用木霉防治作物白绢病

白绢病Sclrotium rolfsii Sacc.是作物根部的一种严重病害,除小麦、玉米等禾本科作物外,花生、大豆、辣椒、茄子、苹果、草莓、西瓜、甜叶菊等油料、果树及蔬菜作物;白术、人参、玄参、白芍、附子、地黄等药用植物;茉莉、杜鹃、兰花、菊花等花卉植物都能发生。以茉莉、白术、花生受害最重。 在作物整个生长期间都能发生,幼苗发病常可在几天内死亡。在浙江,茉莉、白术因此病死亡常达20—50％以上。多年生木本作物如茉莉、苹果,成年树受害通常当年不     

搞好茉莉花苗白绢病的检疫和防治

白绢病是茉莉花苗的危险性病害之一。我所1981年春从外地引进茉莉花苗,带入白绢病“菌核”,致使植后发病严重,损失很大。当时采取化学防治措施,用20%甲基托布津可湿性粉剂500倍药液灌兜,收到显著效果。作者认为:对茉莉花苗白绢病的防治,应贯彻“预防为主,综合防治的方针”,首先要重视建立无危险性病虫害的苗圃,减少危险性病害传入的机会。     

辣椒白绢病的发生与防治

辣椒白绢病Sceerotium rolfsii Sacc危害近土表茎基和根部的皮层,使茎基和根部皮层腐烂,甚至全株死亡,初次侵染源主要来自残留于土壤和病残体中的菌核与菌丝体。该病过去常在辣椒生育后期偶尔发生,对产量影响较小。近年来病情发展快,特别是蔬菜区,发病早危害重,在辣椒生育中后     

魔芋白绢病初侵染来源试验

安康地区魔芋种植面积为 5.3万ｈｍ2 ,约占全国种植面积的 1 / 6,年产值过亿元 ,魔芋已被列入安康地区农业产业化的重点项目。但随着魔芋种植面积的扩大 ,白绢病发生和为害程度逐年加重 ,国内还未见其初侵染来源的研究和报道。为此 ,在近几年生产调查的基础上 ,于 1 999年开展此项试验 ,为指导大田防治提供科学依据。1　材料与方法试验设①切芋播种 ,每窝在种芋旁放入少量带白绢病的菌核土 ;②整芋播种 ,每窝在种芋旁放入少量带白绢病的菌核土 ;③整芋播种 ,用上年魔芋白绢病发生严重田块的带病土壤 0 .2 5ｋｇ覆盖种芋 ;④整芋播种 ,不作处…     

生物农药哈茨木霉防治白术白绢病

白术(Atract ylodes macrocephala koidz)是著名的中药“浙八味”之一,以根状茎入药,分布于长江流域各省区,仅在浙江栽培面积即达2万亩。长期以来,白术白绢病病原菌(Sclerotium rolfsii)一直是白术生产中的严重威胁,常年损失为20～40％,大发生年份损失高达50％以上。以往常用多菌灵、托布津等化学农药防治,均无明显效果。虽然五氯硝基苯防治白术白绢病效果较好。但由于有机氯的残留严重,不宜在中药材中使用。为此,我们自1988年起,在白术主产县浙江磐安应用哈茨木霉(Trichoderma harzianum)对白术自绢病进行生物防治的研究,获得了良好的效果。     

江阴县1962年水稻白叶枯病发生情况的调查报告

一、白叶枯痫发生情况 白叶枯病是我县水稻生产上的主要病害。1962年中稻发病比常年早半个月左右,6月底始见发病中心;7月中、下旬普遍见病;8月初正值水稻抽穗破口时期,碰上8级台风及暴雨(46.4毫米),病害迅速蔓延,无论是沿江、沿山、平原或山区都有发病。不仅中稻发病,就是晚稻、籼稻发病亦重,但受害面积与程度,仍以中稻最为严重。 此病直接影响水稻抽穗灌浆,致使千粒重大大     

魔芋白绢病发生危害与综合防治

魔芋白绢病主要发生在接近地面 1～2cm的植株基部。初侵染源为土壤中的菌核和病残体及带病种芋。大田 6月中下旬开始发病 ,8月上旬至 9月上旬高温高湿条件下危害最重 ;随着种植年限增加 ,田间菌量累积 ,病害逐年加重 ;植株受机械损伤有利于病菌侵入。建立种芋基地 ,选用抗病品种 ,实行轮作倒茬、拔除病株、推行荫蔽栽培和增施钾肥等措施可减轻发病 ;化学防治应采取土壤消毒、种芋处理和大田统防统治等措施控制魔芋白绢病发生危害     

