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Phytopathogen fungi related to vascular wilt and die back in Tectona grandis Lf (teak) field in Ecuadorian Tropical Rainforest.

Abstract:

Teak plantations (Tectona grandis L. f.) in Ecuador are being affected by a complex disease of vascular wilt and dieback, with epidemic characteristics, without knowing the causal agent (s) so far. We proposed to describe the symptomatology of the disease and identify phytopathogenic fungi associated with diseased trees in the Ecuadorian Humid Tropic by morphophysiology. Three plantations of 2, 5 and 7 years of age were selected, in each three plots of 500 m 2 were delimited. The symptomatologic description was made, evaluated the incidence and severity of the disease using a scale of five categories. By plot, three trees were dissected, whose tissues were taken to the laboratory, where three methodological strategies were used (wet chamber, carrot sandwiches, and potatodextrose-agar culture medium, PDA) to stimulate the expression of phytopathogens. In diseased trees, chlorosis, turgor loss, dry growth apices, emission of epicormic shoots in the stem, and fulminating wilt were detected. It was isolated and identified Ceratocystis fimbriata Ellis & Halst., and Fusarium species. consecutively with the three methodological strategies employed. The incidence of the disease was 16.6%, 15.2%, and 11.6% for plantations of 2, 5 and 7 years, respectively. The sick trees in the plantation of 2 years were found in scales 2, 4 and 5, while in plantations of 5 and 7 years they were located in scales 2, 3 and 5 of progress of the disease.