Coffee fruit rot (CFR) is a well-known disease worldwide mainly caused by Colletotrichum spp., the most important species being C. kahawae subsp. kahawae. In Puerto Rico, Colletotrichum spp. were identified as pathogens of coffee fruits. The coffee berry borer (CBB) was shown to be a dispersal agent of these fungi and the role of Fusarium affecting coffee fruits was suggested. In this study we demonstrated that Fusarium spp. also cause CFR in Puerto Rico. Fusarium spp. are part of the CBB mycobiota, and this insect is responsible for spreading the pathogens in coffee fields. We identified nine Fusarium spp. (F. nirenbergiae, F. bostrycoides, F. crassum, F. hengyangense, F. solani-melongenae, F. pseudocircinatum, F. meridionale, F. concolor and F. lateritium) belonging to six Fusarium species complexes isolated from CBBs and from rotten coffee fruits. Pathogenicity tests showed that F. bostrycoides, F. lateritium, F. nirenbergiae, F. solani-melongenae and F. pseudocircinatum were pathogens causing CFR on green coffee fruits. Fusarium bostrycoides was the predominant species isolated from the CBB mycobiota and coffee fruits with symptoms of CFR, suggesting a close relationship between F. bostrycoides and the CBB. To our knowledge, this is the first report of F. bostrycoides, F. solani-melongenae, F. pseudocircinatum and F. nirenbergiae causing CFR worldwide and the first report of F. lateritium causing CFR in Puerto Rico. Understanding the CFR disease complex and how the CBB is contributing to disperse different Fusarium spp. in coffee farms is important to implement disease management practices in Puerto Rico and in other coffee-producing countries.
Keywords: Fungal Pathogens; Genetics; Host Parasite Interactions; Pathogen Detection; Population Biology.