哈茨木霉防治花生、甜椒白绢病

1977年作者从水稻叶面分离得到哈茨木霉Trichoderma harzianum Rifai(即木霉82,以下简称木霉),经拮抗作用测定,发现其对白绢病菌(Sclerotium rolfsii)菌丝具有很强的溶解作用,对菌核有寄生作用。1981年以来,在各地应用木霉防治茉莉、白术白绢病取得了良好效果。本研究是     

黄姜白绢病的发生及防治方法

黄姜白绢病是由齐整小菌核菌[Sclerotium rolfsii Sacc=Cortcium rolfsii(Sacc)Curzi．]引起的一种新病害。记述了病原、症状、发生规律和综合防治方法。     

茄子白绢病的防治技术

白绢病属土传真菌性病害，病原菌无性阶段称齐整小菌核菌（SclerotiumrolfsiiSacc．），有性阶段为罗代阿太菌〔Atheliafolfsii（Curiz）Tu＆Kimbiough〕。此病寄主广泛，仅蔬菜就有２０种以上，如黄瓜、西瓜、苦瓜、南瓜、茄子、番茄、辣（甜）椒、韭菜、菜豆、扁豆、胡萝卜、马铃薯、黄花菜、百合、魔芋、菊花等。白绢病在南方多见，在北方发生较少。２０００年春季，河南西部温室中茄子白绢病发生较重，病株率达１０％～２０％，实属少见。为此笔者对温室白绢病做了调查，同时采取了多种措施开展防治，取得了良好防治效果。１症状及发…     

First report of southern blight of common barley in Puerto Rico

In 1990–91, 96% of the test plants in a barley (Hordeum vulgare L.) winter nursery in Puerto Rico was lost toSclerotium rolfsii. Small necrotic lesions (1–3 mm long) developed at the base of the stem, followed by wilting and general chlorosis as the lesions progressed and eventually girdled the base of the stem. Sclerotia then developed on the plants at the stem base. Two morphologically different strains ofS. rolfsii that were mycelial incompatible were isolated. This is the first report of a destructive blight due toS. rolfsii on field barley in the Caribbean. The apparent rate of disease increase (r) was estimated to be 12.2% per day using the logistic model, with an initial disease incidence of 0.042% (R²=0.89, p<-0.001).     

Etiology of and effect of environmental factors on damping-off and stem rot of cowpea in Benin

Damping-off and stem rot are two types of diseases affecting cowpea (Vigna unguiculata (L.) Walp.) in the Quémé Valley, Benin. Of the fungal species isolated from diseased plants in the field during a 2-year experiment (2001 and 2002),Sclerotium rolfsii Sacc. was found to be solely responsible for these diseases. The disease incidence decreased with increasing distance of the field from the river. Measurement ofS. rolfsii initial inoculum, soil moisture and disease incidence in cowpea field plots revealed a positive correlation among these parameters. The multiple regression analysis showed that the disease incidence increase was 0.4% for one unit increase in soil moisture percent, whereas the disease incidence increase was 19.8% for one unit increase of the density of initial inoculum of the pathogen. This is the first comprehensive study of the effects of environmental factors on the incidence of cowpea damping-off and stem rot caused byS. rolfsii in Benin, and shows that the density of the initial inoculum is the main contributing factor of the disease in the field in the Quémé Valley. http://www.phytoparasitica.org posting Dec. 19, 2004.     

Induction of resistance to Sclerotium rolfsii in different varieties of onion by inoculation with Trichoderma asperellum

We evaluated the ability of Trichoderma asperellum Samuels, Lieckfeldt & Nirenberg to induce resistance to the fungal plant pathogen, Sclerotium rolfsii Saccardo, in three onion (Allium cepa L.) varieties. Both the severity of disease and the activities of glucanase, chitinase and peroxidase (enzymes involved in plant resistance) were evaluated in onions inoculated with T. asperellum alone, S. rolfsii alone, or both T. asperellum and S. rolfsii (dual-inoculation) and compared to uninoculated (control) plants. In dual inoculations, the presence of T. asperellum reduced the severity of disease symptoms caused by S. rolfsii. Inoculation with T. asperellum alone increased glucanase, chitinase and peroxidase activity in bulbs, roots and leaves of all three onion varieties compared to uninoculated controls; bulbs of the variety Red Satan (RS) had the highest enzyme activity. In plants inoculated with S. rolfsii alone, enzyme activity was only increased in bulbs and roots compared to uninoculated controls. The highest levels of enzyme activity also occurred only in bulbs and roots of plants that had been dual-inoculated with T. asperellum and S. rolfsii. Plants of the RS variety showed the highest enzyme activities (both constitutive and induced) and showed the lowest severity of disease. Therefore, application of T. asperellum has potential as a biological control alternative to synthetic fungicides for protection of onion crops against infection by S. rolfsii. This protection depends on both constitutive and induced defence responses and varies amongst onion varieties.     

