哈茨木霉防治茉莉白绢病效果试验

1977年从水稻叶面分离获得木霉82(T—82)经鉴定为哈茨木霉Trichoderma harzianum Rifai。用这种木霉的分生孢子浓度0.5％和0.7％,防治茉莉白绢病Sclerotium rolfsii,效果分别为97.62％和100％。本文也讨论了防治机理,以及对其它病原真菌的拮抗作用。     

Effect of sulfite-hydrosulfite and nitrite on thiol redox state, oxidative stress and sclerotial differentiation of filamentous phytopathogenic fungi

This study shows that Na₂S₂O₄, Na₂SO₃ and NaNO₂ decreased differentiation of filamentous phytopathogenic fungi representing the four main types of sclerotia at maximum growth non-inhibiting concentrations, and also increased and decreased the oxidized and the reduced components of their thiol redox state, respectively. Na₂S₂O₄, Na₂SO₃ and NaNO₂ also severely inhibited fungal growth at certain concentrations. These effects concurred by the increase of the high oxidative stress indicator lipid peroxidation and could be attributed to the oxidative cytotoxicity of sulfites and nitrite. The cytotoxic mechanism of the latter may be related to the acidic pH. Sulfites and nitrite can be used as potent fungicides against sclerotiogenic phytopathogenic fungi by acting as growth inhibiting cytotoxic oxidants and by sustaining fungi in their undifferentiated hyphal stage, in which they are more vulnerable to degradation by soil microorganisms.     

Integrated control of Allium white rot with Trichoderma viride, tebuconazole and composted onion waste

Two isolates of Trichoderma viride (L4 and S17A) were assessed for biological control of Allium white rot (AWR) with different onion accessions and cultivars, alone and in combination with a tebuconazole-based seed treatment or composted onion waste. In glasshouse tests, 23 new bulb-onion accessions from previous work to detect resistance to Sclerotium cepivorum showed no differences in susceptibility to AWR but, when combined with S17A, disease was reduced by up to two-thirds over all accessions. Trichoderma viride L4 and S17A also reduced the proportion of infected plants for five commercial bulb-onion cultivars and one advanced breeding line by at least one-third. Further glasshouse tests using a salad-onion cultivar showed that L4, S17A, tebuconazole or composted onion waste controlled AWR and at least halved the proportion of diseased plants. Combination treatments of T. viride with either tebuconazole or compost enhanced control and, in some treatments, disease was almost eliminated. In field trials, control of AWR by S17A was significant for 17 out of 18 individual or mixed bulb-onion accessions, with disease reduced overall by more than half. In another field experiment, S17A failed significantly to reduce AWR for two out of three commercial bulb-onion cultivars, while tebuconazole reduced the final proportion of AWR-infected plants over all cultivars from 0·47 to 0·09. Combining S17A and tebuconazole resulted in a similar level of AWR to using tebuconazole alone. The use of T. viride in an integrated strategy with other treatments to enhance control of S. cepivorum is discussed.     

加工型辣椒品种对细菌性叶斑病的抗性鉴定

由黄褐假单胞Pseudomonas fulva侵染引起的辣椒细菌性叶斑病是近期在新疆北疆加工辣椒生产区发现的一种新病害。为评估辣椒品种对细菌性叶斑病的抗性水平,采用苗期人工接种结合田间调查,鉴定了生产中13个主栽辣椒品种对细菌性叶斑病的抗性。结果表明,供试材料对细菌性叶斑病均无免疫性,但不同辣椒品种对辣椒叶斑病抗性差异较大,‘改良佳线1号’和‘丰力红冠’为抗病品种;‘佳线4号’、‘新丰6号’、‘秦椒王’、‘陕早红’、‘宝丰2号’为耐病品种;‘红安6号’、‘朝天椒’为感病品种,高感品种为‘金塔’、‘铁皮椒’、‘红龙13’和‘超级韩国甜椒’。研究结果为辣椒的抗病育种和病害防治提供了基础。     

花生白绢病研究进展

花生白绢病是世界花生上发生的一种重要土传真菌性病害,近十年来在我国山东、河南、广东、辽宁、江西等主要花生产区发生为害逐年加重,已成为制约花生产量和质量的重要因素。本文对花生白绢病的发生为害、病原菌的生物学特性与变异、病害流行和防治等方面进行综述,并对今后花生白绢病研究提出一些建议,以期为我国花生白绢病工作者提供参考。     

