留树处理期间脐橙炭疽病菌的潜伏侵染与越冬研究

为探究实施留树保鲜技术处理后脐橙炭疽病菌的潜伏侵染规律,于2010年10月至2011年2月定期采集采摘对照和留树保鲜处理脐橙植株(7～8年生纽贺尔脐橙)的果实、叶片、枝条、病残体和园内土壤,进行炭疽病菌的越冬状况调查和侵染源检测。结果显示,留树保鲜期间,炭疽病菌能在脐橙果实、叶片、枝条、病残体和园内土壤中越冬。主成分分析表明,第一因子主要由健康果实、枝条及叶片决定,可解释炭疽病菌量的73.868%,第二因子主要由健康枝条、土壤决定,贡献率为26.131%。炭疽病菌的越冬场所中,健康枝条的菌量与健康果实、叶片呈极显著负相关,与病残体、土壤呈显著负相关。综合分析认为,留树保鲜处理的脐橙炭疽病菌越冬场所以地上部位的枝条、果实、叶片为主,活病枝、健康枝是该病害的主要初侵染来源。相对于采摘对照,果实留树贮藏期间及果实采摘后,炭疽病菌均呈现增加趋势,应加强炭疽病的防治。

Latent Infection and Overwintering of Anthracnose Pathogen in Navel Orange When Keeping Fruits on Trees

This experiment collected fruits,leaves,branches,crop residues and soil of 7-8 year-old New Zealand Hal Orange periodically from the field of keeping fruits on trees and the picking control for detection from Oct 2010 to Feb 2011,and studied the overwintering conditions of Colletotrichum gloeosporioides Penz.and the sources of latent infection.The results showed that the anthracnose pathogen could be isolated from all the collected materials in the field of keeping fruits on trees.During the overwintering places,the healthy branches were significantly negatively correlated with healthy fruits,leaves,soil and crop residues.Principal component analysis showed that the 1st factor was decided by healthy branches,fruits and leaves,which accumulated 73.868% of overwintering fungi,and the 2nd factor was decided by healthy branches and soil,with contribution rate of 26.131%.Comprehensive analysis indicated that the overwintering places of anthrax fungi were mainly on branches,fruits and leaves when keeping fruits on trees,and the living diseased branches and healthy branches were the main primary infection sources.In contrast with the picking control,the anthrax fungi during stages of keeping fruits on trees and after fruits picked showed an increasing trend.Therefore,control of overwintering anthrax fungi should be strengthened.