Ocorrência do crestamento gomoso do caule em melancia no Tocantins causado por Didymella bryoniae

Santos, Gil Rodrigues dos; Filho, Adalberto Corrêa Café

doi:10.1590/s0100-41582006000200017

Cited by 10 publications

(9 citation statements)

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“…Considering that cucurbits have long been cultivated in Brazil, and some of them, such as chayote ( Sechium edule L.) originated in tropical America, variation among populations of D. bryoniae collected from different regions and hosts is expected. Furthermore, the sexual phase of the pathogen has been found occurring naturally in watermelon‐growing areas in Brazil (Santos and Café‐Filho, 2006). The objective of this study was to characterize populations of D. bryoniae from commercial watermelon and other cucurbit hosts from different Brazilian regions on the basis of their biological and molecular diversity.…”

Section: Introductionmentioning

confidence: 99%

Host Specificity and Genetic Diversity of Didymella bryoniae from Cucurbitaceae in Brazil

Santos¹,

Ferreira²,

Pessoa-Filho³

et al. 2009

Journal of Phytopathology

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Thirty-seven isolates of Didymella bryoniae from three Cucurbitaceae species were collected in Brazil and tested for pathogenicity to watermelon. All isolates were pathogenic but differed in aggressiveness levels. Seven representative isolates were used in cross-pathogenicity tests against 10 cucurbitaceous hosts. Most isolates were pathogenic to most host species tested, except to Sechium edule. Among the susceptible species, Citrullus and Cucumis species were the most susceptible hosts, while pumpkin and Luffa purgans were the most resistant. Host of origin affected the pattern of aggressiveness on each host. Isolates from watermelon were very aggressive to their original host, but much less aggressive or not pathogenic at all to some Cucurbita. Two previously described random-amplified polymorphic DNA (RAPD)-specific primers indicated that 81% of the isolates could be classified into the so-called RG I group, while the remaining isolates could not be classified into any of the described RG groups. All 37 isolates were further characterized by RAPD fingerprinting and compared with three US isolates representative of RG I and RG II groups. The Brazilian D. bryoniae isolates could be separated into genetically similar clusters. The majority of the isolates were grouped in cluster DB Ia, which contained only isolates of Citrullus lanatus and Cucumis melo. Two of the American isolates used as controls clustered with this group at 68% similarity level. The DB Ib cluster included three Brazilian isolates obtained from melon and watermelon and the American representative for RG II, at a lower similarity level (43%). Two isolates from watermelon clustered with one isolate from melon in a separate group (DB II), while one single isolate from pumpkin (DB III) showed the lowest genetic similarity to all other isolates. Didymella bryoniae isolates from Brazil showed, therefore, a level of genetic diversity higher than previously reported for the species. RAPD fingerprinting allowed for geographical distinction of D. bryoniae isolates but no correlation between genetic distance, aggressiveness or origin of the isolate was found.

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Section: Introductionmentioning

confidence: 99%

Host Specificity and Genetic Diversity of Didymella bryoniae from Cucurbitaceae in Brazil

Santos¹,

Ferreira²,

Pessoa-Filho³

et al. 2009

Journal of Phytopathology

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“…Given the distances examined (up to 9 m), it is believed that the deposition effects derived from irrigation events governed the dynamics of dispersion and, consequently, disease gradients were well represented by the exponential model. Furthermore, earlier measurements of D. bryoniae isolates found pycniospores and ascospores of average lengths of 11.6 μm and 13.7 μm respectively (Santos and Café-Filho 2006). These spore sizes are within the range given by Fitt and Bainbridge (1984) and Grove et al (1985) for splash-dispersed pathogens better represented by the exponential model, while dispersions of pathogens with spores shorter than 10 μm are usually best described by the power law model.…”

Section: Discussionmentioning

confidence: 52%

“…Although these alloinfections could be the result of airborne inoculum external to the experimental field, we assumed that all or most of these infections are from field-borne ascospores, based on the planting history of the Experimental Station and absence of cucurbit fields in the surrounding area. In addition, GBS is a polycyclic disease and secondary cycles with concurrent formation of pycniospores and ascospores have been noted during the progress of GBS epidemics in commercial watermelon fields in Brazil (Santos and Café-Filho 2006).…”

