v.38 no.2
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• pp.85-91
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• 1999

Torymus sinensis was found to be a solitary ectoparasitoid attacking the larvae ofDryocosmus kuriphilus. The sex ratio of Torymus sinensis was close to 1 : 1 in foreign chestnut varieties.Under constant temperatures of 15"C, 20$^{\circ}$C, and 25"C, the preoviposition period and longevity of theadult was longer at lower temperatures when fed on honey. Most of the Torymus sinensis female havemature eggs in their ovaries just after emergence. The number of mature eggs reached to average 22.5individuals per female in four days, which was the highest value, after the emergence and then decreasedgradually. Eggs were laid on the larvae of the host or attached on inner surface of the gall chamber. Theeggs were oval in shape, measuring 0.49 mm length and 0.13 mm width and the color of the justoviposited egg was milky white. The larvae appeared in one day after being deposited at 20$^{\circ}$C. Thepupae, 2.25 mm length for female and 1.89 mm length for male, was milky white in color just afterpupation but became black later. In Kangwon Province, development period of chestnut galls formated byDryocosmus kuriphilus were mid April to late May and its primary parasitoid, Torymus sinensis adult,emerged from withered previous year galls in early April to early May. This species has one generation ina year, and hibernated with the matured larvae. hibernated with the matured larvae.