• The Plant Pathology Journal
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• v.39 no.2
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• pp.220-227
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• 2023

Rose crown gall caused by Agrobacterium tumefaciens is a major disease that damages the production of cutroses in Korea. The effective prevention methods for this disease include the use of resistant varieties. This study was conducted to evaluate the resistance of 58 Korean cultivars and six foreign cultivars to crown gall disease with nodal explants in vitro. Among 180 A. tumefaciens strains, pathogenic strain RC12 was selected as an inoculant strain. The strain RC12 was identified based on characteristics of some selective media, pathogenicity test, and polymerase chain reaction analysis. Forty rose cultivars formed tumors on explants inoculated with A. tumefaciens RC12. However, 24 cultivars, including 22 Korean cultivars and 2 foreign cultivars, showed resistance to A. tumefaciens RC12 without forming any tumors. Six cultivars with tumor formation rates of over 30% formed initial tumors within 23 days after inoculation. Six cultivars with low tumor formation rates of around 5% formed initial tumors after 28 days of inoculation. It was found that gall formation rate was highly correlated with the initial gall formation period. Thus, the relationship between the period of gall formation and the rate of gall formation could be useful for assessing resistance to crown gall disease. In vitro inoculation methods could be used to evaluate resistance of cut-rose cultivars to crown gall diseases.

• Journal of Forest and Environmental Science
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• v.36 no.4
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• pp.290-297
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• 2020

This study analyzed and compared the damage rate, natural parasitic rate, and the morphological characteristics of Thecodiplosis japonensis larvae, which inhabit forest areas as control areas to large urban areas in 2018 and 2019. This research was conducted to provide basic data for the management of Thecodiplosis japonensis, which harm pine needles, and the results were as follows. First, the gall formation rate of Thecodiplosis japonensis collected from urban areas was upper-crown 35.59% and 34.25%, mid-crown 25.57% and 27.95%, and lower-crown 25.34% and 26.61%; the gall formation rate of Thecodiplosis japonensis was in the order of upper-crown>mid-crown>lower-crown in 2018 and 2019, respectively. In the control areas, the gall formation rates of Thecodiplosis japonensis in mountain villages in 2018 and 2019 were upper-crown 17.72% and 21.78%, mid-crown 13.85% and 16.97%, and lower-crown 15.12% and 15.79%; thus, in the order of upper-crown>lower-crown>mid-crown. The number of larvae in the galls of needles damaged by Thecodiplosis japonensis was as follows: the average number of larvae in the pine trees of urban areas was 9 and 8 in the upper-crown, 7 and 8 in the mid-crown, and 6 and 7 in the lower-crown respectively. This shows that the number of larvae was fewer in the lower-crown than the upper-crown, and that the number of larvae was higher in 2018 than in 2019. For natural parasitic rate of Thecodiplosis japonensis, the gall formation rate and natural parasitic rate of Thecodiplosis japonensis were surveyed; the natural parasitic rate was 12.5% and 11.8% in urban areas while the rate was 21.7% and 20.9% in mountain villages in respectively in 2018 and 2019.

• Journal of Korean Society of Forest Science
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• v.61 no.1
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• pp.20-26
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• 1983

Some aspects of the change in the rate of gall formation on the red pine, Pinus densiflora Siebold et Zuccarini, by the pine needle gall midge, Thecodiplosis japonensis Uchida et Inouye, were investigated at the coastal area in Chung Nam-Do from 1977 to 1982, and were analyzed with the nationwide survey data for 2 years from 1980 to 1981. The results obtained were as follows; the gall formation rate in several areas was compared between two consecutive generations. Four regression equations were established, with X as the gall formation rate in N year and Y as that in (N+1) year: 1) Y=11.2+1.15X (r=0.833) for the stands facing north on the phase of insect population increase, 2) Y=14.3+0.82X (r=0.739) for the stands facing south on the phase of population increase, 3) Y=7.3+0.46X (r=0.478) for stands facing north on the phase of population decrease and 4) Y=11.4+0.19X (r=0.086) for stands facing south on the phase of population decrease. After invasion of the pine needle gall midge into a red pine forest, gall formation rate increased for 6 consecutive generations and then decreased to low level within a period of another 6 years.

• Journal of Ginseng Research
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• v.10 no.1
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• pp.45-54
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• 1986

These studies were carried out to obtain the basic information about transformation of ginseng plant by potential vector system, utilization of opine compound by Agrobacterium sap. , and initiation of crown gall tumor callus. Crown gall tumors were induced from stem of Panax ginseng C.A. Meyer by infection of Agrobacterium tumefaciens. Therefore, it was clarified that transformation of ginseng by Ti plasmid was possible. The crown gall tumors induced by Agrobacterium tumefaciens isolated. from the soil were different in a shape, size, and growth rate. Especially, infection of ginseng by Agrobacterium tumefaciens Y104 led to the amorphic tumor, Tumor tissue derived from stem crown gall could not be continuously cultured on the medium which did not contain phytohormone, and did not form the callus even on the medium supplemented with 2,4-D. On the other hand, the root crown gall tumors formed the calli but the formation rate of callus was quite low. As for the utilization of octopine and nopaline, it was found that 3 strains of Agrobacterium app., Y104, Y110 and C58, utilized nopaline only, Y109 utilized octopine, and Y101 failed to utilize either compound.

