Abstract

ZUNINI ORTEGA, Rubén Darío  and  ORREGO FUENTE, Aida Lorenza. Fungi incidence in Toona ciliata seeds and evaluation of pathogenicity of Fusarium sp. and Phomopsis sp. Investig. Agrar. [online]. 2013, vol.15, n.2, pp.107-112. ISSN 2305-0683.

Toona canker is a disease characterized by thickening in stems and branches, causing vertical cracks in the cortex and disabling the wood for industry. The objective of this work was to evaluate the incidence of fungi in seeds of Toona ciliata and verify the pathogenicity of Fusarium sp. and Phomopsis sp. as causers of canker. Experiments were performed in the laboratory and greenhouse of the Departamento de Protección Vegetal of the Facultad de Ciencias Agrarias, Universidad Nacional de Asunción. The blotter method and PDA culture medium (potato, dextrose agar) were employed to evaluate the health of the seeds, using in each case 400 seeds. In the greenhouse, a completely randomized design with 3 treatments and 5 replicates was used; the experimental unit consisted of 20 pots with one seedling each. Treatments consisted of inoculation of seedlings with application of a disk of 5 mm of fungi Fusarium sp. and Phomopsis sp. in the stems, and the control treatment following Koch's Postulates. Plants were evaluated at 35 and 70 days post inoculation. Data were analysed for variance and the means compared by Tukey test. Identified fungi were Fusarium sp., Phomopsis sp., Aspergillus sp., Alternaria sp., Colletotrichum sp., Penicillium sp., Curvularia sp. and Helminthosporium sp. It is concluded that Fusarium sp. and Phomopsis sp. are pathogenic, causing the disease known as Toona canker

Keywords : Toona ciliata; Fusarium sp; Phomopsis sp; canker; incidence.

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