Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Virulence and impact of brazilian strains of Puccinia psidii on hawaiian ‘Ōhi‘a (Metrosideros polymorpha)(Pacific Science, 2014-01) Silva, André Costa da; Andrade, Pedro Magno Teixeira de; Alfenas, Acelino Couto; Graça, Rodrigo Neves; Cannon, Phil; Hauff, Rob; Ferreira, Diego Cristiano; Mori, SylviaA single strain of Puccinia psidii, the causal agent of rust disease on Myrtaceae, was recently reported on multiple myrtaceous hosts in Hawai‘i, but this strain has caused only mild levels of damage to the state’s predominantn ative forest tree, ‘öhi‘a ( etrosideros polymorpha). Multiple other strains of Puc Mcinia psidii have been identified from Brazil and characterized via extensive sampling and microsatellite analyses. Potential effects of other Brazilian P. psidii strains on Hawai‘i’s ‘öhi‘a were investigated with two inoculation experiments conducted in Brazil. The first, a split-plot experiment, was conducted to deter- mine pathological impact of five Brazilian P. psidii strains on ‘öhi‘a seedlings and to assess variation in susceptibility of seedlings from six different open- ollinatedp ‘öhi‘a parent trees to each P. psidii strain. The second experiment was conducted to determine influence of the rust disease on growth and survival of ‘öhi‘a seedlings. Three of the five P. psidii strains were highly virulent on most of the inoculated ‘öhi‘a seedlings (93% 00% infection rates), and none of the ‘öhi‘a–1 families used in this test showed significant resistance. The other two strains tested were much less virulent. Infection by the highly virulent strains of P. psidii resulted, on average, in a 69% reduction in height growth and 27% increase in mortality of ‘öhi‘a seedlings at 6 months postinfection. These results have immediate implications for designing Hawai‘i’s quarantine barriers.Item Eficiência de fungicidas sistêmicos no controle da ferrugem do Eucalyptus(Revista Árvore, 2008-08-22) Zauza, Edival Ângelo Valverde; Couto, Michele Margarido Fonseca; Maffia, Luiz Ântonio; Alfenas, Acelino CoutoAvaliaram-se os efeitos curativo e protetor e o tempo de absorção de fungicidas sistêmicos no controle da ferrugem do eucalipto. Azoxyztrobin, triadimenol, tetraconazole, tebuconazole e epoxiconazole + pyraclostrobin apresentaram 100% de ação curativa quando aplicados até quatro dias após a inoculação. Aplicados após sete dias, apenas azoxystrobin, tebuconazole e epoxiconazole + pyraclostrobin mantiveram o efeito curativo. Aos 10 dias depois da inoculação, os fungicidas reduziram a infecção, mas não controlaram totalmente a doença. Além do efeito curativo, azoxystrobin e triadimenol proporcionaram efeito protetor quando aplicados até 21 dias antes da inoculação de P. psidii. Avaliou-se o tempo mínimo de absorção de azoxystrobin, tebuconazole, triadimenol e trifloxystrobin. Esses quatro fungicidas foram absorvidos pela planta em todos os intervalos testados - 30, 60, 90 e 120 min - e inibiram a infecção de P. psidii em mudas de eucalipto.Item Development of microsatellite markers for the guava rust fungus, Puccinia psidii(Molecular Ecology Resources, 2008-03) Zhong, Shaobin; Yang, Baojun; Alfenas, Acelino CoutoWe developed and characterized 15 polymorphic microsatellite markers present in the genome of the guava rust fungus, Puccinia psidii. The primers for these microsatellite markers were designed by sequencing clones from a genomic DNA library enriched for a simple sequence repeat (SSR) motif of (AG). All these 15 primer pairs successfully amplified DNA fragments from a sample of 22 P. psidii isolates, revealing a total of 71 alleles. The observed heterozygosity at the 15 loci ranged from 0.05 to 1.00. The SSR markers developed would be useful for population genetics study of the rust fungus.