• Plant Disease and Agriculture
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• v.5 no.2
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• pp.90-94
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• 1999

Effect of inoculum concentration inoculation method and plant age on development of clubroot disease of Chinese cabbage seedling were examined in growth chambers. Root galls were developed at the concentration of 105 resting spore or above per ml of incoulum and as the inoculum concentration became higher rate of development of root galls was faster. In the plants with root gall development fresh weight of above ground parts was reduced to 30-44% of that of healthy plants but root weight increased by 4-10 times. Growth of diseased plants was greatly reduced as compared to healthy plants. Planting in the diseased soil as a inoculation method was most effective for disease development showing uniform infections but time of initial root gall development was delayed by root soaking inoculation. Some plants inoculated by soil drenching method did not develop root galls. However root gall enlargement after its initial formation did not differ greatly among inoculation methods. Nine-day-old seedlings showed poor development of root gall but 16-days-old seedlings was found to be most adequate for inoculation for gall development.

• 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.

• Korean Journal of Medicinal Crop Science
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• v.8 no.4
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• pp.304-311
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• 2000

This study was conducted to investigate the ratio and number of the Rhus javanica gall formed by chinese sumac aphid, Scheleechtendalia chinensis, in several different conditions in which R. javanica lives. The density of 11 to 15-year-old R. javanica was more higher and the number of galls was also higher than 1 to 5- or over 16-year-old one at these sites. The formed gall according to four directions such as the East, West, South and North was founded the highest at the East and followed South, North, and West order. The formative rate of R. javanica gall did not differ in the mixture forest, and in the habitat having a heap of a little stone and mosses near a valley was better than in the site of road perimeter. Through an index of the gall diameter and the number of chinese sumac aphid, we evaluated the gall processing and development formed by the aphid. As the density of aphids increase, the size of the gall was also more plumped. The part of phyllotaxy of R. javanica gall in leaf and pinnate of was increased in the middle and upper part of terminal leaflet and leaflet was more occupied than wing. R. javanica which did not form a gall in natural environmental, formed gall by a artificial inoculation of S. chinensis. Some gall disappeared during a gall development from various environmental conditions.

• Korean journal of applied entomology
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• v.33 no.3
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• pp.201-206
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• 1994

Trunk implantation method of phosphamidon 50% Lq.is commonly applied to control the pine needle gall midge (Thecodiplosis laponensts Uchida et Inouye) Since trunk implantaion is normally practiced during the late Spring, it is often difficult to accommodate necessay labor in mral area. As an alternative, aerial spraylng of less toxic ~nsecticide was designed. Usage of less toxic insecticide in the aenal control of pine needle gall midge can reduce the damage to forest ecosystem. The buproferin, one of the insect growth regulator, was selected at d~fferent rate of dilutions and the treatments effects ruere evaluated at different date and time When 50 t~mes diluted solution of buprofezin 40% SC was treated on different period, there was no significant difference in dficacies. the control efficacies of buproferin 40% SC was measured by occurrences (%) of gall formation of the pine needle gall midge using a ultra low volume (ULV) sprayer and the dilutions of 10X 30X and 50X of buprofez~n 40% SC gave efficacies. 72.4. 57.6 and 8.4, respectively.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.244-250
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• 1996

The objectives of this paper were to study the existence of resistant substance to pine gall midge from needles of Pinus densiflora, P. thunbergii, P. virginiana, and P. thunbergii${\times}$P. virginiana, and also to investigat whether terpenoids, fragrant substance contained in those species seduce or evade imago of pine gall midge to oviposit. Also, terpenoids and phenolic compounds were bioassayed on larva. The results are follows. Adults of pine gall midge oviposited indiscriminately all investigated pine species, while gall formation rate by pine gall midge showed 0% in Pinus virginiana, 9% in P. thunbergii${\times}$P. virginiana, 22% in P. thunbergii. It is suggested that young larvae is necrotized by resistant substance in the needles of P. virginiana. This results might mean that fragrant substance, terpenoids, extracted from pine species is not seducible or evadable substance. Larvae of pine gall midge placed on terpenoid and resin were not necrotized. The necrosis rate of larvae of pine gall midge cultivated in the solution of phenolic compounds extracted from needles of P. virginiana, salicylic acid and chitinase showed 89, 92, and 86% respectively. And necrosis rate was 56 and 59% in phenolic compounds extracted from P. densiflora and gallic acid respectively. So, it is postulated that phenolic compounds contained in needles of P. virginiana, salicylic acid and chitinase are resistant substance to pine gall midge.

• Journal of Korean Society of Forest Science
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• v.88 no.1
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• pp.31-37
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• 1999

The frequency of gall formation by pine needle gall midges ranged from 35% to 40% in both P. densiflora and P. thunbergii species. However, there was no indication of gall development from larva on both P. virgiana and P. rigida species suggesting that some specific compounds might play role in preventing gall formation of larva. The susceptible species to pine needle gall midges including P. densiflora and P. thunbergii contained a little salicylic acid under the free phenolic compound conditions while the resistant species against such insects including P. virginiana and P. rigida species contained about 37ppm to 50ppm of salicylic acid. Thus, this compound might have important roles in insect resistance. The contents of internal salicylic acid in the needles of susceptible pines increased from 9.5ppm to 20.6ppm after direct external irrigation of salicylic acid solution and flour treatment on roots. As a result, the frequency of gall formation decreased dramatically 17~19 times lower when compared with that of control. According to our results, the application of salicylic acid for effective prevention against insect damages should be performed before hatching eggs. The frequency of gall formation in the hybrid pines of P. thunbergii(susceptible) and P. virginiana(resistant) showed approximately 24% as average value of those in both species. In the case of specific individuals, it ranged from 2.8% to 11.5% in hybrids of both species. Therefore, effective production of insect resistant pines can be obtained through hybrids by crossing between susceptible and resistant species including P. thunbergii and P. virginiana by increasing internal salicylic acid contents of the needles.