Distribution of Bursaphelenchus xylophilus in Naturally Infected Pinus densiflora and P. koraiensis and Migration of B. xylophilus in Artificially Inoculated P. densiflora Seedlings

Research in Plant Disease 2012;18(2):101-108.
Published online June 30, 2012.

보문 : 자연감염된 소나무와 잣나무 내 소나무재선충 분포 및 인공접종한 소나무 묘목 내에서의 소나무재선충 이동

김재근 ( Jae Geun Kim ) , 김병관 ( Byung Kwan Kim ) , 이승규 ( Seung Kyu Lee ) , 김진철 ( Jin Cheol Kim ) , 한상섭 ( Sang Sub Han ) , 차병진 ( Byeong Jin Cha )

Distribution of Bursaphelenchus xylophilus in Naturally Infected Pinus densiflora and P. koraiensis and Migration of B. xylophilus in Artificially Inoculated P. densiflora Seedlings

Jaegeun Kim, Byungkwan Kim1, Seung-Kyu Lee2, Jin-Cheol Kim3, Sangsub Han4 and Byeongjin Cha5*

Kang's Tree Hospital, Seoul 138-050, Korea
¹Dong-Gang Tree Hospital, Youngwol 230-800, Korea
²Division of Forest Insect Pests and Diseases, Korea Forest Research Institute, Seoul 130-712, Korea
³Ecofriendly New Materials Research Group, Daejeon 305-600, Korea
⁴Department of Forest Environmental Science, Chonbuk National University, Jeonju 561-756, Korea
⁵Department of Plant Medicine, Chungbuk National University, Cheongju 361-763, Korea

Received: May 21, 2012 Revised: June 14, 2012 Accepted: June 19, 2012

Abstract

In 2006, pinewood nematode, Bursaphelenchus xylophilus, was isolated from about 50 years old trees of Pinus densiflora and P. koraiensis showing leaf-wilt and -drying symptoms in Gwangju, Gyeonggi-do and Chuncheon, Gangwon-do. Isolation of pinewood nematodes from sapwood of infected pine trees showed no difference in population density between tree species and among the sampling heights on the main stem. Migration of pinewood nematodes in the host tree were investigated by inoculation of red pine (P. densiflora, 3 years old) seedlings with B. xylophilus. The nematodes seemed to move in red pine seedlings prior to multiplication and it might have taken about 20 days to start multiplication and expression of symptoms including wilt and dieback. In initial time after inoculation, nematodes started migration through the cortical resin canal from inoculated site and further showed upward and downward movements. More nematodes were observed in cortical resin canal during early period of inoculation and later in resin canal of xylem and tracheid also while, the pith still remained free from nematode. The density of B. xylophilus was higher in seedlings of low-vigor with poor root growth than in seedlings of normal root growth. Seedlings showing high density of B. xylophilus exhibited stem discoloration and secondary infection by fungus at the inoculation site.

Key Words: Pinewood nematodes, Red pine, Resin canal, Wilt