Morfologia, patogenicidade e sensibilidade a fungicidas de isolados de Lasiodiplodia associados à podridão peduncular do coqueiro no Ceará

Abstract

Coconut (Cocos nucifera L.), originating in Southeast Asia, is present all over the world, covering more than 200 countries on millions of hectares. In this way, it is socially and economically important for the generation of income through the manufacture of products in the agro-industries, handicrafts and mainly in the consumption of in natura coconut water. With the expansion of the culture in Brazil, the occurrence of phytosanitary problems also intensified, including stem rot. It is the main post-harvest disease and responsible for important production losses and problems in the commercialization of the fruits. This disease is characterized by its difficult control. The causal agents of coconut stem rot are fungal species of the genus Lasiodiplodia. Thus, the objective of this study was to investigate the occurrence of stem rot on coconut fruits, as well as to characterize its causal agent in production areas in Ceará State. Thus, morphological and pathogenic characterization and sensitivity to fungicides were used. Five isolates of the fungus Lasiodiplodia 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 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.