免耕稻田纹枯病越冬菌核量调查方法比较

根据免耕稻田纹枯病菌核在田间的分布特点,对纹枯病菌核量田间调查方法进行了改进。试验分别对15块免耕稻田采用传统的土壤淘洗法和直接观测法进行纹枯病越冬菌核量调查,结果表明,直接观察法测得的菌核数量远多于土壤淘洗法测得的数量,并且在省时、省力的同时也使调查结果更加真实可靠。因此,直接观察法更加适用于免耕稻田纹枯病越冬菌核数量的调查。     

小粒菌核病对水稻危害程度的调查及防治对策

小粒菌核病是近几年在北方稻作区发生蔓延的一种病害,此病在查哈阳农场有发病面积逐年扩大,危害程度逐年加重的趋势,可能成为今后危害水稻程度较重的病害之一。通过对小粒菌核病发病机理分析,认为该病的发生受田间菌核数量的影响,据此提出了防治方法。     

稻田遗留菌核存活率的研究

稻田遗留菌核存活试验表明,稻田土表和土下２ｃｍ、５ｃｍ处菌核,经过夏季高温和泥水沤淹全部腐烂,丧失生命力;田埂顶部和半坡处菌核,分别约１／３和１／１０具有生命力。     

大蒜白腐病防治技术

<正>大蒜白腐病又称大蒜菌核病,是大蒜的主要病害,在永胜县大蒜种植区域时有发生,特别是在9月初~9月中旬种植的早蒜发病较重。1发病症状大蒜白腐病在生长期和贮藏期均可发病,大蒜萌发期,带菌蒜种在表皮下形成黑色菌核,严重的直接导致不发芽或生根不良,随后蒜种表面呈水渍状凹陷,软化腐烂,表面形成白色菌丝和球形菌核,大蒜幼苗返青期受侵染的植株叶片发黄,长势极弱,由下部叶片向上部叶片发展,拔起病株,其     

气候对油菜菌核病作用机理及综防策略

为油菜菌核病的预测防治提供方法依据。用数学模型对菌核密度与气候的关系进行研究。菌核密度与2～3月平均气温、相对湿度及3～4月平均气温成负相关,与3月降雨量成正相关。菌核密度代表发病程度,发病程度由气候决定,气候在花期病害中有直接和间接两种作用方式。坚持＂抗、避、灭、防＂的综防策略。     

宣城市油菜菌核病的防治对策

宣城市是安徽省皖南油菜的主要种植区,常年种植面积6万公顷左右。菌核病常年呈中等偏重发生。这与宣城市的气候条件密切相关。1降低田间菌核数量1.1轮作换茬研究表明,水旱轮作如油菜—水稻,可显著地降低菌核数量,从而降低发病率。1.2化学防除田埂等空闲地菌核稻田遗留菌核存活试验表明,稻田土菌核经过夏季高温和泥水沤淹全部腐烂,丧失生命力,而田埂顶部和半坡处菌核,分别约1/3和1/10具有生命力。应在3月油菜抽薹、菌核萌发初期进行药剂防治,减少初侵染源。1.3降低菌核数量的措施应连片应用油菜菌核病子囊孢子可以通过风进行远距离传播。因此…     

大棚芹菜菌核病的综合防治

大棚芹菜菌核病近几年来发生较重,严重时成片绝收。病害常先在叶部发生,形成暗绿色病斑,潮湿时表面生白色菌丝层,后下蔓延,引起叶柄及茎发病。病处初为褐色水渍状,后形成软腐或全株溃烂,表面生浓密的白霉,最后形成鼠粪状菌核。病菌以菌核在土壤或混杂的种子中越冬,为次年     

水稻纹枯病、稻曲病的发生特点与防治技术

纹枯病和稻曲病是水稻主要病害，这二个病害发生有以下几个特点，防治中必须予以注意： 1、水稻纹枯病 1．1常发性．田块间病情差异大。这主要是土壤带菌（以菌核在土壤中越冬），所以年年发病都重，又由于不同田块菌源多少大不一样，老病田残留菌核量大，每年都发病严重。轻病田残菌核量少，相对发病就轻，所以重病田老病田防治要早，下药要重些。     