保护地蔬菜菌核病的发生及防治

[目的]研究保护地蔬菜菌核病的发生及防治技术。[方法]在2003~2006年研究菌核病病原菌侵染循环的基础上,探讨菌核病的综合防治方法。[结果]蔬菜菌核病病菌多为核盘菌,在土壤中以菌核的形式越冬,形成第2年的侵染源。幼嫩果实较老熟果实容易发病。温度20℃左右,大棚相对湿度在85%以上,有利于病菌发育,发病较重。蔬菜栽植密度过大和病田连作地菌核病发病较重。生态防治菌核病的措施包括深翻灌水、覆膜栽培、种子处理(温汤浸种或药剂浸种)、清洁田园、高温闷棚,均能控制病害的发生。1 000~1 500倍液的50%腐霉利、50%异菌脲、50%乙烯菌核利等可湿性粉剂对保护地蔬菜菌核病的防效较高。植株生长后期,仍要重点防治根茎部。[结论]该研究明确了菌核病病原菌的侵染循环途径,制定了以生态措施为主的有效防治措施。     

环境因素对禾谷丝核菌菌核形成的影响

为了探讨影响禾谷丝核菌（R．cerealis）菌核形成的主要因素,在不同温度、培养基酸碱度、光照、碳氮营养等条件下对R．cerealis的生长状况和菌核形式进行了观察和分析。结果表明,温度、pH值、光照、碳氮营养对R．cerealis菌核的形成均有极显著影响。R．cerealis菌核形成的适宜温度为18～25℃,适宜pH值为5．0～7．0,暗培养或光暗交替培养有利于菌核形成;在碳、氮营养中,葡萄糖和NO3^--N最有利于R．cerealis菌核的形成,L-脯氨酸和L-亮氨酸可抑制菌核形成,但对菌丝生长无不良影响。     

石柱黄连白绢病调查及影响因子分析

[目的]掌握黄连白绢病的发病条件、危害程度及发病规律,为生产上白绢病毒的科学防控提供理论指导。[方法]通过一般性走访调查,了解白绢病发生情况,并采取样地田间调查研究的方法,定期统计发病率及危害程度,分析相关影响因子。[结果]黄连白绢病发病率高,影响因素复杂,生长期、植龄、海拔、耕作制度、坡度、土壤类型盈周围生态环境等因素均对黄连白绢病的发生有重要影响,危害重者发病率可达30．0％,并造成减产乃至绝收。[结论]黄连白绢病已成为影响黄连生产的重要病害。     

部分糖类及化感物质对白术白绢病菌与根腐病菌的影响

研究了部分糖类、氨基酸、酚类、有机酸类、白术汁和白术粉对白术白绢病菌及根腐病菌生长与繁殖的影响。结果表明,蔗糖、葡萄糖、麦芽糖、鼠李糖和甘露糖对白绢病菌和根腐病菌菌丝的生长都具有明显的促进作用,而乳糖、D-果糖、木糖对菌丝的生长有抑制作用。L-组氨酸、L-异亮氨酸、酪氨酸、精氨酸、丝氨酸、脯氨酸和硝酸钾能明显促进白绢病菌和根腐病菌的菌落生长,而天门冬氨酸和半胱氨酸对2种菌均有较强的抑制作用。咖啡酸乙酯和香兰素对白绢病菌和根腐病菌有很强的抑制作用,儿茶素和咖啡酸对白绢病菌却有促进生长的作用,但是多数化感物质对2种菌的生长影响较小。几种浓度的白术汁和白术粉培养基对白绢病菌和根腐病菌的生长有促进作用,其效果与10％和5％的马铃薯培养基相近。不同的碳源、氮源和化感物质对白术白绢病菌和根腐病菌生长的影响是不同的。     

广西水稻上嗜水小核菌的鉴定及系统发育研究

 从类似纹枯病的水稻病株上分离到一种在菌核形态上与纹枯病菌(Rhizoctonia solani)有明显差异的真菌,致病性测定结果表明该菌能侵染水稻、玉米和大豆。对该菌的显微形态、生物学特性以及核糖体DNA-ITS序列进行研究,结果表明该菌为嗜水小核菌(Sclerotium hydrophilum Sacc.)。病菌在30℃、pH为6~9条件下生长表现最佳,属硫胺素自养型菌;营养菌丝与立枯丝核菌相似,菌核球形或椭圆形,数量极多,其平均大小仅为386.4μm×420.7μm;该菌的核糖体DNA-ITS序列与GenBank中唯一一个嗜水小核菌(登录号为DQ875597)的同源性为99.5%,并且与大多数丝核菌(Rhizoctonia spp.)也有一定的同源性,病菌的28S rDNA-RFLP分析结果进一步说明了该菌在系统发育上与丝核菌类真菌具有较高的同源性。通过比较该菌和几种与水稻纹枯病相关丝核菌核糖体DNA-ITS序列的差异,设计了一对特异性引物PS-1和PS-2,能专一地从被该菌侵染的水稻感病组织中扩增出一段约550bp的DNA。