Coffee fruit rot: the previously unrecognized role of fusarium and its interactions with the coffee berry borer (Hypothenemus hampei)

Authors: SERRATO DIAZ, LUZ; MARIÑO-CARDENAS, YOBANA - UNIVERSITY OF PUERTO RICO; GONZALEZ DE JESUS, JOSELYN - UNIVERSITY OF PUERTO RICO; Goenaga, Ricardo; BAYMAN, PAUL - UNIVERSITY OF PUERTO RICO

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2023
Publication Date: 2/22/2024
Citation: Serrato Diaz, L.M., Mariño-Cardenas, Y.A., Gonzalez De Jesus, J., Goenaga, R.J., Bayman, P. 2024. Coffee fruit rot: the previously unrecognized role of fusarium and its interactions with the coffee berry borer (Hypothenemus hampei). Phytopathology. https://doi.org/10.1094/PHYTO-02-24-0046-R.
DOI: https://doi.org/10.1094/PHYTO-02-24-0046-R

Interpretive Summary: Coffee fruit rot (CFR) is an important disease that affects coffee production and quality. Several Colletotrichum species have been reported causing CFR worldwide. In Puerto Rico, four species of this pathogen were detrimental to coffee fruits. However, the role of Fusarium species affecting coffee was also suggested but pathogenicity tests were not conducted. This study demonstrated the following: 1) Fusarium spp. cause CFR in Puerto Rico; 2) the Coffee berry borer (CBB) has Fusarium spp. as part of its microbiota; 3) this insect is responsible of spreading Fusarium spp. In coffee fields. A total of nine Fusarium species in six Fusarium species complexes were identified and collected from CBBs and from rotten coffee fruits in the field. Pathogenicity tests showed that five Fusarium species (F. bostrycoides, F. lateritium, F. nirenbergiae, F. solani-melongenae and F. pseudocircinatum) were pathogens of coffee causing CFR on green coffee 15 days after inoculation. Internal rot was significantly higher than external rot indicating that these pathogens use the hole left by the CBB to penetrate and infect coffee tissue. Fusarium bostrycoides was the most predominant species isolated from the CBB microbiota, coffee fruits with symptoms of CFR and from isolates recovered from pathogenicity tests suggesting a possible symbiosis between F. bostrycoides and the CBB. To our knowledge, this is the first report of F. botryscoides, F. solani melongenae, F. pseudocircinatum and F. nirenbergiae causing CFR worldwide and the first report of F. lateritium causing CFR in Puerto Rico. Fusarium species can produce mycotoxins and may cause diseases in plants. Understanding that CFR is a disease complex that includes Fusarium species and how the CBB is contributing to disperse these fungi in coffee farms is important to address the best management practices of this disease in Puerto Rico and other coffee-producing countries worldwide.

Technical Abstract: Coffee fruit rot (CFR) is a well-known disease worldwide. It is mainly caused by Colletotrichum spp. being the most important species C. kahawae subsp. kahawae which causes coffee berry disease in Africa. In Puerto Rico, four Colletotrichum spp. (C. fructicola, C. siamense, C. theobromicola and C. tropicale) were identified as pathogens of coffee fruits; the coffee berry borer (CBB) was the dispersal agent of these fungi and the role of Fusarium spp. affecting coffee fruits was suggested. However, in this study we demonstrate that Fusarium spp. also cause CFR in Puerto Rico, the CBB has Fusarium spp. as part of its microbiota and this insect is responsible of spreading Fusarium spp. in coffee fields. We identified nine Fusarium spp. in six Fusarium species complexes from CBBs and from rotten coffee fruits collected in the field. One (F. nirenbergiae) belongs to the F. oxysporum species complex, four (F. bostrycoides, F. crassum, F. hengyangense, and F. solani-melongenae) belong to the Fusarium solani species complex, one (F. pseudocircinatum) to the Fusarium fujikuroi species complex, one (F. meridionale) in the Fusarium sambucinum species complex, one (F. concolor) in the Fusarium concolor species complex and one (F. latericium) to the Fusarium lateritium species complex. Five Fusarium spp. (F. bostrycoides, F. concolor, F. lateritium, F. meridionale and F. pseudocircinatum) were isolated from adult female CBBs while six Fusarium spp. (F. bostrycoides, F. crassum, F. hengyangense, F. lateritium, F. nirenbergiae and F. solani-melongenae) were isolated from rotten coffee fruit tissue. Pathogenicity tests showed that five Fusarium spp. (F. bostrycoides, F. lateritium, F. nirenbergiae, F. solani-melongenae and F. pseudocircinatum) were pathogens of coffee causing CFR on green coffee 15 days after inoculation. Internal rot was significantly higher than external rot indicating that these pathogens use the hole left by the CBB to penetrate and infect coffee tissue. Fusarium bostrycoides was the most predominant species isolated from the CBB microbiota, coffee fruits with symptoms of CFR and from isolates recovered from pathogenicity test suggesting a possible symbiosis between F. bostrycoides and the CBB. To our knowledge, this is the first report of F. botryscoides, 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, the interaction with the CBB and how the CBB is contributing to disperse different species of Fusarium in coffee farms is important to address the best management practices of this disease in Puerto Rico and other coffee-producing countries worldwide.