利用形态特征和基因序列分析对梨火疫病病原菌进行鉴定筛选，以期为河西灌区早酥梨火疫病诊断和制定防治策略提供科学依据。采用平板划线法，对引起河西灌区张掖市梨火疫病的病原菌进行了分离、鉴定及田间药剂筛选。结果表明，经致病性测定，分离物F2为梨火疫病病原菌。病原菌鉴定为革兰氏染色阴性，菌落呈半球形隆起，乳白色，粘性，边缘整齐，表面光滑湿润，在 28 ℃培养3 d后菌落直径3～4 mm，菌体杆状，大小为(0.9～1.8)μm×(0.6～1.5)μm，以单生为主，有时成双或3～4个连成短链状。根据培养性状、形态特征及基因序列分析，F2鉴定为解淀粉欧文氏菌(Erwinia amylovora)。田间农药筛选表明，喷药后15 d 3%噻霉酮水分散粒剂1 000倍液防效最高，为61.9%，喷药后30 d 4%春雷霉素水剂1 200倍液防效最高，为62.4%，其他各处理防效在50%以上；可见3%噻霉酮水分散粒剂1 000倍液和4%春雷霉素水剂1 200倍液2种药剂均可在生产中推广使用。

This experiment focused on isolating, identifying pathogens causing pear fire blight in the Hexi Irrigation Region and screening effective chemical treatments for field application, so as to provide a scientific basis for diagnosis and management strategies of Zaosu pears. The pathogen was isolated and identified using the plate streak method, followed by morphological characterization and genetic sequence analysis. Pathogenicity testing confirmed that isolate F2 was the causal agent of pear fire blight. The bacterium was Gram-negative, with hemispherical, convex, milky-white, and viscous colonies with smooth and moist surfaces and neat edges. After 3 days of incubation at 28 ℃, colony diameters ranged from 3 to 4 mm. Bacteria somatic was rod-shaped, measuring(0.9 to 1.8) μm × (0.6 to 1.5) μm, occurring mostly singly, occasionally in pairs or short chains of 3 to 4 bacterial cells. Based on morphological, cultural, and molecular characteristics, the pathogen was identified as Erwinia amylovora. Field efficacy trials revealed that 3% thiamphenicol water dispersible granules at 1 000× dilution exhibited the highest control efficacy of 61.9% at 15 days post-application, whereas 4% kasugamy cinaqueous solution at 1 200 × dilution demonstrated demonstrated superior efficacy of 62.4% at 30 days post-application. All other treatments maintained control efficiencies above 50%. Therefore, both thiamphenicol water dispersible granules at 1 000× dilution and 4% kasugamycin aqueous solution at 1 200× dilution are recommended for field application in pear fire blight management.

S661.2；S436.612