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1.
Red rot caused by Colletotrichum falcatum is one of the most devastating fungal diseases of sugarcane in many tropical countries. In this study, the efficacy of various resistance-inducing agents was evaluated against red rot at two growth phases of sugarcane, i.e., the germination and grand growth phases, for four consecutive cropping seasons (2011–12 to 2014–15) under field conditions. Inducer candidates of both synthetic origin (benzothiadiazole [BTH], salicylic acid [SA], potassium silicate [PSi]) and biotic origin (Colletotrichum falcatum [Cf] elicitor and Reynoutria sachalinensis extract) were evaluated for their efficacy on a red rot susceptible sugarcane cultivar CoC 671. Inducer concentrations that showed significant reduction of red rot lesion length in leaf bioassays without exhibiting direct antifungal activity were used in the field trials. Overall, results of the four field trials indicated that application of BTH (125 μM) and Cf elicitor (60 μg glucose equivalent/ml) were most efficient in reducing disease incidence during the germination and establishment phases against soil-borne inoculum and suppressed disease severity in pathogen challenged cane stalks during the grand growth phase. In addition, other treatments also had significant effects on germination and stalk disease severity. Quantification of C. falcatum biomass in resistance inducer-treated canes by quantitative PCR (qPCR) substantiated the disease suppressive effect of BTH and Cf elicitor. Whereas all resistance inducers significantly increased the cane weight, only BTH and PSi significantly increased the juice quantity. Other juice quality parameters were generally not affected by the inducers.  相似文献   

2.
Red rot is an important disease of sugarcane, reported from the main producing countries of the crop. The main causal agent is Colletotrichum falcatum, which induces reddish internal stalk rot, resulting in loss of quality and quantity of sugars. While the occurrence of this disease has been reported in plantations in Brazil, the aetiology of the disease is not yet fully understood. We isolated and identified the fungi associated with sugarcane plants showing symptoms of red rot. Thirty isolates were recovered and grouped by morphology within the genera Colletotrichum and Fusarium. Based on phylogenetic analyses of DNA sequences from ITS, ACT, SOD, GAPDH, and EF-, eight isolates were identified as C. falcatum (n = 6) and C. plurivorum (n = 2). Twenty-two isolates belonged to the Fusarium fujikuroi species complex and were identified as F. sacchari (n = 8), F. proliferatum (n = 3), and F. madaense (n = 11). Coinfection with C. falcatum and Fusarium species were frequently observed. C. falcatum and Fusarium strains induced reddening of internal tissues and stalk rot in sugarcane plants, symptoms of red rot, while Fusarium species also induced symptoms of pokkah boeng. C. plurivorum, whose sexual stage was observed on the surface of stems, did not induce stalk rot or leaf symptoms. The results obtained in this study clarify the aetiological agents of red rot of sugarcane in Brazil. The conditions that lead to the development of specific symptoms of red rot or pokkah boeng are under investigation.  相似文献   

3.
BACKGROUND: Rhizobacteria have a good potential to suppress soilborne diseases, but their efficacy against sugarcane pests is rarely reported. Bacterial strains isolated from the rhizosphere of sugarcane were evaluated for their potential to suppress red rot disease on two susceptible varieties, Co‐1148 and SPF‐234, under field conditions. The strains were also characterised for the production of secondary metabolites associated with their antagonistic activity. RESULTS: One out of four strains, the Pseudomonas putida strain NH‐50 (EU627168), reduced disease severity by 44–60% in different field trials. This potent antagonistic strain produced pyoluteorin antibiotic, as confirmed by high‐performance liquid chromatography (HPLC). The PltB gene involved in pyoluteorin synthesis was amplified from the P. putida strain NH‐50 and sequenced. The extracellular metabolites and volatile and diffusible antibiotics secreted by the tested strains inhibited mycelial growth of Glomerella tucumensis (Speg.) Arx & E Mull in vitro by 7–55%. CONCLUSION: The pyoluteorin‐producing bacteria P. putida strain NH‐50 significantly reduced disease severity on both sugarcane varieties, irrespective of fungal inoculation, i.e. either inoculated through stem or through soil. This strain also possesses other plant growth characteristics and can be used as a biopesticide for sugarcane crop. Copyright © 2011 Society of Chemical Industry  相似文献   

