Morfologia, patogenicidade e sensibilidade a fungicidas em isolados de thielaviopsis associados à resinose do coqueiro no Ceará

Abstract

Coconut palm (Cocos nucifera) is one of the most important cultivated plants in the world, and its production is affected by several factors, especially diseases. Coconut tree stem bleeding is one of the main diseases that affect this crop and its etiological agent is the morphospecies Thielaviopsis paradoxa. Thus, the objective of this study was to characterize T. paradoxa isolates associated with coconut stem bleeding in the municipalities of Beberibe, Fortaleza, Paraipaba and Pentecoste, as well as to characterize its causal agent in production areas of Ceará State. Morphology, pathogenicity and sensitivity to fungicides were used in the characterization of the pathogen. Five isolates of the fungus T. paradoxa were obtained in samples showing symptoms of the disease. The fungus showed variation in colony color, mycelial growth and micromorphology. The fungicides cyproconazole and difenoconazole were efficient to control fungal growth at doses of 50, 100 and 200 µg/mL. The pathogenicity test confirmed the ability of the fungal isolates to colonize the plant tissue of the fruit. The isolates showed variation in colony color, mycelial growth and micromorphology. The pathogenicity test confirmed the etiology of the disease and showed variation in the aggressiveness of the isolates.