Selective accumulation of Trichoderma species in soils suppressive to radish damping-off disease after repeated inoculations with Rhizoctonia solani, binucleate Rhizoctonia and Sclerotium rolfsii

Artificial suppression of radish damping-off disease was induced by repeated soil inoculations with Rhizoctonia solani, binucleate Rhizoctonia (BNR) and Sclerotium rolfsii in pot systems. Soils repeatedly inoculated with R. solani and BNR showed suppressive to disease caused by R. solani and S. rolfsii, while soils repeatedly inoculated with S. rolfsii were suppressive to disease caused by S. rolfsii but not by R. solani. Species of Trichoderma were consistently isolated from soils repeatedly inoculated with R. solani, BNR and S. rolfsii. These Trichoderma spp. accumulated selectively in relation to the fungal species that was repeatedly added to the soils. The ratios of the frequencies of T. viride, T. harzianum and T. hamatum were 5:2:2 and 8:5:2 in soils repeatedly inoculated with R. solani and BNR, respectively. In S. rolfsii- inoculated soils, T. koningii was predominantly isolated. T. viride, T. harzianum and T. hamatum isolates obtained from either R. solani or BNR after repeated additions to the soils suppressed radish damping-off disease caused after challenge inoculations with R. solani or S. rolfsii. Among the Trichoderma species, T. viride consistently yielded high levels of suppression. However, isolates of T. koningii obtained from S. rolfsii-infested soils suppressed disease caused by S. rolfsii but failed to suppress disease caused by R. solani. Generally, the species of Trichoderma accumulated in a selective pattern that was closely related to the species of fungal pathogen used to induce the suppressive soil.     

Association of seedling and adult plant resistance to <Emphasis Type="Italic">Sclerotium rolfsii</Emphasis> in Jerusalem artichoke (<Emphasis Type="Italic">Helianthus tuberosus</Emphasis> L<Emphasis Type="Italic">.</Emphasis>) under field conditions

Stem rot caused by Sclerotium rolfsii is an important problem for Jerusalem artichoke production. Host plant resistance is the most promising method to control disease. If resistant genotypes can be identified in seedlings and this resistance is closely related to resistance at maturity, the evaluation of disease resistance in adult plants could be curtailed or omitted, increasing the speed and efficiency of screening. The objective of this study was to determine the relationship between resistance to S. rolfsii in Jerusalem artichoke in seedling and in adult stages under field conditions. Field experiments were set up in different soil fertility environments in the rainy season during July to October 2014. In each environment, 10 varieties of Jerusalem artichoke with differences in resistance to S. rolfsii were planted and inoculated either 15 or 45 days after transplanting. Higher disease incidence was observed on adult plant stage, but disease severity was similar for both plant stages. The correlations between seedling and adult responses were positive and significant for disease incidence, area under disease progress curve and severity index. Screening for resistance to S. rolfsii in Jerusalem artichoke can be carried out on seedlings, thus improving the efficiency of selection.     

<Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> inhibits the plant cell wall degrading enzymes of <Emphasis Type="Italic">Sclerotium rolfsii</Emphasis> and reduces the severity of groundnut stem rot

Three hundred and ninety-three groundnut-associated bacterial strains, applied both as seed treatment and soil amendment, were evaluated for control of stem rot disease (caused by Sclerotium rolfsii) of groundnut in a controlled environment. Twelve strains significantly (P=0.01) reduced the incidence of stem, rot of which groundnut seed endophytes Pseudomonas aeruginosa GSE 18 and GSE 19 reduced the seedling mortality by 54% and 58%, compared to the control. In dual cultures, the 12 biocontrol strains reduced the mycelial growth of S. rolfsii by 32%–74% as compared to the control. Cell- free culture filtrates of P. aeruginosa GSE 18 and GSE 19 inhibited the activity in vitro of the cell wall-degrading enzymes (CWDE) polygalacturonase and cellulase by S. rolfsii up to a maximum of 55% and 50%, respectively, when measured 6 days after inoculation. Pseudomonas aeruginosa GSE 18 and GSE 19 with a known tolerance to thiram, a commonly used seed dressing fungicide, suppressed the growth of S. rolfsii, inhibited the activity of CWDE, and reduced the incidence of stem rot, suggesting the usefulness of these biocontrol strains as components in the integrated management of groundnut stem rot.     

