我国不同地区枣疯病发生动态和主导因子分析

对我国陕西清涧、佳县 ,河南濮阳 ,山西临县、太原枣品种圃 ,安徽 ,浙江和北京等部分枣树传统分布区的枣疯病进行了典型调查研究。通过不同地区枣疯病发生历史和危害现状的比较分析 ,初步摸清了各地区枣疯病发生的不同特点和为害状况 ;发现根蘖苗繁殖方式仍是目前多数枣产区病园内苗期和幼树发病以及病害从病区传入无病区的主要原因。不同枣树品种对枣疯病的田间抗性存在明显差异 ;局部空气污染以及施肥等枣树管理措施不当会导致枣树的抗病性降低。用DAPI荧光显微镜和PCR技术检测植原体结果显示 ,病园内存在比例不等的无症带菌树 ;由此判断 ,高比例的无症带菌苗的人为传病及不利于枣树生长的环境应力是导致许多地区病害加重和爆发流行的主导因素

DYNAMIC OF JUJUBE WITCHES'BROOM DISEASE AND FACTORS OF GREAT INFLUENCE AT ECOLOGICALLY DIFFERENT REGIONS IN CHINA

A detailed investigation on jujube witches' broom disease associated with phytoplasmas was conducted at different ecological sites of jujube growing areas,including Shaanxi,Henan,Shanxi,Anhui,Zhejiang provinces and Beijing city.The historic and present circumstances of disease occurrence were surveyed,involving disease distribution,severity,transmission way,cultivation as well as geographic and environmental variation.It was found that the wide utilization of root\|spouting seedling carrying phytoplasmas had been contributing the spread of disease in a diseased orchard and from diseased areas to disease\|free ones.Several cultivars differed in resistance to the disease.Air pollution nearby the jujube orchard and improper cultivation,especially,the imbalance of fertilization,could reduce the cultivar's resistance to the phytoplasma.The phytoplasma detection by DAPI fluorescence microscopy and polymerase chain reaction (PCR) revealed that there were different proportion of symptomless infected plants (latent infection) in different infested orchards.It was assumed,therefore,that the wide use of latent infection seedlings as propagation materials and gradually deteriorating conditions for jujube growth and fruiting leaded to the prevalence of the disease in most regions.