Characterisation of Fusarium and Neocosmospora Species Associated With Crown Rot and Wilt of African Eggplant (Solanum aethiopicum) in Ghana

Abstract

African eggplant (AEP) (Solanum aethiopicum group Gilo) is an important vegetable with considerable economic value in Ghana and tropical Africa. However, fungal diseases threaten its cultivation. Surveys conducted in 2021 and 2022 growing seasons across 35 commercial farms in five regions of Ghana revealed symptoms of crown rot and wilt affecting AEP. This study was undertaken to identify and characterise 36 fungal isolates causing these diseases in AEPs using morphological, molecular and pathogenicity assays. Morphological and molecular analyses of the Btub2, Tef-1α and Rpb2 sequences identified two Fusarium species (F. elaeidis and F. fredkrugeri) and three Neocosmospora species (N. falciforme, N. suttoniana and N. solani) associated with the plant diseases. F. elaeidis (14 isolates) and N. falciforme (14) were the most commonly isolated species from symptomatic plants. Specifically, F. elaeidis was found in wilting plants, while F. fredkrugeri and the three Neocosmospora spp. were more associated with wilting plants with crown rot symptoms than plants with only wilt symptoms. All identified species exhibited pathogenicity when inoculated onto AEP roots and stems, confirming field observations. F. elaeidis was the most aggressive in inducing wilt symptoms, while N. solani and N. suttoniana were particularly aggressive in inducing crown rot symptoms. This study is the first to document that F. elaeidis, F. fredkrugeri, N. falciforme and N. suttoniana are pathogens causing wilt and crown rot in AEP in Ghana. These findings provide essential insights for developing effective disease management strategies to reduce losses from these fungal species.