Control of fusarium wilt disease of cucumber using rhizospheric antagonistic fungi

Fusarium wilt disease caused by fusarium oxysporum f. sp. cucumerinum is a severe disease of cucumbers causing yield losses worldwide. various experiments were conducted to assess the antifungal potential of fungal bio-agents isolated from soil and cucumber seed (bio-priming). trichoderma koningii seemed to be the most effective bio-agent against f. oxysporum f. sp. cucumerinum with mycelial inhibition rate above 90%, followed by aspergillus niger (87.70%) under laboratory conditions. results showed that t. koningii was found effective to enhance the germination rate (95.07%). in greenhouse experiments, t. koningii applied preventively on cucumber inoculated with f. oxysporum f. sp. cucumerinum generated the lowest disease severity index (0.42), mortality (13.33%) and wilting rate (23.33%) and the highest fresh (0.857 g) and dry (0.180 g) weight of root, and root volume (2.04 cm3). based on these results, t. koningii applied preventively against f. oxysporum f. sp. cucumerinum on cucumber plants could be recommended as a biocontrol agent. however, although a. niger was effective against the tested phytopathogen, it is not recommended for biological control due to its carcinogenic properties.