In vitro antifungal activities of selected spice extract against Fusarium species and pathogenicity of the Fusarium isolates

The effect of aqueous and ethanolic extract of five spices (ginger, turmeric, black pepper, cinnamon and clove) were investigated against economically important pathogenic fungi (Fusarium sp). The in vitro investigation revealed that the ethanolic extracts of Syzygium aromaticum inhibited mycelial growth of Fusarium species. The extracts of Zingeber officinale (ginger), Cucumer longer (turmeric), Piper nigrum (black pepper), Cinamomum verum (cinnamon) and aqueous extract of Syzygium aromaticum (clove) inhibited fungal development ranging from varying concentrations. The Fusarium specie were evaluated to study their pathogenicity on four healthy potato varieties (caruso, connect, Jelly and Marabel) tubers. The tuber rot symptoms were observed 3 weeks (21 days) after inoculation on healthy potato tubers with the Fusarium species isolated from potato cultivated soil. Lesion size was varied in the tubers inoculated. The experiment was therefore to assess the depth and width of lesion among isolates. Result revealed that Fusarium was strongly pathogenic to inoculated tubers though B/Ladi isolate were less pathogenic on tubers in vitro. The isolates inoculated were re-isolated from infected tubers to proof Koch’s postulate. The present study revealed that Fusarium species are associated with tuber rot of potato in Plateau State.