Section: Discussionmentioning

confidence: 99%

Temporal and spatial dynamics of watermelon gummy stem blight epidemics

2010

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The effect of the distance of initial inoculum on the intensity of watermelon gummy stem blight, caused by Didymella bryoniae, was studied in a naturally-infected rainfed commercial field. The shorter the distance from the focus, the sooner was disease onset and the earlier maximum disease levels were achieved. Maximum disease incidences were reached earlier than maximum severities, but eventually destructive levels were observed for both disease incidence and severity. Disease progressed at similar rates, irrespective of the radial distance from the focus. A detailed study of the disease temporal progress was conducted in inoculated rainfed experimental fields with commercial genotypes Crimson Sweet (susceptible, S) and Riviera (moderately resistant, R). The Gompertz model best described the disease progress curves, and estimated apparent infection rates were 0.049 and 0.020 respectively for S and R genotypes. In addition, spatial pattern studies were conducted during the dry season in overhead irrigated experimental plots, inoculated with point-source foci. Disease intensity gradients were better explained by the Exponential model than by the Power Law model. Gummy stem blight distribution was classified as aggregated by the Ordinary Runs procedure. Two different spatial autocorrelation methods (2DCorr and LCOR) revealed strong short distance spatial dependencies. Long distance positive correlations between quadrats were observed along with periods of higher progress rates. The dynamic patterns of the epidemics of gummy stem blight in watermelon described here are consistent with epidemics of polycyclic diseases with splashdispersed spores.

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“…Phytopathological surveys are very important because they aim to inform about the occurrence and frequency of diseases occurring in a particular crop, thus assisting in proper disease management. Specific surveys of diseases in cucurbits have been performed previously (REIS et al, 2005, Silva et al, 2006CAFÉ FILHO 2006), yet there are few surveys that intended to identify different groups of pathogens in various crops. In the period from 2008 to 2010, Lima and Alves (2011) conducted a nationwide survey of viral diseases in cucurbits, covering 21 municipalities in seven states and the Federal District.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Cucurbit Production Systems and Disease Prevalence in Municipalities in Pernambuco

et al. 2016

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-Cucurbits have great economic, nutritional and social importance in the Brazilian semiarid region. In this region, many factors can result in reduced productivity of these crops, especially fungal and viral diseases. Therefore, knowledge of cucurbits is crucial for proper disease management. The objective of this work was to identify the major diseases of cucurbits grown in some municipalities in the Hinterland of the state of Pernambuco. Thus, plant samples were collected with symptoms in crops in the municipalities of Salgueiro, Serra Talhada, Floresta, Petrolândia, Ibimirim, Custódia and Inajá. A questionnaire was also applied to gather information about the production profile of producers. Seven fungal pathogens infecting cucurbits were identified: Pseudoperonospora cubensis, Colletotrichum sp., Podosphaera xanthii, Rhizoctonia solani, Didymella bryoniae, Fusarium sp. e Alternaria sp., and three viruses as well: Papaya ringspot viruswatermelon strain (PRSV-W), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV). It was found that in small crops, there is limited search for technical information om cropping, and these crops originate mostly from native seeds, in contrast to medium and large producers, who use improved cultivars. The melon and watermelon crops are the most commercially exploited, while pumpkins are used in subsistence agriculture. As for plant health problems, most respondents reported knowing the main diseases that occur in crops and perform disease control based on personal experience and / or through the help of the technical assistance provided by agricultural stores. In a few cases, in large farms, there was an agronomist to assist in this type of control.Keywords: Plant pathology survey. Citrullus. Cucurbita. Cucumis. Fungi. Viruses. CARACTERIZAÇÃO DOS SISTEMAS DE PRODUÇÃO DE CUCURBITÁCEAS E DA PREVALÊNCIA DE DOENÇAS EM MUNICÍPIOS PERNAMBUCANOSRESUMO -As cucurbitáceas possuem grande importância econômica, nutricional e social no Semiárido brasileiro. Nesta região, diversos fatores podem acarretar em redução na produtividade dessas culturas, destacando-se as doenças fúngicas e viróticas, tornando-se necessário o conhecimento das mesmas para um adequado manejo. Assim, o objetivo desse trabalho foi identificar as principais doenças de cucurbitáceas produzidas em alguns municípios localizados no Sertão Pernambucano. Para tanto, foram coletadas amostras de plantas com sintomas em cultivos nos municípios de Salgueiro, Serra Talhada, Floresta, Petrolândia, Ibimirim, Custódia e Inajá. Também foi aplicado um questionário visando obter informações do perfil produtivo dos produtores. Identificou-se sete patógenos fúngicos infectando cucurbitáceas, Pseudoperonospora cubensis, Colletotrichum sp., Podosphaera xanthii, Rhizoctonia solani, Didymella bryoniae, Fusarium sp. e Alternaria sp., e três vírus, Papaya ringspot virus type watermelon (PRSV-W), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV). Verificou-se que nos pequenos cultivos, a busca por informaçõe...

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Ocorrência do crestamento gomoso do caule em melancia no Tocantins causado por Didymella bryoniae

Cited by 10 publications

References 0 publications

Host Specificity and Genetic Diversity of Didymella bryoniae from Cucurbitaceae in Brazil

Host Specificity and Genetic Diversity of Didymella bryoniae from Cucurbitaceae in Brazil

Temporal and spatial dynamics of watermelon gummy stem blight epidemics

Characterization of Cucurbit Production Systems and Disease Prevalence in Municipalities in Pernambuco

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