Identification of Fungi in the Botryosphaeriaceae Family Associated with Stem Blight of Vaccinium spp. in the Southeastern United States

Stem blight is a major disease of blueberry caused by Botryosphaeriaceae fungi. Chemical and cultural management options are limited, putting emphasis on breeding efforts to identify sources of resistance. The efficacy and durability of host resistance could be impacted by the species composition of the pathogen population in a region and by the isolates employed in the screenings used to identify the resistance. Samples (365) were collected from southern highbush (SHB) and rabbiteye blueberry (REB) cultivars from 28 sites in the southeastern US (AL, FL, GA, NC, and SC). Colony morphology identified 86% of the isolates as Botryosphaeriaceae. Conidia morphology and Maximum Likelihood analysis of the Internal Transcribed Spacer rDNA regions (ITS), translation elongation factor one alpha (tef1-a), and btubulin were used to identify isolates at genera or species level. A PCR-restriction fragment length polymorphism (PCR-RFLP) test was used to identify isolates to genus. Neofusicoccum and Lasiodiplodia were the predominant genera. N. kwambonambiense, N. ribis, L. theobromae and L. pseudotheobromae were the most common species isolated. Phylogenies conducted with a limited number of isolates indicated non-clonal and potentially diverse populations occur on blueberry that warrant additional study. Botryosphaeria corticis, B. dothidea, and Diplodia seriata were isolated infrequently. (c) 2022 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the species composition and resistance identification of stem blight fungi in blueberry cultivation areas in the southeastern US. It was found that Botryosphaeriaceae was the major pathogen population, and Neofusicoccum and Lasiodiplodia were the predominant genera. N. kwambonambiense, N. ribis, L. theobromae, and L. pseudotheobromae were the most common species isolated.