2020 Fiscal Year Final Research Report

Does the oak borer, Platypus quercivorus get cold resistance and make Japanese oak wilt expand to a northern high altitude place?

Research Project

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Project/Area Number	18K05735
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 40010:Forest science-related
Research Institution	Forest Research and Management Organization
Principal Investigator	Kitajima Hiroshi 国立研究開発法人森林研究・整備機構, 森林総合研究所, 主任研究員等 (70353662)
Co-Investigator(Kenkyū-buntansha)	近藤洋史国立研究開発法人森林研究・整備機構, 森林総合研究所, 主任研究員等 (10353690) 齊藤正一山形県森林研究研修センター, 森林生態保全部, 主幹 (80502583)
Project Period (FY)	2018-04-01 – 2021-03-31
Keywords	カシノナガキクイムシ / 耐寒性 / 過冷却点 / ナラ枯れ / 被害ポテンシャルマップ
Outline of Final Research Achievements	Supercooling point of Platypus quercivorus larvae from January to March were significantly lower than that in September, October, November, December, and April. This result indicates that the supercooling point is an index of cold hardiness. However, no geographical variation of the supercooling point was observed. Moreover, the minimum temperature in February in Yamagata Prefecture was not below -12°C, which is near the maximum temperature of the supercooling point. Therefore, it was thought that prediction of overwintering area of the beetle using supercooling point was not possible. On the other hand, as a result of investigating the mortality rate after overwintering at different altitudes, the larval mortality rate increased as the altitude increased. It was thought that the increase in mortality at high altitudes was due to the appearance of sub-zero temperatures before snowfall. We drew a potential map of Japanese oak wilt damage on the Oshima Peninsula, Hokkaido.
Free Research Field	森林害虫
Academic Significance and Societal Importance of the Research Achievements	カシノナガキクイムシの過冷却点は、1月から3月にかけて有意に低下することを明らかにしたことは、過冷却点による耐寒性の評価が可能であることを示した。しかし、青森から鹿児島までの個体群の過冷却点には有意な差が見らなかったことから、寒冷地への適応を議論するためにはさらに南の個体群での調査が必要であることも示した。一方、積雪前の氷点下の出現がカシノナガキクイムシの北方への分布拡大予測の要因の一つであるとの新たな知見を示した。北海道渡島半島におけるナラ枯れ被害ポテンシャルマップは、行政のナラ枯れ対策にも活用されると考えられる。