【作者】 董宝成；

【导师】 黄云；

【作者基本信息】 四川农业大学 ， 植物病理学， 2004， 硕士

【摘要】 鱼腥草(Houttuynia cordata Thunb)属三白草科，蕺菜属，多年生草本植物。鱼腥草是一种中药、保健和美食兼用的野生和栽培植物。 鱼腥草紫斑病(Nigrospora sp．)是四川省雅安市“三九”药业鱼腥草种植基地一种新的病害，其病株率100％，病叶率58％，危害严重，已成为该基地鱼腥草的主要病害。该病不仅影响鱼腥草的生长和造成产量损失，而且严重影响采收后鱼腥草的深加工(如生产鱼腥草针剂)，降低鱼腥草的品质。本文是鱼腥草紫斑病(purple spot of heartleaf houttuynia)这一新病害较为系统的研究结果，详细记载描述了鱼腥草紫斑病的症状特点和病原鉴定，研究了鱼腥草紫斑病菌的生物学特性、病害循环以及对防治该病害的药剂进行筛选和田间防治。结果如下： 1．鱼腥草紫斑病症状 鱼腥草紫斑病主要危害叶片。初期叶片上出现红色小点，随病斑逐渐扩大，病斑呈圆形，不规则形，其大小分别为直径1.5～10.0mm(平均直径5.68mm)和0.5～10.5mm×0.5～19.2mm(平均大小4.68mm×5.93 mm)。病斑边缘不明显，紫褐色，中央干枯甚至破裂，病斑稍微凹陷。病斑背面也呈紫褐色，潮湿情况下，背面有紫黑色霉状物。 2．鱼腥草紫斑病菌的分离和培养性状 经常规组织分离得到鱼腥草紫斑病菌纯培养。在PDA平板上，菌落初期白色，平伏，菌落圆形，后期变为褐色。 3．分离菌的回接与病原鉴定 分离菌回接植株出现了与田间相同症状，并从发病的部位再次分离到相同的病菌。证明该分离菌是鱼腥草紫斑病的病原菌。同时，镜检发现回接植株病叶与田间病株病叶中病菌形态相似，病原菌分生孢子梗粗3.75～6.25μm(平均4.22μm)，光滑，无色，分隔处有缢缩，顶细胞膨大成泡囊。泡囊，无色，安瓶状，直径6.25～11.25μm(平均8.27μm)。分生孢子顶生，单胞，球形或近球形，亮黑色，大小为12.50～18.75μm×12.50～21.25／μm(平均14.90μm×17.11μm)。根据以上形态特征鉴定为Nigrospora sp．。 4．鱼腥草紫斑病菌生物学特性 鱼腥草紫斑病菌(Nigrospora sp．)在PDA和PYA培养基上都能很好的生长和产孢；菌丝生长和产孢适温范围25℃～30℃；菌丝生长适宜pH 5～9，产孢适宜pH 5～7；光照条件对菌丝生长影响不大，产孢以12h荧光～12h黑暗产孢最好；碳源以葡萄糖最好，氮源以酵母浸膏和牛肉浸膏最佳，硝态氮好于按态氮。分生抱子萌发适宜温度是25℃，低于10℃抱子不能萌发;适宜相对湿度范围90%一100%和水滴中，低于50%不能萌发;适宜pH6一7;光照对抱子萌发无明显作用。5.鱼腥草紫斑病病害循环 鱼腥草紫斑病病菌以分生抱子和菌丝体在田间病株和病残体叶片病部越冬。病原菌主要以风雨传播。病原菌侵入的方式是分生抱子萌发形成芽管直接侵入，浸入部位是叶背面表皮细胞间隙。自然条件下，平均温度24.9℃、16.6℃和7.6℃时，潜育期分别为Zd、3~4d和4~sd。鱼腥草紫斑病在田间具多次再侵染。6.室内药剂筛选和田间药剂防治6.1室内药剂筛选 7种药剂(70%甲基托布津、50%多菌灵、2种植物浸提液、2种芽抱杆菌BA、BY和杨康生物菌肥)筛选结果表明，对病原菌菌丝生长和产抱抑制效果最好的是甲基托布津(l000倍)和多菌灵(l 000倍)，菌落生长和产抱抑制率75.2%和90.2%以上;生防药剂BA (500倍液)效果次之，菌落生长和产抱抑制率为522%和72.9%。对抱子萌发抑制效果最好的同样是甲基托布津(1 000倍)和多菌灵(1 000倍)，抑制抱子萌发率%%以上。其次为两种植物浸提液(6#和7“，500倍)，抑制抱子萌发率分别为92%和89%。6.2田间药剂防治 选用5种药剂(70%甲基托布津、50%多菌灵、杨康生物菌肥和生防药剂BA、BY)进行田间药效试验。结果表明，多菌灵(1 000倍)和甲基托布津(1 000倍)的防治效果最好，53.25%~53.48%。生防药剂BY(500倍液)防治效果次之，达31.0%。杨康生物菌肥(500倍液)和生防菌BA(500倍液)防治效果达22.14%。更多还原