象山县水稻稻曲病成灾机制与综合防治对策

对水稻稻曲病成灾机制和综合防控技术研究的相关进展进行了评述。水稻品种生育期过长、灌浆期温度相对较低是稻曲病在浙江省成灾的根本原因;高感品种的大范围推广和对高水肥的需求增加了稻曲病的成灾概率;稻田冬前免耕大大提高了稻曲病菌菌核的越冬比例,增加了翌年稻曲病菌侵染的菌源量。稻曲病防治的基本措施是减少菌核和厚垣孢子的越冬数量;水稻收获后稻田及时翻耕、选择生育期较短的品种、适当减少氮肥用量、使用降解菌核的微生物制剂、孕穗期喷洒杀菌剂等均可有效减轻稻曲病的发生。     

水稻病害绿色防控措施

稻田生态系的生境结构和小气候比较简单,而且只有相对较少的资源,因为,稻田生态系中的物种多样性越少,空余生境生态位就越多,这就导致稻田生态系统极不稳定,病虫害发生频繁,产量品质易被影响。1.选用抗病品种。结合当地天气、病虫害发生情况,选择适宜抗病品种。2.打捞菌核。根据病害后期形成的菌核会掉落在稻田里成为下一年的病原这一特点,在耕沤田时,     

氮素营养对水稻纹枯病菌生长的影响

结果表明病菌对不同氮源的利用能力不同，但趋势基本一致：在无氮源或氮源浓度水平很低的情况下，菌落直径增加快，气生菌丝较少，无或极少菌核形成；随着含氮水平的提高，菌落直径增加减缓，气生菌丝和形成菌核数量增加。此外，不同寄主秸秆培养基对病菌生长和致病性也有一定影响。     

Mycoparasitism of Nematode-Trapping Fungus Monacrosporium ellipsosporum and Its Biochemical Basis

Monacrosporiumellipsosporum, a nematode-trapping fungus, was isolated by baiting with sclerotia of Sclerotinia sclerotiorum in soil from a tobacco field in Yuxi, Yunnan Province. Colonization frequency of the sclerotia by the fungus was 18% in natural soil. Reinoculation tests by placing surface-sterilized sclerotia on fungal cultures for two weeks and then surfacesterilized again led to 32% sclerotia be infected. Dual culture tests in PDA plates did not give rise to a suppression zone between the colonies of M. Ellipsosporum and its counterpart fungi S. Sclerotiorum and Rhizoctonia solani, suggesting there was little or no nutritional competition and absent of antifungal compounds. However, M. Ellipsosporum could grow over absent of S. Sclerotiorum and R. Solani, and significantly inhibited their growth on agar plates. Scanning electron and light microscopic observations showed thathyphae of M. Ellipsosporum grew along and appressed on hypha of S. Sclerotiorum and coiled around hyphae of R. Solani. Assays of cell wall-degrading enzymes showed that M. Ellipsosporum grew well in chitin agar media, with clear transparent hydrolysis zones. Activities of total chitinase, exo-chitinase, β-1, 3-glucanase and protease were 140.2±11.9, 82.9±4.1, 111.2±7.6 and 76.1±4.3 U respectively, after incubation for 4 days at 30℃ in liquid media containing ground sclerotia of S. Sclerotiorum as sole nutrient source. These enzymes might be important in the mycoparasitic activity of M. Ellipsosporum.     

Population Dynamics and Survival of Rhizoctonia solani AG-1 in Field Soil Under Rice-Wheat Rotation

A field under rice-wheat rotation was selected near Chengdu, China, to study the population of Rhizoctonia solani anastomosis group 1 (AG-l), pathogen causing rice sheath blight disease, in natural soil ecosystem. Inocula of the fungus recovered from the field were divided into three types, i.e., sclerotia, free mycelium retained in the soil passed through a 0.355mm sieve, and colonized plant debris which was subdivided into small colonized debris retained between 2.00 and 0.355mm sieves and large colonized debris retained on 2.00mm sieve after wet screening. Quantitative estimation of the three types of inocula in one year indicated that small colonized debris was the dominant inoculum type for most of the time. The population peaked in March and September at 1 210and 480 colonized debris 100 g-1 air-dry soil respectively, and fell down in December and August to 0 and 177 colonized debris 100 g-1 air-dry soil respectively. Free mycelium was only detectable in March, September and October with 1 209, 7.9 and 14.5 μg fresh wt myceliumg-1 air-dry soil respectively, which corresponded to the two peaks and the second highest level of small debris density in the year. Viable sclerotia and large colonized debris were rare with populations ranging from 0 to 3 for sclerotia and 0 to 14 for large colonized debris 100 g-1 air-dry soil, but were the main structures to survive over winter. It was expected that soil temperature was the main factor determining population dynamics of R.solani AG-1 in natural soil. Optimum temperature for population increasing is predicted to be around 15℃, with a range from 10 to 25℃. Viability tests indicated that 60.9% sclerotia could survive after 265 d being buried in natural sandy loam in field conditions in Beijing, while colonized rice straw debris (0.5 - 1.0 cm long) could not yield the fungus on medium plates after 88d of being buried under the same conditions.     

