17 松喰蟲の被害原因に就ての考察

概要

論文の詳細を見る
The writer has had opportunities to investigate pine bark beetles damage, which caused the death of pine (Pinus densiflora SIEB. ET ZUCC. and P. thunsergii PARL. and others) in Japan. In this paper the writer discusses on the cause of the pine bark beetle infestations.According to the writers investigations in the pine forests of Japan, the following factors are apparently important characteristics of the bark beetle epidemic;(1) Natural factors a) Over-mature trees b) Pure stand(2) Meteorological factors a) Damage by wind and flood b) Damage by drought c) Damage by snow(3) Human factors a) Felling operation b) Collection of resin c) Grass-cutting under pine forest d) Forest fire e) Damage dy smoke(4) Influence of fungi a) Cenangium Abietis (PERS.) REHM var. japonica P. HENN. b) Others.(5) Influence of other forest Insects a) Pine moth (Dendrolimus spectabilis BUTLER) b) Pine twig moth (Dioryctria pryeri RAGONOT) c) Pine tip moth (Evetria duplana HUBNER) d) Green pine sawfly (Neodiprion japonica MARLATT) e) Yellow pine sawfly (Neodiprion sertifera GEOFFROY) f) Others.The widespread epidimic in pine forest is the result of above mentioned circumstances offering the beetles favorable conditions for multiplication. Lack of moisture and resin in pine trees exert an unfavourable influence on the vigor of pine trees and, consequently, reduce their resistance to beetle attacks.According to the writer's observation in the pine forest of Japan, the discaloration caused by three blue stain fungi are recognized. During the summer season, the warm wet weather and high humidity favor the development of these fungi. These blue stain fungi (Ceratostomella ips RUMBOLD, Ceratostomella pini MUNCH, Coratostomella piceae MUNCH) were found associated with bark beetle infestations.
1950-03-25

17 松喰蟲の被害原因に就ての考察

スポンサーリンク

概要

著者

関連論文

スポンサーリンク