Botryosphaeriaceae Associated With Racemes, Fruits and Leaves of Macadamia in South Africa

• DOI: 10.1111/ppa.14107
• Publication Date: 2025-04-14T16:06:31Z
• Authors: Ntaoleng A. Maduke; Bernard Slippers; Elna van der Linde; Mike J. Wingfield; Gerda Fourie

ABSTRACTSpecies in the Botryosphaeriaceae are common in the endophytic microbiome of woody plants. Some of these are well known to cause branch die‐back and decline of macadamia trees and have also been associated with diseases of their fruits and leaves. The aim of this study was to characterise species of Botryosphaeriaceae from asymptomatic and symptomatic tissues of macadamia fruits, leaves and racemes in South Africa. Symptomatic tissues included die‐back of the racemes, husk rot on fruits and brown leaf blight. Eleven species were identified based on analysis of DNA sequence data for the rDNA internal transcribed spacer (ITS), tub2, tef‐1α and rpb2 gene regions. These included Diplodia pseudoseriata, D. allocellula, Lasiodiplodia sp., L. euphorbicola, L. gonubiensis, L. pseudotheobromae, L. theobromae, Neofusicoccum australe, N. kwambonambiense, N. luteum and N. parvum. The results revealed a greater species diversity and isolation frequency from leaves compared to fruits and racemes, which highlights the important role that the species play in brown leaf blight. All isolates used in pathogenicity trials produced lesions on both fruits and leaves, but Neofusicoccum and Lasiodiplodia species were more aggressive. Considering the frequency of association with diseased tissues and the pathogenicity trials, L. pseudotheobromae, L. theobromae, N. parvum and N. kwambonambiense are the most important species to focus on for future disease resistance screening of planting material. This study provided new insights into the association of Botryosphaeriaceae species with important canopy diseases such as brown leaf blight and husk rot in South Africa and will contribute to their future management.