Novel Pathotypes of Elsinoe australis Associated with Citrus australasica and Simmondsia chinensis in Australia

Molecular phylogenetic analysis, morphology and pathogenicity to citrus fruit were used to study two isolates of Elsinoe australis associated with scab-like symptoms on a fruit of Citrus australasica (finger lime) and Simmondsia chinensis (jojoba) in Australia. In addition to being associated with finger lime, the isolate from finger lime could cause scab symptoms on C. x aurantium cv. Murcott tangor in pathogenicity tests, but could not cause scab symptoms on the other orange, mandarin, lemon or grapefruit tested. Pathogenicity tests also support previous studies showing the isolate from jojoba could not produce symptoms on fruit of C. natsudaidai. Based on the findings of this study, two novel pathotypes of E. australis are designated from Australia; namely the Finger Lime (FL) pathotype associated with finger lime, and the Jojoba Black Scab (JBS) pathotype associated with black scab of jojoba. The significance of these novel E. australis pathotypes on market access and biosecurity issues for citrus are briefly discussed.

Reaction of tangerines genotypes to Elsinoe fawcettii under natural infection conditions

A verrugose dos citros, causada pelo fungo Elsinoe fawcettii, encontra-se presente em todas as áreas citrícolas do Brasil. Dada sua importância, o comportamento de acessos e híbridos de tangerinas foi avaliado sob condições naturais de infecção. O estudo envolveu plantas não irrigadas, com 15 anos de cultivo, sendo coletados 100 frutos de três plantas por genótipo, na fase de colheita. Mediante o emprego de escala de notas que variaram de 0 (ausência de sintomas) a 6 (sintomas severos), procedeu-se a avaliação do nível de severidade da doença. Dentre genótipos que mostraram-se resistentes incluem-se Citrus deliciosa, C. tangerina, C. nobilis; um híbrido de mandarina (C. nobilis x C. deliciosa) e um híbrido de satsuma (C. unshiu x C. sinensis). Nos demais genótipos foram encontrados sintomas, cujos níveis de severidade variaram de 1 a 3, enquadrando-os como de moderada resistência.

Reação de genótipos de tangerinas a Alternaria alternata e Elsinoe fawcettii: resistência, suscetibilidade e acúmulo de metabólitos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Elsinoe australis; Myriangiaceae

Elsinoe australis Bitanc. & Jenkins

Atividade fungitóxica de produtos alternativos sobre Elsinoe ampelina.

2011

Doenças de citros no Estado do Amazonas.

Informacoes sobre as principais doencas que atacam os citros no Amazonas, com descricoes dos sintomas e controle.

Efficacy of pre- and postinoculation application of Fungicides to expanding young citrus leaves for control of melanose, scab, and alternarial brown spot

In greenhouse trials, copper hydroxide, pyraclostrobin, and famoxadone were applied to actively crowing young citrus seedlings to determine the duration of protection of young leaves provided by these fungicides against melanose, caused by Diaporthe citri, citrus scab, caused by Elsinoe fawcettii, and Alternaria brown spot, caused by Alternaria alternata. Fungicides were applied to different sets of potted plants of grapefruit for control of melanose, of rough lemon for control of scab, and of Dancy tangerine for control of Afternaria brown spot 1 to 6 days prior to inoculation. as well as on the day of inoculation. Leaf area of treated shoots was estimated on the day of fungicide application and the day of inoculation and disease severity evaluated subsequently. In most cases. copper hydroxide and famoxadone provided at least 50% control of all three diseases for only about 2 days after application. Generally, there was little or no disease control when the products were applied 4 or more days before inoculation. In contrast, pyraclostrobin usually provided a high level of control of all three diseases when applied up to 5 days prior to inoculation. The level of disease control decreased as the interval between a fungicide application and inoculation increased and the relationship between disease control and leaf expansion best fit a quadratic equation. Effective disease control was observed with copper hydroxide and famoxadone until leaf area had increased by 100 to 200%, whereas control with pyraclostrobin was observed up to 400 to 500% increase in leaf area. In postinoculation tests with scab and melanose, pyraclostrobin provided high levels of disease control (>75%) when applied up to 2 days after inoculation. whereas copper hydroxide and famoxadone had minimal postinoculation activity. Applications of pyraclostrobin to the spring flush growth of citrus trees are much more likely to provide control of melanose, scab, and Alternaria brown spot than those of famoxadone or copper hydroxide.

Produtos alternativos com atividade fungitóxica sobre patógenos da videira para quebra da dormência de gemas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos de produtos alternativos no controle de doenças na videira

Pós-graduação em Agronomia - FEIS

Danos prolongados.

Com ataque a todos os tecidos verdes e jovens da videira, o fungo Elsinoe ampelina, causador da antracnose da videira, além de ocasionar perdas que podem chegar a 100% da produção, afeta toda a parte aérea da planta e compromete o seu desenvolvimento nos anos seguintes. De difícil controle, a recomendação é de que se devem adotar medidas preventivas desde a implantação da cultura, começando pela escolha do local de plantio.