Comportamento sazonal da clorose variegada dos citros em três regiões do Estado de São Paulo

Laranjeira, F. F.; Filho, Armando Bergamin; Amorim, Lílian; Lopes, João Roberto Spotti

doi:10.1590/s0100-41582003000600009

Cited by 9 publications

(9 citation statements)

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“…The acyl-homoserine lactones (acyl-HSLs) produced by Methylobacterium mesophilicum isolated from orange trees infected with the citrus variegated chlorosis (CVC) disease have been studied, revealing the occurrence of six longchain acyl-HSLs, i.e., the saturated homologues (S)-N-dodecanoyl (1) and (S)-N-tetradecanoyl-HSL (5), the uncommon odd-chain N-tridecanoyl-HSL (3), the new natural product (S)-N-(2E)-dodecenoyl-HSL (2), and the rare unsaturated homologues (S)-N-(7Z)-tetradecenoyl ( 4) and (S)-N-(2E,7Z)-tetradecadienyl-HSL (6). The absolute configurations of all HSLs were determined as 3S.…”

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confidence: 99%

Long-Chain Acyl-Homoserine Lactones from Methylobacterium mesophilicum: Synthesis and Absolute Configuration

et al. 2009

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The acyl-homoserine lactones (acyl-HSLs) produced by Methylobacterium mesophilicum isolated from orange trees infected with the citrus variegated chlorosis (CVC) disease have been studied, revealing the occurrence of six long-chain acyl-HSLs, i.e., the saturated homologues (S)-N-dodecanoyl (1) and (S)-N-tetradecanoyl-HSL (5), the uncommon odd-chain N-tridecanoyl-HSL (3), the new natural product (S)-N-(2E)-dodecenoyl-HSL (2), and the rare unsaturated homologues (S)-N-(7Z)-tetradecenoyl (4) and (S)-N-(2E,7Z)-tetradecadienyl-HSL (6). The absolute configurations of all HSLs were determined as 3S. Compounds 2 and 6 were synthesized for the first time. Antimicrobial assays with synthetic acyl-HSLs against Gram-positive bacterial endophytes co-isolated with M. mesophilicum from CVC-infected trees revealed low or no antibacterial activity.

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confidence: 99%

Long-Chain Acyl-Homoserine Lactones from Methylobacterium mesophilicum: Synthesis and Absolute Configuration

et al. 2009

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“…Although work on plants is not subject to the ethical concerns that hamper experimentation targeting pathogens of animal or human hosts, mathematical modelling nevertheless becomes particularly compelling for plant diseases when logistic constraints mean that experimentation would be costly or difficult. This situation is exemplified by diseases caused by pathogens with epidemiology necessitating long experiments to yield useful data [11] – [13] , pathogens causing symptoms that are difficult to detect [14] , [15] , pathogens with epidemiology that is ill-understood [16] , [17] , and/or pathogens that would require experimental trials in the vicinity of susceptible commercial growing operations [18] , [19] .…”

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Cost-Effective Control of Plant Disease When Epidemiological Knowledge Is Incomplete: Modelling Bahia Bark Scaling of Citrus

et al. 2014

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A spatially-explicit, stochastic model is developed for Bahia bark scaling, a threat to citrus production in north-eastern Brazil, and is used to assess epidemiological principles underlying the cost-effectiveness of disease control strategies. The model is fitted via Markov chain Monte Carlo with data augmentation to snapshots of disease spread derived from a previously-reported multi-year experiment. Goodness-of-fit tests strongly supported the fit of the model, even though the detailed etiology of the disease is unknown and was not explicitly included in the model. Key epidemiological parameters including the infection rate, incubation period and scale of dispersal are estimated from the spread data. This allows us to scale-up the experimental results to predict the effect of the level of initial inoculum on disease progression in a typically-sized citrus grove. The efficacies of two cultural control measures are assessed: altering the spacing of host plants, and roguing symptomatic trees. Reducing planting density can slow disease spread significantly if the distance between hosts is sufficiently large. However, low density groves have fewer plants per hectare. The optimum density of productive plants is therefore recovered at an intermediate host spacing. Roguing, even when detection of symptomatic plants is imperfect, can lead to very effective control. However, scouting for disease symptoms incurs a cost. We use the model to balance the cost of scouting against the number of plants lost to disease, and show how to determine a roguing schedule that optimises profit. The trade-offs underlying the two optima we identify—the optimal host spacing and the optimal roguing schedule—are applicable to many pathosystems. Our work demonstrates how a carefully parameterised mathematical model can be used to find these optima. It also illustrates how mathematical models can be used in even this most challenging of situations in which the underlying epidemiology is ill-understood.

