César Júnior Bueno

Reação de maracujazeiro-amarelo ao complexo fusariose-nematoide de galha

The present work was conducted in greenhouse conditions at APTA/Bauru, Sao Paulo State, during the first semester of 2007, with the objective of evaluating the resistance of two varieties of yellow passion fruit, Maguari and Afruvec, to the Fusarium solani-Meloidogyne incognita race 3 complex. The experimental delineation was entirely randomized in a 2 x 4 factorial arrangement, with 4-5 repetitions, with the plot constituted by 1 vase containing 1 plant. The appraised parameters in the assay were disease severity, caused by F. solani , measuring the lesion length (cm) in the collar zone of plants and number of galls formed by M. incognita race 3 in the root system. The two varieties of yellow passion fruit showed susceptibility to F. solani. Only in the Afruvec variety, the presence of nematode resulted in increase of fusariosis. As for resistance to the phytonematode, the Maguary variety was classified as resistant in the presence or absence of Fusarium. In contrast, for the Afruvec variety, the presence of Fusarium resulted in reduction of resistance to the nematode, going from moderately resistant to susceptible.

Mancha de mirotécio em algodoeiro causada por Myrothecium roridum

ABSTRACT Myrothecium leaf spot caused by Myrothecium roridum Tode ex Fr.was observed on cotton fields in Maranhao State, Brazil, causing yieldreduction of up to 60%. Disease symptoms are lesions with concentricnecrotic rings, with salient structures (sporodochia) irregularly distributed.Symptoms were observed on petioles, bracts, leaves and bolls of cottoncultivars Deltapine Acala 90, Fibermax 966 and Sure Grow 821. Thepathogen was isolated and cultivated on potato-dextrose-agar (PDA)medium. The pathogenicity was evaluated on detached healthy bollsfrom cotton cv. Fibermax 966 (R6 vegetative stage), previouslydisinfested. Thirteen isolates of M. roridum were tested, which included Meyer, M.C., Silva, J.C. da, Maia, G.L., Bueno, C.J., Souza, N.L. Myrothecium leaf spot of cotton caused by Myrothecium roridum . SummaPhytopathologica , v.32, n.4, p.390-393, 2006. RESUMO A mancha de mirotecio causada por Myrothecium roridum Tode exFr. foi observada em lavouras de algodao no sul do Maranhao, causandoreducoes de produtividade de ate 60%. Os sintomas da doenca sao lesoesnecroticas, circulares, com estruturas salientes, os esporodoquios, dedistribuicao irregular. Foram observadas lesoes nos peciolos, bracteas,folhas e macas de algodoeiro cv. Deltapine Acala 90, Fibermax 966 eSure Grow 821. O isolamento do fungo foi realizado em meio de culturabatata-dextrose-agar (BDA). O teste de patogenicidade foi realizado emmacas sadias, destacadas de algodoeiro cv. Fibermax 966, no estadiovegetativo R6, previamente desinfestadas. Foram testados 13 isoladosde

Preservação de fungos fitopatogênicos habitantes do solo

A preservacao de fungos fitopatogenicos por longos periodos de tempo e importante para que pesquisas possam ser realizadas a qualquer momento. Os fungos habitantes do solo sao organismos que podem produzir estruturas de resistencia em face de situacoes adversas, tais como ausencia de hospedeiros e ou condicoes climaticas desfavoraveis para a sua sobrevivencia. O objetivo deste trabalho foi desenvolver metodologias de preservacao de estruturas de resistencia para os fungos Fusarium oxysporum f.sp. lycopersici raca 2, Macrophomina phaseolina, Rhizoctonia solani AG4 HGI, Sclerotium rolfsii, Sclerotinia sclerotiorum e Verticillium dahliae. O delineamento foi inteiramente casualizado, com um metodo de producao de estruturas para cada fungo, submetido a tres tratamentos [temperatura ambiente de laboratorio (28±2oC), de geladeira (5oC) e de freezer (-20oC)] e com dois frascos por temperatura. Mensalmente, e por um periodo de um ano, a sobrevivencia e o vigor das colonias de cada patogeno foram avaliadas em meios de cultura especificos. Testes de patogenicidade foram realizados apos um ano de preservacao, com as estruturas que sobreviveram aos melhores tratamentos (temperatura) para todos os fungos. As melhores temperaturas (tratamentos) para preservar os fungos foram: a) F. oxysporum f.sp. lycopersici em temperatura de refrigeracao e de freezer (5,2 e 2,9 x 103ufc.g-1 de talco, respectivamente); b) M. phaseolina em temperatura de refrigeracao [100% de sobrevivencia (S) e indice 3 de vigor (V)] e S. rolfsii em temperatura ambiente (74,4% S e 1 V) e c) S. sclerotiorum e V. dahliae, ambos em temperatura de freezer (100% S e 3 V). Apos um ano de preservacao, somente V. dahliae perdeu a patogenicidade na metodologia desenvolvida.

Reaction of yellow passion fruit to fusariosis-root-knot nematode complex

The present work was conducted in greenhouse conditions at APTA/Bauru, Sao Paulo State, during the first semester of 2007, with the objective of evaluating the resistance of two varieties of yellow passion fruit, Maguari and Afruvec, to the Fusarium solani-Meloidogyne incognita race 3 complex. The experimental delineation was entirely randomized in a 2 x 4 factorial arrangement, with 4-5 repetitions, with the plot constituted by 1 vase containing 1 plant. The appraised parameters in the assay were disease severity, caused by F. solani , measuring the lesion length (cm) in the collar zone of plants and number of galls formed by M. incognita race 3 in the root system. The two varieties of yellow passion fruit showed susceptibility to F. solani. Only in the Afruvec variety, the presence of nematode resulted in increase of fusariosis. As for resistance to the phytonematode, the Maguary variety was classified as resistant in the presence or absence of Fusarium. In contrast, for the Afruvec variety, the presence of Fusarium resulted in reduction of resistance to the nematode, going from moderately resistant to susceptible.