Neofusicoccum batangarum causing dieback of mango in Florida

Authors: Puig, Alina; Winterstein, Michael - Mikey

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2021
Publication Date: 9/7/2021
Citation: Puig AS, Winterstein MC. 2021. Neofusicoccum batangarum Causing Dieback of Mango (Mangifera indica) in Florida. Agriculture, 11(9): 853. https://doi.org/10.3390/agriculture11090853
DOI: https://doi.org/10.3390/agriculture11090853

Interpretive Summary: Mango is produced commercially in Florida, and valuable germplasm collections of this crop are maintained in the southern part of the state. Dieback of mango trees has been reported in Florida since the 1970s, decreasing yield by up to 50%. It has been attributed to several fungi in the Botryosphaeriaceae family, but these identifications were based on morphology, which is no longer recommended for these genera. The absence of sequence information from early studies makes it difficult to interpret previous pathogen records. To determine the organism causing mango dieback in Florida, isolations were made from affected trees, and inoculation studies were carried out. The pathogen was identified as Neofusicoccum batangarum based on sequences from three genes (ITS, EF, BT), recommended for members of the Botryosphaeriaceae family. Commercial mango production encompasses approximately 1,350 acres in the state of Florida, and information on this pathogen is relevant to growers in the area. This is the first study of mango dieback in Florida using sequence-based identification.

Technical Abstract: Mango (Mangifera indica) is an economically significant crop, and is affected by dieback in nearly all commercial production areas. Due to the wide range of organisms previously associated with these disease symptoms in Florida, isolations and pathogenicity tests were carried out to determine the causal organism. The pathogen was identified as Neofusicoccum batangarum based on genetic sequences from three loci (ITS, EF, BT), recommended for members of the Botryosphaeriaceae family. Possible infection routes were determined by inoculating wounded and unwounded stems with N. batangarum. Trees wounded prior to pathogen inoculation developed larger lesions (5.85cm ±1.51) than unwounded trees (0.51cm ±0.48), p<.0003. In addition, lesions only developed at a small number of inoculation sites in the absence of wounds (14.3%), compared to 93% when stems were wounded. No necrosis was observed in the negative controls. This study provides molecular data on N. batangarum, and evidence of its role causing mango dieback in Florida.