• Journal of Korean Society of Forest Science
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• v.32 no.1
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• pp.16-20
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• 1976

Employing 7-15 resistant and 8-15 susceptible Japanese black pine (Pinus thunbergii Parl.) trees to pine gall midge (Thecodiplosis japonensis Uchida et Inouye) as samples, needle monoterpenes were analysed by GLC in January and June, and observation was made on the oviposition preference. Following results were obtained. 1. In January, the resistant trees showed higher contents of myrcene, limonene, ${\beta}$-phellandrene and terpinolene but lower contents of ${\alpha}$-and ${\beta}$-pinene and camphene compared to the susceptible trees. But in June, ${\alpha}$-pinene, camphene, limonene, ${\beta}$-phellandrene and terpinolene were higher and the content of ${\beta}$-pinene and myrcene were lower in the resistant trees than the susceptible trees. 2. The content of limonene was higher by the 6.8 percent and the content of ${\beta}$-pinene was lower by the 9.2 percent in the resistant trees than in the susceptible trees in June. 3. No preference for oviposition was found between resistant and susceptible trees. But in the resistant trees gall formation rate was quite lower than the susceptible trees. It was considered, therefore, that limonene and ${\beta}$-pinene content in the needle might be used as an indicator of the resistant Japanese black pine to the pine gall midge regardless of season.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.256-259
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• 2000

D.B.H., height, crown length, crown width, crown form, crown area, and crown volume of dead and live trees were measured and the discriminant analysis was conducted to assess individual tree risk-rating in the pine forest seriously infested by the pine needle gall midge. Thecodiplosis japonensis. Crown length, crown form, crown area, and crown volume of live tree were significantly higher than those of dead tree, while D.B.H. and tree height were not different significantly. These results represent that the trees with higher and wider crown and larger crown volume have relatively higher probability to survive from the infestation by the pine needle gall midge. Variables selected in the functions of discriminant analysis were crown area, ratio of crown length, crown form, ratio of crown volume to crown area, and ratio of crown width.

• Korean journal of applied entomology
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• v.25 no.1 s.66
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• pp.1-9
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• 1986

Periodical samplings were made in the fields, located Hwasong-Gun, Banwal-Myon, Doondai-Ri, for two years to study the major factors responsible to the population of the overwintered pine needle gall midge, Thecodiplosis japonensis Uchida et Inouye. The population densities of the overwintered larvae reduced greatly at the time of pupation and the changing patterns seemed to be influenced by environmental conditions. The estimated 50% pupation day was about two weeks earlier for the 1980 generation compared with the 1979 generation, and much higher average and the daily maximum temperatures in 1981 affected on the development of the larvae. The relative emergence rates were 14.1% for 1979 and 14.9% for 1980 generation. The relative emergence rates(Y) were affected by the moisture contents of soil ($X_1$) and its variance $(X_2),\;Y=-68.41+4.3206X_1-0.6887X_2$. The relative emergence rates seemed to be decreased with the increased variance of the moisture contents of soil. Percents of needle gall were 49.63% for 1980 and 86.87% for 1981 generation.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.138-141
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• 1982

The insecticides aldicarb$(Temik^{(R)}\;15G)$, carbofuran$(Curaterr^{(R)}\;3G)$, and disulfoton$(Disyston^{(R)}\;5G)$ were evaluated in the field for the control of the pine gall midges(Thecodiplosis joponensis Uchida et Inouye) at rate of 5 a.i.g/cm dbh using the method of circle-furrow treatment(ca. loom in furrow depth), apart 50cm Iron the trunk of the pine trees. In addition, for improving the application method of granular insecticides the effects of conventional circle-furrow treatment were compared with those of pit treatments and radical-furrow treatments. A single root-zone treatment of aldicarb and carbofuran i the pine trees was significanlty effective for the pressure of the gall incidence by the insects. Control effectiveness in three-pit treatment was identical with those in conventional circle-furrow treatment. The pit treatment compared with the circle-furrow and radical furrow treatments would be a further feasible method in saving labor cost.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.163-166
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• 1982

The pine needle gall midge, Therodiplosis japonensis Uchida et Inouye, is the most important insect pest. It requires two different habitats for the development; on trees and under the ground. The habitat specific mortality rates ere $30\~40\%,\;and\;50\~60\%$ for the respective habitats. The key developmental stage is the prepupa, and the key mortality factor is the moisture contents of the soil and its variability. Since the insect is an exotic, the population status is the periphery and in the source of infestation are considerably different. Such a difference in habitats and the population status of the insect should be considered in relation to suppression of the insect. The control strategies should be directional and rational based on the reality of the pest status. There have been substantial information on the control methods of the pine needle gall midge, and each control method has an important place, but none has always provided a satisfactory solution to the many problems associated by this insect. These methods should be applied to a system based on the ecology of the insect. There should be continued support for directed effort on the development of operational management systems for the insect: specifically, estmation of the critical economic injury level, and of the absolute density of the insect.