4.
Brazil is the world’s biggest producer of sugarcane (Saccharum spp. hybrids). Pokkah boeng is an important fungal disease in this crop caused by members of the Fusarium fujikuroi species complex (FFSC) and characterized by deformation of the aerial part of the plant and stem rot. While the occurrence of symptoms has been reported in plantations in Brazil, no official reports of the disease exist. In this study, species of the FFSC were identified that are associated with sugarcane plants with symptoms of pokkah boeng in Brazil. This was achieved using two-loci molecular phylogeny, sexual compatibility and analysis of morphological markers. The ability of strains to cause disease in plants of sugarcane, maize, sorghum and millet was also evaluated. The 39 isolates studied were identified as F. sacchari, F. proliferatum and another, still unknown, phylogenetic lineage that is sister to F. andiyazi. Crossing field isolates of F. sacchari and F. proliferatum with their respective tester strains produced fertile perithecia and viable ascospores. All three species induced symptoms of pokkah boeng on inoculated sugarcane plants and caused stem rot in maize, sorghum and millet. Symptoms on sugarcane are chlorosis and necrosis of leaves, punctured lesions, twisted leaves, reduction of the total leaf area, death of the top of the plant and stalk rot. The findings confirmed the aetiology of the disease in Brazil, generated basic knowledge for the development of strategies for diagnosis and monitoring of the disease and support breeding programmes for selecting resistant germplasm.  相似文献   

5.
The effect of a novel synthetic signal molecule, acibenzolar-S-methyl (CGA-245704; benzo [1,2,3] thiadiazole-7-carbothioic acid S-methyl ester), in inducing resistance in sugarcane against red rot disease caused by the fungusColletotrichum falcatum Went was studied. Application of CGA-245704 as a soil drench or along with marcotting rooting mixture induced resistance in sugarcane to challenge inoculation withC. falcatum. When the pathogen was inoculated by the plug method, it caused discoloration in the untreated control stalk tissues; however, in the stalk tissues pretreated with acibenzolar-S-methyl, pathogen colonization was considerably reduced. When the pathogen was inoculated by nodal swabbing, its penetration was arrested in the sensitized stalk tissues. An induced systemic resistance effect was found to persist up to 30 days in the pretreated cut canes. Increased phenolic content and accumulation of pathogenesis-related (PR) proteins,viz., chitinase, β-1,3-glucanase and thaumatin-like protein (PR-5), were observed in sugarcane plants treated with acibenzolar-S-methyl.  相似文献   

6.
Red stripe caused by the bacterium Acidovorax avenae subsp. avenae (Aaa) is a disease of sugarcane that is distributed worldwide. In this study, 108 sugarcane leaf samples were collected in 2013–2016 from nine sugarcane‐growing regions in China. Aaa was detected by PCR with specific and novel primers from the 16S–23S rDNA internal transcribed spacer region in 81 of 84 (96%) leaves with red stripe symptoms and in 20 of 24 (83%) leaves without symptoms. Furthermore, Aaa was detected in all nine sampling locations representing six sugarcane‐producing provinces in China. The 101 amplified fragments were cloned and sequenced. The size of the nucleotide sequences varied from 436 to 454 bp and the sequence identity ranged from 89.2% to 100%, suggesting a significant genetic variation among Aaa strains from China. Five major restriction fragment length polymorphism (RFLP) profiles were obtained by in silico and polyacrylamide gel electrophoresis analyses of the PCR products digested with HindIII and EcoRI. The causal agent of sugarcane red stripe was also successfully isolated from a diseased plant and its pathogenicity confirmed by inoculation of healthy sugarcane plantlets and reproduction of disease symptoms. The data showed that Aaa is currently widespread in China, suggesting that control methods should be implemented to limit the impact of red stripe on sugarcane production.  相似文献   

