【摘要】 山桂花腐病菌为害叶片、新梢和幼果。叶片上,展叶后4～5天即可出现褐色小班,经6～7天后病斑可扩展到病叶的1/2～2/3。天气潮湿时,在病斑上生出灰白色霉层,即病菌的分生孢子。在新梢上,初生褐色至红褐色病斑,当病斑环绕新梢一周时,新梢上部萎蔫枯死。在幼果上,落花后10天左右幼果果面出现褐色病斑,逐渐扩大,直至整个果实变成暗褐色脱落。更多还原

【Abstract】 Symptoms of hawthorn(Crataegus pinnatifida Bge.)blossom blight,caused by Monilinia johnsonii(Ellis & v.)oney,were observed in or-chards.On the infected leaf one(rarely 2 or 3)spot appeared firstas a small brown dot.The pot enlarged rapidly,reaching about 1/3～1/2 of the leaf area in 6 or 7 days,and then caused leaf fall.The leafspot ommonly extended to the petiole before the infected leaf falls.Un-der humid conditions the spot was covered with the rayish-white coni-din of the fungus.On the the tops of the suckers growing at the base of large trees theleaf spot ommonly extended from the petiole to the young stem,pro-ducing stem lesions.Soon the infected stem was girlded nd wilt abovethe girlded portion.Such shoot blight was rarely on mature trees.Within 10 or more days after petal fall mall brown rotten spot oc-cured on the young fruit.After 2 or 3 days the diseased fruit was com-pletely rotted and then radually dried into a mummy followed by drop-ping of it.On the blossom no symptoms of the disease occured.更多还原