Suppression of Colletotrichum spp. on grape berries, vine leaves, and plants using Bacillus velezensis S26 endospores

Abstract

Grape ripe rot and anthracnose are fungal diseases caused by Colletotrichum spp., which negatively impact viticulture. Disease management often involves the use of synthetic fungicides, whose toxicity poses risks to the environment and human health. As a result, biopesticides have been developed as an alternative approach for suppressing plant diseases in the field or postharvest. The present study aimed to evaluate the inhibitory potential of a bacterial inoculant containing endospores of Bacillus velezensis strain S26 against seven isolates of Colletotrichum spp. in grapevines (Vitis vinifera and V. labrusca). The bioassays were performed on grape berries, leaf discs, and micropropagated plants using both a fresh inoculant and an inoculant stored for six months at room temperature. The findings revealed that the biocontrol activity was more pronounced in fruit when compared to vine plants and leaves. Besides, the bacterial inoculant demonstrated a strain-dependent capacity to suppress the pathogen, with higher effectiveness observed in controlling the disease in V. vinifera compared to V. labrusca. Regarding the effect of storage on bacterial antagonism, the stored inoculant maintained its inhibitory ability against the pathogen. In summary, B. velezensis S26 demonstrates potential as a biocontrol agent against Colletotrichum spp. in grapevines, making it suitable for use in the development of bioproducts.