7.
ABSTRACT Six herbicides were evaluated for their effects on Pythium root rot and growth of sugarcane in greenhouse experiments and on in vitro mycelial growth rate of Pythium arrhenomanes. Pendimethalin and atrazine were most inhibitory to mycelial growth, but neither reduced root rot severity. Asulam, atrazine, and metribuzin were not phytotoxic to sugarcane and did not affect root rot symptom severity in clay loam or silt loam field soils. Atrazine and metribuzin increased shoot number, and atrazine increased total shoot weight for treated plants in silt loam soil. Glyphosate, pendimethalin, and terbacil were phytotoxic to sugarcane. These herbicides increased root rot severity, but the extent to which growth reductions resulted from increased disease severity or from direct herbicide injury was not clear. Adverse effects on plant growth and root rot severity were greater in clay loam than in silt loam soil. The results suggest that sugarcane injury from some herbicides is compounded by increased severity of root rot.  相似文献   

8.
Abstract

Charcoal rot caused by Macrophomina phaseolina (Deuteromycetes: Coelomycetes) is found throughout the tropics and subtropics and has a wide host range. Together with most of the legume crops, the common bean (Phaseolus vulgaris) Is a good host for the fungus which causes a range of symptoms, depending on environmental conditions and age of the plant. In addition to charcoal rot, which is a stem or stalk rot disease, the pathogen also causes damping‐off and seedling blight in beans. Charcoal rot in the mature plant is associated with senescence which is accelerated by water stress. The disease is most damaging in areas of unreliable rainfall and high temperature. In Kenya, beans are usually grown in mixed stands with maize, sorghum or millet. Population pressure has led to the cultivation of beans on land prone to drought. M. phaseolina is one of the most important pathogens affecting all the main crops of the farming systems in the semi‐arid areas of eastern Kenya and resistance to charcoal rot is a priority if beans are to be increasingly grown in these areas. The paper reviews the literature on charcoal rot of beans and on other crops where similar work has not been reported specifically for beans.  相似文献   

9.
J. M. DUNCAN 《EPPO Bulletin》1990,20(1):107-115
Phytophthora frugariae causes red core root rot of strawberries. Although the disease is probably most acute in northern Europe, serious outbreaks have been reported from a number of Mediterranean countries, especially France and Italy. Leather rot of fruit and crown rot, which are caused by P. cuctorum, can also be severe problems in warmer climates. Both fungi survive in soil for long periods, but the most common form of spread is in diseased planting material. Sensitive tests have been developed to detect red core in planting material, and been used to effect in certification schemes. Root rot of raspberry has gained prominence in the last 10 years in Europe as raspberry growing has expanded, but the disease has been known for many years in France. Nine species of Phyfophthora have been recovered from affected plants, but two of these, one with affinities with P. megasperma, and P. cumbiuora, are responsible for most major outbreaks. The other species are only troublesome where drainage is poor. Again, spread is mainly in infected material. Few raspberries are resistant to root rot, but some wild RubuP spp., blackberries and raspberry x blackberry hybrids are resistant and may be useful in breeding programmes.  相似文献   

10.
Red stripe is a bacterial disease of sugarcane causing important economic losses in Argentina that affects 30 % of the milling stems and consequently the juice quality. In this study, sugarcane leaves exhibiting red stripe symptoms were sampled in the 2008–09 growing season from 13 different sugarcane producing areas of Tucumán and Salta (northwest of Argentina). To achieve the identification and characterization of the causal agent of red stripe, bacterial isolation was performed. Species-specific PCR using Oaf1/Oar1 primers allowed the amplification of a fragment of 550 bp from approximately 50 % of the isolates; 16S rDNA sequences analysis displayed a similarity greater than 99 % with Acidovorax avenae subsp. avenae. By means of RAPD-PCR the presence of at least four different biotypes among the analyzed isolates was detected. Results of pathogenicity test allowed us to confirm A. avenae subsp. avenae as the pathogenic agent for red stripe. This study constitutes the first report on the identification and molecular characterization of this plant pathogen from the Argentina sugarcane production areas. The genetic diversity observed among A. avenae is an important factor to be considered to improve an accurate diagnosis and/or the selection of sugarcane tolerant clones.  相似文献   

11.
 在广西博白县发现一种国内外尚未报道的新病害-甘蔗心腐病。根据对病原细菌的个体形态、培养性状、生理生化反应及其对菠萝果实的致病性等方面的试验研究结果,鉴定甘蔗心腐病病原细菌为菠萝欧文氏杆菌(Erwinia ananas Serrano)。  相似文献   