Pathological studies on the southern blight of China aster (<Emphasis Type="Italic">Callistephus chinensis</Emphasis>) caused by <Emphasis Type="Italic">Sclerotium rolfsii</Emphasis>

A severe outbreak of southern blight disease of China aster was observed during the post rainy season (September–November 2015) in the Mysore and Mandya Districts of Karnataka, Southern India. The disease incidence ranged between 12 and 47%. The typical disease symptoms include water-soaked lesions on leaves, stems and on the lower stem surfaces followed by quick wilting of the whole plant with abundant production of sclerotia near the stem-soil interface. The associated fungal pathogen was isolated on potato dextrose agar (PDA) medium, on which numerous reddish-brown sclerotia were seen. A total of 26 fungal isolates were isolated and studied for the mycelial compatibility. Isolate SrCCM 1 was used for pathogenicity analysis. The results of the study showed that, there was no variation among the isolates tested. Molecular identification of the pathogen by ITS-rDNA sequences of S. rolfsii showed 100% similarity with reference sequences. Based on the cultural, morphological and molecular characteristics, the fungal pathogen was identified as Sclerotium rolfsii Sacc. (Sexual morph: Athelia rolfsii (Curzi) C.C. Tu & Kimbr). Pathogenicity tests were performed on healthy leaves, roots and stems. Typical disease symptoms on leaves, stems and roots were evident after 5, 8 and 10 days of post-inoculation. Sclerotium rolfsii is known to cause diseases in economically important crop plants. However, no reports are available on the occurrence of S. rolfsii on China aster in India.     

Pseudomonas Fluorescens UP61 Isolated From Birdsfoot Trefoil Rhizosphere Produces Multiple Antibiotics and Exerts a Broad Spectrum of Biocontrol Activity

The efficient use of rhizospheric microorganisms to control plant pathogens has been reported worldwide in different plants. Pseudomonas fluorescens UP61 is a biocontrol strain isolated from the rhizosphere of Lotus corniculatus(birdsfoot trefoil) from Uruguayan soils. This strain exhibited in vitro antagonistic activity against a broad spectrum of fungal and bacterial phytopathogens. It was an effective biocontrol agent in different hosts, reducing the disease incidence caused by Sclerotium rolfsii in beans and Rhizoctonia solani in tomato. P. fluorescens UP61 produced three antibiotics possibly involved in its biocontrol activity: 2,4-diacetylphloroglucinol, pyrrolnitrin and pyoluteorin. Molecular techniques such as 16S rDNA RFLP, RAPD and rep-PCR, and partial sequence of the phlD gene, revealed the similarity of UP61 with other biocontrol strains isolated worldwide that are able to produce these antibiotics.     

Control ofRhizoctonia solani andSclerotium rolfsii in the greenhouse using endophyticBacillus spp.

Isolates of different endophytic bacteria were recovered from surface-disinfected seeds obtained from commercial companies, plants in the field and tissue culture. The bacteria were isolated from seeds after stringent surfacedisinfection.Pseudomonas fluorescens (isolate no. 14) from bean inhibited growth of all fungi tested and was fluorescent on King B medium.Bacillus cereus fromSinapis (isolate no. 65) inhibited growth ofRhizoctonia solani, Pythium ultimum andSclerotium rolfsii and also exhibited chitinase activity.Bacillus subtilis from onion tissue culture (isolate no. 72) inhibitedR. solani andP. ultimum growth.B. cereus from cauliflower (isolate no. 78) inhibited growth ofR. solani. B. pumilus from sunflower (isolate no. 85) inhibited growth ofR. solani andS. rolfsii. B. cereus (isolate no. 65) was introduced into cotton, and by using radioactive labelling we found that it was present for 16 days in the root-stem junction. It is most likely that these bacteria were still found 72 days after their introduction in the root and stem, at levels of 2.8·10⁵ and 5·10⁴ cfu g^–1 fresh weight, respectively, when selective medium was used. There was no difference between control and treated plants in their height or in the fresh weight of roots, stems and leaves.When cotton seedlings were inoculated withB. cereus (isolate no. 65),B. subtilis (isolate no. 72) orB. pumilus (isolate no. 85), disease incidence caused byRhizoctonia solani was reduced in the greenhouse by 51%, 46% and 56%, respectively. In bean seedlings inoculated withB. subtilis (isolate no. 72),B. cereus (isolate no. 78) orB. pumilus (isolate no. 65), disease incidence caused bySclerotium rolfsii was reduced by 72%, 79% and 26%, respectively, as compared to control. In both cotton and bean seedlings, these endophytes reduced the disease index more than 50%. These results indicate that endophytic bacteria can survive inside cotton plants and are efficient agents for biological control against plant pathogens under greenhouse conditions.     

Pseudostem rot caused byCorticium rolfsii,a new disease ofMusa sp. in Tamil Nadu,India

In 1987 a new disease, called pseudostem rot, was observed on 3–5-month-old banana plants(Musa sp.) cv. ’Robusta’. The pathogen was isolated in pure culture and identified asCorticium rolfsii (Sacc.) Curzi, teleomorph ofSclerotium rolfsii Sacc. The teleomorphic stage of the fungus was observed inside the pseudostem sheath. The pathogen produced leaf spot diseases (by basidiospores) on 16 tested host plants from various families.