新疆部分地区苹果、核桃和杨树腐烂病的病原鉴定

 树木腐烂病在新疆主林果种植区均有不同程度的发生,近年呈加重趋势。本研究在调查了新疆阿克苏、和田、伊犁、喀什和库尔勒等地区苹果树、核桃树和杨树3种林果腐烂病田间发病情况的基础上,重点对14个样本点的样品进行病原物的分离与鉴定。结果表明,各样本点3种林果均有不同程度的腐烂病发生,分离鉴定结果为引起苹果树腐烂病病原菌主要为Valsa mali var. mali(分离频率为64.5%),其次是V. mali var. pyri(25.8%)、V. malicola(3.2%)和V. nivea(6.5%);引起核桃树和杨树腐烂病病原菌为V. sordida(分离频率为83.3%和96%)和V. nivea(分离频率为16.7%和4%)。离体枝条及苹果果实上的致病性测定结果表明,3种林果上分离得到的病原菌均能感染原寄主。引起新疆部分地区苹果树腐烂病的主要病原菌是Valsa mali var. mali,核桃树和杨树腐烂病的主要病原菌是V. sordida。同时,基于实际生产中存在感病枯死杨树枝干作为苹果园、核桃园树体支撑木的现象,推测3种林果腐烂病菌间可能存在交叉感染的潜在风险。

Identification of causal agent of apple,walnut and poplar Valsa canker disease in partial areas of Xinjiang

Tree canker disease is quite common on forest and fruit trees in Xinjiang and has been becoming more serious in recent years. We investigated Valsa disease on apple, walnut and poplar trees in Aksu, Khotan, Ili, Kashgar and Korla, which occurred to a certain degree, and collected the diseased samples from 14 locations for pathogen isolation. The results showed that the main pathogens identified on apple tree samples were Valsa mali var. mali (isolation frequency was 64.5%), V. mali var. pyri (25.8%), V. malicola (3.2%) and V. nivea (6.5%). The V. sordida (83.3% and 96%) and V. nivea (16.7% and 4%) were obtained from walnut and poplar tree samples, respectively. In pathogenicity test on detached branches and fruits, all strains could infect their corresponding original host plant. In conclusion, Valsa mali var. mali is the main pathogen caused Valsa canker on apple, while V. sordida is the major one caused Valsa canker on walnut and poplar in partial areas of Xinjiang. Meanwhile, we speculate a potential risk of cross infection among these three kinds of trees because the diseased poplar branches are used as support wood in orchard.