【作者】 郭世保；

【导师】 杨家荣；

【作者基本信息】 西北农林科技大学 ， 植物病理， 2005， 硕士

【摘要】 苹果黑星病是由Venturia　inaequalis　引起的重要真菌病害之一,世界各苹果产区均有发生。它主要危害叶片和果实,造成叶片早期脱落,果实产量和品质降低,同时对于该病的防治也增加了成本投入。苹果黑星病在我国为检疫性病害,但已在我国许多地区发生,严重威胁着我国的苹果生产。　通过调查明确了陕西省苹果黑星病的病情分布。陕西省绝大部分地区有苹果黑星病发生,且西部地区发生较重。其中秦岭北麓区病叶率为10.67‰,显著高于其它四个地区,发病最重。渭北高塬西部病叶率为7.57‰,病情较重,关中平原西部病叶率为6.13‰,病情较轻,但二者差异不显著,关中平原东部病叶率为2.13‰,发病轻,渭北高塬区东部病叶率为0.17‰,发病极轻,且该地区只是局部零星分布。不同品种间发病率存在差异,病叶率依次为嘎啦>富士>红星>秦冠。生产上主栽品种富士和嘎啦均为感病品种。　对渭北3 个果园苹果黑星病进行了系统调查,依据落叶上和芽鳞内外分生孢子数量和存活率、果园内捕捉到孢子的类型和数量、病叶率的时间动态等试验结果,并结合对洛川、白水、长武、永寿、泾川、平凉等地苹果黑星病的普查结果,初步确定子囊孢子是渭北旱塬苹果黑星病的初侵来染,分生孢子不能越冬。　对苹果黑星病潜育期及其病原菌产孢量研究结果表明,苹果黑星病在嘎啦、富士、秦冠3 个品种上的潜育期分别11.1 天、13.2 天、15.7 天;温度对潜育期有很大影响,日平均温度为18℃时,最适宜发病;病菌在3 个品种叶片上的产孢量存在显著差异,其产孢量分别为2.8263×10~4、7.4168×10~3 和1.1465×10~3 孢子/mm~2。从陕西省苹果产区十二个县(市)共分离出18 个菌株,并通过人工接种测定了它们在秦冠、富士、嘎啦、红星和乔纳金五个品种上致病性。结果表明,陕西苹果黑星病菌不同菌株致病力有显著差异。根据它们在以上5 个品种上反应型和平均严重度的测定结果,将其分为强致病力菌株:PD2、GB1、NC3、YC4,中等强度致病力菌株:LC1、PA7、JYC1、FD6、XYB2、　PB3、XD4、SC4、XC8、NB8 和弱致病力菌株:HC3、XYD5、JYA6、CD7,并分别制定出不同级别的反应型和平均严重度的标准参数更多还原

【Abstract】 Apple scab, caused by an Ascomyccete fungus, Venturia inaequalis, was regarded as one of the most important disease of apple and was found in practically all apple-growing regions throughout the world. It mainly damaged leaf and fruit and could result in defoliation and poor fruit value, and the extra cost for controlling was included also. Even though apple scab was the internal quarantine disease, it was expanded to most apple growing areas in Shaanxi province. Distribution of this disease in main apple-growing regions of Shaanxi was found by field investigation, which showed that apple scab existed throughout the Guanzhong plain and north part of apple growing areas. The percentage of diseased leaf in the north of QingLin Mountains was round 10.67‰, which was the heaviest, and it reached significant difference from those of other four areas. The west Weibei plateau and the west Guanzhong plain were 7.57‰and 6.13‰respectively and there was no significant difference of that between them. The east Guanzhong plain and East Weibei plateau regions were 2.13‰and 0.17‰respectively. The percentage of diseased leaf made great difference among the different cultivars, which was Gala>Fuji>Red Star>Qinguan. The cultivars of Fuji and Gala, most popularized in Shaanxi Province, were susceptible to apple scab. According to the conidia and its percentage of germination of Venturia inaequalis in/outer buds, the type and the number of the trapped spores and the temporal dynamic of the percentage of diseased leaf in 3 different orchards in north of Weibei and combined with extensive investigation in Luochuan, Baishui, Changwu, Rongshou, Jinchuan, Pingliang et al., the result indicated that the resource of the first infection came from ascospore of V. inaequalsi and conidia didn’t overwinter in those areas. Incubation period of apple scab and the number of sporulation of Venturia inaequalis were studied. Results indicated that the incubation period of Gala, Fuji and Qinguan were 11.1, 13.2 and 15.7 days respectively. Temperature had great effect on incubation period. The incubation period of apple scab was the shortest at 18℃of per-day average temperature. The number of Sporulation on leaves of Gala, Fuji and Qinguan were 2.8263×104, 7.4168×103, 1.1465×103 conidia /mm2 respectively, which showed significant difference(a= 0.05). 18 isolates collected from 12 counties or cities were inoculated and the pathogenicity was determined on cultivars of Qinguan, Fuji, Gala, Red Star and Jonagold, which the pathogenicity showed significant difference among those isolates. According to the infect type and average severity, 18 isolates were classified into strong pathogenecity type, including PD2, GB1, NC3, YC4, moderate, including LC1, PA7, JYC1, FD6, XYB2, PB3, XD4, SC4, XC8, NB8 and weak, including HC3, XYD5, JYA6, CD7. The standard parameter of infection type and severity were determined respectively.更多还原