• Applied Biological Chemistry
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• v.23 no.3
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• pp.189-197
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• 1980

Effect of monoterpene composition in pine needles on the susceptibility to pine gall midge (Thecodiplosis japonensis Uchida et Inouye) has been pursued. The pines studied include 5 susceptible and 2 resistant species. Also included were severely damaged or unaffected P. densiflora in the pine gall midge affected region. From the needles of the pine trees, 9 monoterpenes were identified by GLC. No correlationship, was found to hold in the monoterpene composition between pine gall midge susceptible and nonsusceptible pine species. Concentrations of limonene, however, gradually increased following oviposition in the unaffected P. densiflora while the concentrations of the monoterpene remained constant in the damaged P. densiflora. Effect of high limonene concentration in the needles of P. densiflora is discussed as a possible factor inducing resistance toward the pest in the unaffected Pinus densiflora.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.609-617
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• 2000

To inverstigate the boring insects in Pinus densiflora forests, bait logs were set up in healthy-looking forests of Chunchon Hongchon and in damaged forests(gall formation rate 70----) by Thecodiplosis japonensis of Pyongchang Jeongsun. The period of investigation was from April to August in 1999. Boring insects investigated were 35 species of 12 families. Five species of them were unrecorded species from Korea. Natural enemies investigated were 5 species of 2 families. The prefered parts of tree according to species of boring insects were lower trunk in Siphalinus gigas and 3 other species, middle-stem in Monochamus sutor and 7 other species, and top stem in Orthotomicus suturalis and 1 other species. Hylurgops interstitialis were found in all parts of tree. Sap wood was attacked by Xyleborus validus Cerambycidae, heart wood by Hylobitelus haroldi Siphalinus gigas, and cambium region by Pissodes nitidus P. obscurus Shirahoshizo insidiosus Scolytidae.

• Journal of the Korean Wood Science and Technology
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• v.26 no.3
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• pp.33-40
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• 1998

The phenolic acids in needles of five pine species such as Pinus densiflora, P. thunbergii. P. virginiana. P. rigida. and P. koraiensis were analyzed seasionally (March, June, September and December) in order to investigate the resistant factors against pine gall-midge(Thecodiplosis japonensis Uchida et Inouye). The interrelation of resistance to pine gall-midge and the content of phenolic acids in pine needles was investigated in the artificial hybride pine species. The contents of salicylic acid in susceptible species (P. densiflora and P. thunbergii) to pine gall-midge which watered with salicylic acid solution in a pot was determined. The results can be concluded as follows, 1. There was a little change in total phenolic constituents of resistant and susceptible pines seasonally. The each content of benzoic acid, salicylic acid and p-hydroxybenzoic acid in June was the highest through four seasons. 2. In June, resistant species showed higher content of salicylic acid than susceptible species, while the content of gallic acid was the highest in December. 3. Among the 21 artificial hybrids(P. densiflora ${\times}$ P. virginiana. P. thunbergii ${\times}$ P. virginiana), the hybrides of the higher salicylic acid content showed the lower rate of pine gall formation. 4. Pine gall formation of the susceptible species which were watered with salicylic acid solution remarkably decreased.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.81-87
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• 1977

Resistant and susceptible pine (Pinus thunbergii, Parl) trees to pine gall midge (Thecodiplosis japonensis, Uchida et Inouye) were selected and monoterpene composition in one year old branches, shoots and needles of both groups have been analysed by GLC. The results are summarized as follows; 1. Monoterpene composition in either one year old branches or shoots were not affected by their directions (North or South). 2. Major monoterpenes in one year old branches were ${\alpha}-pinene,\;{\beta}-pinene$, myrcene, limonene, ${\beta}-phellandrene$ and terpinolene. 3. In addition to ${\alpha}-pinene$, camphene, ${\beta}-pinene$, myrcene, ${\Delta}^3-carene$, limonene, ${\beta}-phellandrene$ and terpinolene, several less volatile components which appear to be monoterpenes were also present in shoots and needles. 4. Compared with the susceptible pine, the resistant tree was found richer in limonene composition. 5. ${\beta}-Pinene$ composition in the resistant pine was less than that in the susceptible pine. 6. The difference in the composition of limonene or ${\beta}-pinene$ between two groups of pine trees was discussed in relation to the resistance to pine gall midge.

• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.593-601
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• 2009

Forest disturbances including forest fire, insect pests and diseases, landslides, and forest conversion from 1976 to 2005 were investigated to trace the changes of major forest disturbance agents and their characteristics over time in accordance with changes in natural and social environment in South Korea. While the damaged area by insect pests and diseases continuously decreased for the past 30 years, damaged areas by forest fire and landslide were fluctuating through years. The interval of large forest fires has become shorter with increased tree volume. The precipitation between January and April were significantly correlated with large fire occurrences as Pearson's correlation coefficient -0.400 (P=0.029). The composition of major insect pests and diseases damaging Korean forests has been changed continuously, and become more diversified. While damages by pine caterpillar (Dendrolimus spectabilis) and pine needle gall midge (Thecodiplosis japonensis) decreased, damage by introduced pests has been more serious recently. The change of precipitation pattern that brought more localized heavy rain or powerful typhoon resulted in the recent increase in landslide areas. The major land uses to induce forest conversion have been changed, reflecting the changes in industrial structure in South Korea as agriculture and mining in 1970s, mining and golf ranges classified in pasture in 1980s, and road and housing construction in 1990s and 2000s. Changes in forest disturbance patterns in South Korea show that a country's industrial development is jointly working with global warming on forest stand dynamics. Altering energy structure and land use pattern induced by industrial development accumulates forest volume and reforms microenvironments on forest floor, interacting with climate change, inducing shorter interval of large forest fire and changes in major species composition of forest insect pests and diseases.