12.
杨梅白腐病是影响杨梅产量和品质的一个重要因素,研究该病害的防治技术,对于保障杨梅生产安全、增加农民收入具有重要意义。本文通过田间试验评价了7种药剂对杨梅白腐病的预防效果,结果表明,供试药剂对白腐病均有一定的防效。其中,6%寡糖·链蛋白WP、8%对氯苯氧乙酸钠SP和29%吡萘·嘧菌酯SC对白腐病的预防效果在80%以上;40%戊唑·腐霉利SC、38%吡唑·啶酰菌胺SC和35%氟菌·戊唑醇SC的预防效果在杨梅成熟前期较好,能达到80%以上,但持效性不长;13.3%抑霉唑硫酸盐SG的预防效果不佳,在杨梅成熟期阶段最高防效只有65.5%。建议在实际生产中预防杨梅白腐病选用6%寡糖·链蛋白WP、8%对氯苯氧乙酸钠SP和29%吡萘·嘧菌酯SC。平衡施肥、避雨栽培、疏花疏果和药剂防治相结合的综合防控技术可有效降低白腐病的发生危害。  相似文献   

13.
Abstract

Thirty two diseases and disorders affecting the oil palm in Africa, Southeast Asia and South America are described with their distribution, economic importance, etiology and control. Of these, nine diseases are considered to be of major economic importance, 19 are of minor importance, and four are due to nutrient deficiencies. The major diseases causing serious economic losses are freckle (Cercospora elaeidis), blast (Pythium splendens and Rhizoctonia lamellifera), vascular wilt (Fusarium oxysporum f. sp. elaeidis). Ganoderma trunk rot (Ganoderma spp.) and Armillaria trunk rot (Armillariella mellea) in Africa; Ganoderma trunk rot, Corticium leaf rot (Corticium solani). Marasmius bunch rot (Marasmius palmivora) in S.E. Asia; sudden wilt and spear rot in S. America. Some of the diseases and disorders of minor economic importance recorded in these areas are anthracnose (Botryodiplodia palmarum, Melanconium sp. and Clomerella cingulata), dry basal rot (Ceratocystis paradoxic), patch yellows (Fusarium oxysporum), crown disease, Cylindrocladium leaf spot (Cylindrocladium macrosporum), algal spot (Cephaleuros virescens), bronze streak, ring spot and little leaf in Africa; Curvularia leaf blight (Curvularia eragrostidis), Leptosphaeria leaf spot (Pestalotiopsis spp.) infectious chlorosis, upper stem rot (Phellinus noxius), stem wet rot, charcoal base rot in S.E. Asia and Leptosphaeria leaf spot and coconut wilt disease in S. America. Little is known, however, about the disease problems in the smaller but rapidly expanding oil palm growing areas of Thailand, Papua New Guinea, India and Sri Lanka. Infectious chlorosis, bronze streak and ring spot have a suspected virus etiology; little leaf, spear rot and stem wet rot are attributed to bacteria and leaf chlorosis, mid-crown yellowing, orange frond and hook leaf to nutrient deficiencies. The etiology of some minor disorders including brown germ, crown disease and several miscellaneous abnormalities is unknown.

Effective control measures, based on the application of various chemicals, have been devised for the leaf diseases but other than precautionary cultural operations, there are no such effective and practical control measures for the root and stem diseases. For this latter group of diseases field transplanting or resistant or tolerant varieties seems to be the best method of control. Seeds selected for tolerance to vascular wilt are being produced on a commercial scale at the Nigerian Institute for Oil Palm Research, Institut de Recherches pour les Huiles et Oleagineux in Ivory Coast and the Unilever Plantations in Cameroun Republic. These efforts need to be supplemented by breeding for resistance to the other major diseases.  相似文献   

14.
Abstract

The recent spread of coffee rust, sugarcane rust, black leaf streak of banana and Alternaria blight of wheat are recorded and the implications of new disease records are discussed.  相似文献   

15.
江西甘蔗花叶病田间调查   总被引:1,自引:0,他引:1  
2007年9-10月对江西甘蔗花叶病(sugarcane mosaic disease)进行了多点田间调查,结果表明江西甘蔗普遍发生花叶病,其中红皮甘蔗花叶病重于青皮甘蔗,两者病丛率分别为59.8%和19.2%,赣北、赣中、赣南3大地区之间的甘蔗花叶病发生轻重无明显差异。  相似文献   

