Caracterización cultural, patogénica y sensibilidad in vitro de phytophthora spp. asociado a enfermedades de mazorca de cacao (theobroma cacao l)

The objective of this work was to Isolate and Identify the fungi that cause the disease known as black pod in cocoa, in the provinces of Manabi and Esmeraldas, as well as determine the sensitivity in vitro; cultural characterization; Pathogenicity and Aggression of these isolates. This work was developed in the Molecular Biology Laboratory of the Polytechnic Agricultural School of Manabi, Calceta-Ecuador. The fruits that showed symptoms of black cob were collected in cocoa crops in Flavio Alfaro and Quininde canton. For the identification of the fungus, semi-permanent sheets were prepared and observations were made under a microscope which showed a wide diversity in the types of sporangia and clamidospores. The pathogenicity of the isolates of Phytophthora spp. and it was confirmed two and three days after inoculation. The isolates of Phytophthora spp. from the province of Esmeraldas, they presented more aggressiveness than those isolated from the province of Manabi. The growth patterns of the colonies were described, where the strains showed a uniform growth pattern in each of the four-culture media, arachnoid in the PDA and EMA media and crashed in V8 and CA. The strains showed greater growth in the CA and V8 culture media. In the in vitro sensitivity test, fungicides (Carboxin-Thiram, Mancozeb-Cymoxanil, Mancozeb-Metalaxyl and Metalaxyl) exercised control in the strains of Phytophthora spp.