【Abstract】 Houttuynia cordata Thunb belongs to Saururacese and Houttuynia. It is many-year-life grass plant. It is a kind of uncultivated edible and official vegetable.The purple spot of heartleaf hourtuynia is a new disease of cropping base in Sichuan, Ya’an ’SanJiu’ company. It has become the primary disease of heartleaf houttuynia. The percentage of diseased plant and leaf reached 100% and 58%, respectively. It not only affects growth and output, but reduce quality. This dissertation included the symptom characteristics , the identification of pathogen, the biology characteristics, the disease cycle and the control of disease.1. The symptom characteristics of purple spot of heartleaf houttuyniaThe disease mostly harm to leaf. The symptom of the disease is as follows: at first, there is a red spot, then, little spots become circular or irregular spots, which diameter reaches 1.5~ 10.0 mm, 0.5~19.2 mm long and 0.5~10.5 mm wide. The purple brown edging is indistinct. The center withered even break, and the disease spot is a little bit hollow.The spot on lower leaf is purple brown and there is purple and black mould in damp circumstance.2. Isolation and cultural characteristics of purple spot of heartleaf houttuyniaIsolate the diseased leaf, and gain the pathogen. The pathogen were cultured on PDA medium, the colony is hoary, circular, brown later.3. Inoculation and identificationThe diseased symptom and the pathogen characteristics of inoculated plant, were similarly to the diseased plant in field. The conidiophore wide 3.75~6.25 μm , and there is constriction on septum. The apical cell is vesicle. The vesicle wide 6.25~ 11.25 μm . Conidiospore is acrogenous, globular or approximate globular, black, diameter reaches 12.50~21.25 μm. So by these, the pathogen of purple spot of heartleaf houttuynia was identified to Nigrospora sp..4. Biological characteristics of Nigorspora sp.The best medium for the mycelia growth and spores formation was PDA and PYA. The optimum temperature and pH for the mycelia growth and spores formation were 25℃ ~30℃ and pH 5~7, respectively. Effect of illumination on the mycelia growth is insignificant. Gluocose is the best carbon sources, and Yeast extract is the best nitrogen sources for the mycelia growth and spores formation. The optimum temperature and relatively humidity (RH) for spore germinationwere 25, 90%~ 100%, respectively. But the best spore germination condition was drops of water. The spore couldn’t germinate at lower than 10癈 or RH50%. The optimum pH was 6~7, and the light was unfavorable for the spore germination.5. Disease cycle ofNigorspora sp.Nigorspora sp. over-wintering through conidiospore and mycelium on the diseased plant and leave in field . The pathogen disseminated on wind and rain, it infected host through intercellular space. When mean temperature 24.9 16.6 and 7.6, it’s latent period were 2 d 3~4 d and 4~5 d, respectively. There is reinfection in field.6. Select medicaments and field trial6.1 Select medicamentsThe inhibiting effects of 7 medicaments ( Carbendazim, Cercobin M, YangKang bio-active organic fertilizer, BA, BY, extracting solution of two plants ) on Nigorspora sp. . The results demonstrated that the best medicaments of inhibiting the mycelia growth and spores formation is Carbendazim and Cercobin M, BA is better. Carbendazim and Cercobin M strongly inhibited spore germination , the inhibitory rates were more than 96%. The extracting solution of two plants were better, the inhibitory rates was 89% and 92%.6.2 Field trial5 medicaments (Carbendazim, Cercobin M, YangKang bio-active organic fertilizer, BA, BY) were put in field trial. The results of field trial demonstrated that Carbendazim and Cercobin M were the best medicaments , control effects were more than 53%. The BY was better, control effect 31.0%. The control effects of YangKang bio-active organic fertilizer and BA were more than 22.14%更多还原