Effect of plant extracts on morphological and pathological potential of seed-borne fungi on cucumber seeds

Seed-borne fungi of cucumber are serious problem worldwide causing damping-off, root rot and wilt diseases on cucumber plants. Several pathogenic fungal isolates were isolated from cucumber seed samples collected from commercial markets in Egypt. Fusarium oxysporum and Fusarium solani were the common fungi isolated from cucumber seeds followed by Alternaria sp, Rhizoctonia solani, Helminthosporium sp. and Penicillium spp. Pathogenicity test indicated that F. oxysporum was the best fungal significantly induced damping off on cucumber plants. Water extract of peppermint extract was the most effective completely inhibited spore germination and mycelial growth of F. oxysporum at concentration of 2%, followed by rheum and garlic extracts which completely inhibited fungal conidiospore germination and mycelial growth on agar medium by the rate of 3%. Cucumber seeds treated with 2% peppermint extract caused a highly reduction of damping off of cucumber and reduced fungal transmission from seeds to seedlings. Furthermore, vigor of cucumber seedlings raised from the treated seeds was better than that developed from the untreated ones.