• Korean Journal of Remote Sensing
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• v.35 no.4
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• pp.545-560
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• 2019

Unlike other critical forest diseases, pine pitch canker in Korea has shown rather mild symptoms of partial loss of crown foliage and leaf discoloration. This study used high-resolution satellite images to detect and monitor canopy decline by pine pitch canker. To enhance the subtle change of canopy reflectance in pitch canker damaged tree crowns, multi-temporal analysis was applied to two KOMPSAT multispectral images obtained in 2011 and 2015. To assure the spectral consistency between the two images, radiometric corrections of atmospheric and shadow effects were applied prior to multi-temporal analysis. The normalized difference vegetation index (NDVI) of each image and the NDVI difference (${\Delta}NDVI=NDVI_{2015}-NDVI_{2011}$) between two images were derived. All negative ΔNDVI values were initially considered any pine stands, including both pitch canker damaged trees and other trees, that showed the decrease of crown foliage from 2011 to 2015. Next, $NDVI_{2015}$ was used to exclude the canopy decline unrelated to the pitch canker damage. Field survey data were used to find the spectral characteristics of the damaged canopy and to evaluate the detection accuracy from further analysis.Although the detection accuracy as assessed by limited number of field survey on 21 sites was 71%, there were also many false alarms that were spectrally very similar to the damaged canopy. The false alarms were mostly found at the mixed stands of pine and young deciduous trees, which might invade these sites after the pine canopy had already opened by any crown damages. Using both ${\Delta}NDVI$ and $NDVI_{2015}$ could be an effective way to narrow down the potential area of the pitch canker damage in Korea.

• The Plant Pathology Journal
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• v.16 no.1
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• pp.52-54
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• 2000

Pitch canker of Pinus rigida, caused by Fusarium subglutinans f. sp. pini, was first noticed in Inchon, Korea, and is now being spread into other plantations of pines. Typical symptoms re resin flows from canders on the shoots, branches, and trunks, and resin-soaking of the sap wood under the bark. Pathogenic fungi were isolated from the infected shoots, branches, and sees on Fusarium-selective medium. Mycelial growth and microscopic characteristics were examined. Pathogenicity test was carried out by inoculating four common species of pines (P. rigida, P. densiflora, P. thunbergii, and P. koraiensis) in Korea. P. rigida and P. thunbergii showed symptoms identical to those of naturally infected trees, while P. densiflora and P. koraiensis remained free symptomless.

• The Plant Pathology Journal
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• v.26 no.4
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• pp.299-305
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• 2010

A half-sib family of two 4-year-old seedlings of Pinus $\times$ rigitaeda was inoculated with each of 20 Pinus thunbergii isolates of Fusarium circinatum (syn. Fusarium subglutinans f. sp. pini) from two pitch canker damaged sites in Jeju Island, South Korea. Initial symptoms of needle damages were visible on most of the seedlings at 18 days after inoculation. The 20 tested isolates were not significantly different in virulence, based on lesion lengths at the site of inoculation (P = 0.217). The most virulent isolate FT-7 showed the longest lesion length. Some seedlings began to die 46 days after inoculation. All seedlings were dead by 68 days after inoculation except two seedlings inoculated with each of isolates FS-2 and FS-13, respectively. Using the FT-7, 38-year-old 11 P. $\times$ rigitaeda trees, which were survived from a seed orchard severely damaged by pitch canker, were inoculated on branches in the seed orchard in Jeju Island to assess differences in susceptibility to pitch canker. The 11 trees differed significantly (P < 0.001) in susceptibility to F. circinatum based on average lesion lengths measured 56 days after inoculation. It is possible that induced resistance contributed to their capacity to limit lesion development. The susceptibility of natural selection P. $\times$ rigitaeda trees are more likely affected by interaction with F. circinatum rather than environmental conditions.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.04a
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• pp.26.1-26
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• 1999

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.402-409
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• 2005

This study was undertaken to compare and estimate the severity of pitch canker of individual trees of Pinus rigida and Pinus rigida ${\times}$ P. taeda in two seed orchards in Jeju island, in which the orchards have been damaged by the pitch canker for seven years. Wind-pollinated two-year-old seedlings of P. rigida and P. rigida ${\times}$ P. taeda, in which the seedlings of P. rigida ${\times}$ P. taeda were from seeds of phenotypically selected, uninfected(but untested) trees, were inoculated with the pathogenic fungus, Fusarium circinatum, isolated from P. rigida and P. thunbergii. The virulence of the isolates was also identified. Statistically significant difference was found in 'stem cankers'(SC; ${\chi}^2=7.76$, P=0.05) among 4 plantations of P. rigida ${\times}$ P. taeda of two seed orchards. P. rigida was higher in 'top kill' (TK) and 'branch tip symptoms' (BT) than those of P. rigida ${\times}$ P. taeda. In artificial inoculation tests, mortality of the seedlings from the resistant candidates was 14% higher than that of the seedlings from the susceptible candidates. This result may becaused by unknown pollen trees and/or candidate tree selection based only on phenotype. Two of five fungal isolates, C-6-L(9) and C-6-L(19), showed significantly higher mortality (68% and 60%, respectively) than others, suggesting that these isolates can be used as virulent isolates for a mass artificial inoculation. Resistance candidate seedlings that were selected from this study can be utilized as useful materials for fundamental studies of genetics and biochemistry to breed resistance varieties to pitch canker.