核盘菌菌核重寄生菌的分离筛选

从云南、四川、甘肃、陕西、山西、湖南、河北、北京、黑龙江、吉林、辽宁、内蒙古等12个省市(区)采集土样103份,采用室内菌核诱捕的方法分离得到了148个真菌菌株,分别属于12个属。其中黏帚霉属(Gliocladium spp.)77个菌株,包括4个种,占全部分离菌的52.03%,为优势种群;其次为青霉菌(Penicillium spp.)21个菌株,分离率为14.19%;镰刀菌(Fusarium spp.)16个菌株,占10.81%;木霉菌(Trichoderma spp.)13个菌株,占8.78%;轮枝菌(Verticillium spp.)8个,占5.41%。对其中寄生率较高的菌株进行回接,结果表明,黏帚霉和木霉寄生核盘菌(Sclerotiniasclerotiorum)菌核的能力强,接种1周后导致菌核腐烂,但不同菌株之间存在差异;而镰刀菌、轮枝菌对菌核的寄生能力较差。并且,首次用菌核诱捕的方法从云南省玉溪市烟草田土壤中分离获得了一株能寄生菌核的捕食线虫丝孢菌,经鉴定为椭圆单顶孢[Monacrosporium ellipsosporum(Preuss)Cooke&Dickinson]。     

龙血树白绢病病原的鉴定及生物学特性研究

对龙血树白绢病病原菌进行分离、鉴定和生物学特性的研究,结果表明,龙血树白绢病的病原菌为齐整小核菌Sclerotium rolfsii Sacc。在30℃、pH值为5.0～6.0的条件下适宜该菌菌丝生长;菌核在25～30℃时形成量最多,最适于菌核萌发的温度为30～35℃、pH值为4.0～7.0;40℃以上高温抑制菌核的形成。病菌能利用多种碳源、氮源,有无光照都能很好生长。     

THE LAWS OF DISTRIBUTION OF PARTICLES IN SUSPENSION

Viable sclerotia of the cotton root-rot fungus, Phymatotrichum omnivorum, have been found under natural conditions in the soil of infested cotton fields in Texas, showing that this fungus is a soil organism not restricted to living roots of susceptible host plants, but having an independent means of over-wintering and dissemination.     

6种培养基对不同来源白术白绢病菌培养的影响

6种培养基对不同来源白术白绢病菌培养的影响研究结果表明,6种培养基上,4个不同来源地菌株菌丝生长和菌核产量存在一定的差异,尤其是菌株LA20,在几种供试培养基上长势均较其他3个菌株差,产核量也最少。比较几种培养基上供试菌株生长状况和产核量的关系发现,供试4个菌株产菌核量与菌丝的生长状况呈一定的正相关关系,即在同一个培养基上菌株菌丝生长越好,产核量也越多。     

黑龙江省向日葵菌核病菌生物学特性及抗药性初步测定

选择了5株具有代表性的向日葵菌核病菌,初步测定了其生物学特性及其抗药性。结果表明,向日葵菌核病菌菌丝生长的最适温度在15～20℃之间;菌丝生长最适环境为中性和偏酸性;越冬条件下不同菌核及病残体埋入土壤中,病残体上菌丝不能越冬,而菌核能够越冬,且埋入土层越深菌丝生长速度越慢,产生菌核的重量也降低;向日葵菌核病菌对茄子、向日葵、油菜、向日葵的致病力存在差异;多菌灵对不同地理区域菌株的EC50为0.4977～0.2456μg.mL-1,其中最不敏感菌株与最敏感菌株EC50的比值为2.03,都为敏感菌株;腐霉利对不同地理区域菌株的EC50为1.2715～0.3333μg.mL-1,其中最不敏感菌株与最敏感菌株EC50的比值为3.81,都为敏感菌株,目前所采集的地点尚未出现抗药性菌株。研究为深入研究黑龙江省寒地向日葵菌核病菌的生物学特性及科学防控奠定了良好的基础。     

猪苓菌培养特性研究进展

阐述了猪苓菌的形态结构、适生条件、营养特性、培养基配方、适生树种及猪苓菌与伴生菌、蜜环菌的相互关系和诱导猪苓菌丝扭结形成菌核的相关因子,以期为猪苓菌的深入研究和人工栽培提供参考。