Integrating biological control as a sustainable approach for managing silver scurf and black dot in potatoes

Summary

The potato (Solanum tuberosum) is a globally cultivated crop, but blemish diseases such as silver scurf (Helminthosporium solani) and black dot (Colletotrichum coccodes) cause significant quality and market losses, black dot could reduce yield up to 30–50 % with estimated market loss of ∼ £3 million yearly and silver scurf can cause tuber weight losses up to ∼ 17 %. The origins of these diseases are multifaceted, involving complex interactions among pathogens, environmental conditions, and the host plant. This review aims to offer a thorough examination of current knowledge on their biology, epidemiology, and management practices, highlighting that cultural practices such as crop rotation, reduced tillage, regulated irrigation, curing and controlled storage conditions reduce disease severity, but are insufficient as standalone management strategies. Numerous bacterial and fungal biocontrol agents have shown strong in vitro inhibition but still require field validation. Plant derived metabolites and microbial metabolites also exhibited potent antifungal activity against these diseases under in vitro dual culture assays, mini-tuber assays and as post-harvest protectants. Although combining biocontrol agents with early detection, optimized agricultural practices, and regulated storage conditions has not yet been fully validated for potato tuber blemish diseases, similar integrated pest management strategies have proven successful against other crop diseases, highlighting the potential of this approach but also signifying the need for further research. Thus, this review highlights the existing biological management approaches investigated against black dot and silver scurf and the possibility of incorporating it with other non-chemical approaches for sustainable management of these diseases.