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“…Tais fatos indicam que existe relação entre o período de incubação e o desenvolvimento das plantas em condições de campo, o que, conseqüentemente, interfere no aparecimento de sintomas (Palazzo & Carvalho, 1992;Laranjeira et al, 2003). Além disso, o verão é a estação do ano em que a população de cigarrinhas se mostra mais numerosa (Lopes, 1999).…”

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Reação de variedades e clones de laranjas a Xylella fastidiosa

et al. 2006

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, LUIZ CARLOS DONADIO 8 RESUMO -A clorose variegada dos citros (CVC) é uma doença grave, causada por Xylella fastidiosa. As medidas usuais de controle mostram-se pouco eficientes ou práticas e com alto custo. Dessa forma, o uso de variedades resistentes e/ou tolerantes desponta como a alternativa mais eficiente, razão pela qual se julgou oportuna a realização deste trabalho. O presente estudo teve como objetivo avaliar o comportamento de variedades e clones de laranjas introduzidas em relação a X. fastidiosa. Foram estudados 59 variedades e clones de laranjas doces e 2 de laranjas azedas introduzidos da França, Itália e Portugal. O delineamento experimental foi o de blocos casualizados (DBC), com 62 tratamentos e 4 repetições, incluindo a variedade 'Pêra', como padrão. Cada parcela continha duas plantas, sendo uma inoculada e a outra sem inoculação. Para a inoculação do patógeno, foi empregado o método de encostia, utilizando-se de mudas infectadas. Para a avaliação da incidência da doença, utilizou-se de dados qualitativos, positivos ou negativos, enquanto para severidade empregou-se escala de notas, que foi estabelecida baseando-se nos sintomas de CVC, confirmados através dos testes de PCR. As variedades de laranjas azedas Beja e Sr. Pinto e as laranjas doces Navelina ISA 315, Navelina SRA 332 e Newhall Navel SRA 343 não apresentaram sintomas em folhas até 27 meses após a inoculação. Termos de indexação: citros, CVC, bactéria, tolerância, doença. REACTION OF ORANGES VARIETIES AND CLONES TO Xylella fastidiosaABSTRACT -Citrus variegated chlorosis (CVC) is a serious disease, caused by Xylella fastidiosa, being the most important to the Brazilian citriculture. The usual measures of control show less efficient or practice and they are very expensive. The use of resistant varieties is showed as the most efficient, consisting the aimed of this research. The objective of the present work was study the behavior of varieties and clones introduced in relation to X. fastidiosa. Were studied 59 varieties and clones of sweet oranges and 2 sour oranges introduced from France, Italy and Portugal. The experimental layout was a complete randomized block design, with 4 replicates and 62 treatments, with 'Pêra' variety as control. Each treatment had two plants, one inoculated and the other without inoculation. For the pathogen inoculation was used the grafting approach with infected seedlings. For the disease incidence measurement was used qualitative data, positive or negative, while for the severity it, was used a note scale based on CVC symptoms confirmed through the PCR tests. The sour oranges varieties Beja and Sr. Pinto and the sweet oranges Navelina ISA 315, Navelina SRA 332 e Newhall Navel SRA 343, have not presented leaves symptoms until 27 months after inoculation.

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Comportamento sazonal da clorose variegada dos citros em três regiões do Estado de São Paulo

Cited by 9 publications

References 5 publications

Long-Chain Acyl-Homoserine Lactones from Methylobacterium mesophilicum: Synthesis and Absolute Configuration

Long-Chain Acyl-Homoserine Lactones from Methylobacterium mesophilicum: Synthesis and Absolute Configuration

Cost-Effective Control of Plant Disease When Epidemiological Knowledge Is Incomplete: Modelling Bahia Bark Scaling of Citrus

Reação de variedades e clones de laranjas a Xylella fastidiosa

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