• Landscaping Tree
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• s.106
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• pp.23-24
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• 2008

최근 소나무류에서 많이 발생되고 있는 푸사리움가지마름병은 외국의 경우 pitch canker(수지궤양병)라 불리며, 그 유래는 가지, 순, 노출된 뿌리에 발생한 궤양에서 많은 양의 수지가 흘러나오는데서 이름 지어 졌다. 우리나라에서는 1995년도 도입된 리기다소나무에서 이 병이 발견되었으며, 점차 그 피해가 증가하고 있는 실정이다. 푸사리움가지마름병은 미국의 남동부지역 플로리다에서 1946년에 처음 보고되었으며, 조림지, 종자원 묘포장에서 만성적으로 발생되고 있는 병으로 1976년 이후 이병은 지역적인 질병에서 국가적이고 범세계적인 중요 질병으로 발달하였다.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.165-169
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• 2010

Fusarium circinatum is the causal agent of the pine disease commonly referred to as pitch canker. In this study, F. circinatum was isolated from the diseased Pinus rigida in the golf courses, Korea. The morphological characteristics and the molecular features of the isolates were investigated to identify the pathogen. Histone H3 gene and IGS rDNA region was analyzed and consequently the isolates identified as F. circinatum. All of them have the same sequences and the mating type was determined as MAT1-1. The inhibitory effect of the methanol extracts from the disease resistant pine species, Pinus koraiensis and Pinus densiflora and a susceptible species, P. rigida were evaluated against the isolate, F. circinatum. As a result, the extracts of P. koraiensis and P. densiflora showed higher antifungal activity than that of the susceptible, P. rigida.

• The Plant Pathology Journal
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• v.26 no.4
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• pp.394-401
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• 2010

Resin flow, symptom development, and lignin biosynthesis in response to wounding and fungal inoculation were investigated in Pinus rigida and Pinus densiflora. The two-year-old seedling stems were subjected to three types of treatments: (i) wounding without inoculation, (ii) wound-inoculation with a conidial suspension of Fusarium circinatum, and (iii) pre-wounding woundinoculation with the fungus 20 days after the initial wounding. Resin flow from wounding sites was more evident in P. rigida than P. densiflora in all treatments. The wound-inoculation with the fungus induced almost two-fold higher levels of resin flow than the other treatments in both species. The pre-wounding woundinoculation appeared to result in a decrease in pitch canker development in the two pine species. Some reductions in disease severity were observed in the prewounding wound-inoculated P. rigida, showing a mean disease severity of less than 85%, compared with approximately 100% in the wound-inoculated stems. Disease severity was approximately 50% in the woundinoculated P. densiflora, whereas 10% in the pre-wounding wound-inoculated stems. Higher amounts of lignin were found from bark (ca. 40%) than from xylem (ca. 30%). The wound-inoculated bark and the pre-wounding wound-inoculated bark exhibited higher amounts of lignin among the other treatments. These results suggest that the wound-inoculation apparently prompt the increase in resin flow and lignin biosynthesis from the two pine species, and the prior wounding may be involved in decreased disease severity against the further invasion of F. circinatum.

• Research in Plant Disease
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• v.17 no.2
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• pp.177-183
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• 2011

Four-year-old seedlings of Pinus thunbergii, Pinus densiflora and Pinus rigida were inoculated with Fusarium circinatum isolate (FT-7), the pitch canker fungus, from P. thunbergii, to evaluate the effects of the pathogen on disease development and gas exchange rate. Needle dehydration was evident on 2 of 10 seedlings of P. thunbergii and P. rigida at 18 and 21 days after inoculation, respectively, while no symptoms were observed in P. densiflora seedlings throughout the experiment. Gas exchange stopped completely in 4 of 5 measured seedlings of P. thunbergii and 2 of 5 measured seedlings of P. rigida at 25 days after inoculation, and in the remaining 3 seedlings of P. rigida at 39 days after inoculation. Disease development in P. thunbergii seedlings was faster than that in P. rigida seedlings. By the time, the experiment was ended at 78 days after inoculation, 9 of 10 seedlings of P. rigida and 8 of 10 seedlings of P. thunbergii seedlings treated with FT-7 was almost dead, but all seedlings of P. densiflora were still healthy. We suggest that P. densiflora is resistant to F. circinatum in the current study, and gas exchange rate of the species after inoculation does not differ significantly compared to that of untreated control.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.112-117
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• 2008

Pre-infection behavior of Fusarium circinatum on stems of pine species was investigated with scanning electron microscopy. Two-year-old stems of Pinus densiflora and p. rigida were inoculated with the fungal conidial suspension and subjected to $25^{\circ}C$ for up to 16 hr. Most microconidia germinated 12 hr after inoculation on pine stems. Conidia produced germ tubes from either one or both ends of microconidia. Germ tubes grew over the stem surface and appeared to enter host tissues through natural openings on pine stems. Surface cracks in the cork were entrance sites of germ tubes of F. circinatum. In addition, host cell wall cracks were often found at the tip of germ tubes. The cuticle appeared to be eroded either at the tip of germ tubes or around germlings. Germ tubes also produced appressoria-like structures, exhibiting swollen tips of germ tubes on the stem surface. There seems to be no significant differences in the pre-infection behavior of F. circinatum on stems between the two pine species.