16.
Journal of Plant Diseases and Protection - Red rot of sugarcane caused by the fungus Colletotrichum falcatum Went is the most destructive and severe disease worldwide. The present study identifies...  相似文献   

17.
Epidemiology of Fusarium Diseases and their Mycotoxins in Maize Ears   总被引:1,自引:0,他引:1  
Fusarium species cause two distinct diseases on ears of maize, Fusarium ear rot (or pink ear rot) and Gibberella ear rot (or red ear rot), both of which can result in mycotoxin contamination of maize grain. The primary causal agent for Fusarium ear rot is Fusarium verticillioides, but F. subglutinans and F. proliferatum are also important. Gibberella ear rot is caused primarily by F. graminearum, but F. culmorum can also be important, especially in Europe. Aspects of the epidemiology of both diseases have been studied for decades, but only recently have efforts been made to synthesize this information into comprehensive models of disease development. Much of the work on F. graminearum has focused on Fusarium head blight of small-grain crops, but some of the results obtained are also relevant to maize. The primary mycotoxins produced by these fungi, fumonisins and deoxynivalenol, have differing roles in the disease-cycle, and these roles are not completely understood, especially in the case of fumonisins. Progress is being made toward accurate models for risk assessment of both diseases, but key challenges remain in terms of integrating models of pre- and post-infection events, quantifying the roles of insects in these diseases, and characterizing interactions among competing fungi and the environment.  相似文献   

18.
Light represents a signal for the regulation of virulence in many microbial pathogens. Two stone fruits, nectarines and cherries, were used to investigate the influence of light on brown rot caused by Monilinia laxa. Three single-spore isolates were inoculated on nectarines and incubated under different white lights, red light, blue light, green light, and black light with two photoperiods. In addition, to understand the effect of daylight irradiance on brown rot, M. laxa was inoculated on different cherry cultivars and incubated under two simulated solar irradiations. Significantly higher disease severity and sporulation were reported on inoculated nectarines incubated under 58 W white light for 12 hr light/12 hr darkness than on nectarines incubated in continuous darkness. Only red light caused a significant increase in the incidence and severity of the disease in nectarines inoculated with the three M. laxa isolates, compared to fruit incubated under white light. High light intensity (185.45 W/m2), caused greater brown rot severity in all cherry cultivars, both early and late varieties, than low irradiance (145.85 W/m2). Significant up-regulation of the pathogenicity-related MlPNL2 gene was observed as an early response after cherry inoculation under high-intensity light, especially in late cherry cultivars, while MlPG1 expression did not show any changes under different light irradiances. M. laxa was shown to be a light-responsive fungal pathogen, and light seemed to play an active role in brown rot development.  相似文献   

19.
Fusarium species involved in the Fusarium crown rot (FCR) complex affect wheat in every stage of development from seedling to grain fill. This study was designed to compare the aggressiveness of the FCR complex members including F. culmorum, F. pseudograminearum and F. graminearum in causing seedling blight, decreased plant vigour and crown rot. To assess their relative pathogenicity, two hard red spring wheat cultivars and two durum wheat cultivars were inoculated in the field with five isolates from each of the three species for two years. Significant differences in patterns of pathogenicity were identified. In particular, F. culmorum caused greater seedling blight while F. pseudograminearum and F. graminearum caused greater crown rot. Greatest yield reductions were caused by F. pseudograminearum. Cultivar differences were identified with respect to seedling disease and late season crown rot. No interactions were identified between cultivar performance and isolates or species with which they were challenged.  相似文献   

20.
我国对草莓炭疽根腐病的重视程度亟待提高   总被引:5,自引:0,他引:5  
张国珍 《植物保护》2015,41(2):234-236
草莓炭疽根腐病是近年来发生较为普遍和严重的草莓病害,但对该病害的认识不足甚至存在误区。本文介绍了草莓炭疽根腐病与草莓红中柱根腐病在症状表现、病原菌种类及用药策略上的不同,并指出了国内草莓炭疽病发生和危害的特点,勿将炭疽根腐病误认为是红中柱根腐病。  相似文献   

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