Biocontrol of Fusarium wilt disease in cucumber with improvement of growth and mineral uptake using some antagonistic formulations.

Fusarium wilt disease in Cucumber (Cucumis sativus L.) is widespread, responsible for serious economic losses. Amongst totally 15 isolates of Fusarium spp., obtained from different localities of Sohag governorate, Egypt, only the identified isolates as F. oxysporum were pathogenic on cucumber Denmark Beta-Alpha cv. and caused wilt symptoms. Totally 22 isolates of Trichoderma spp., B. subtilis and Pseudomonas spp., were obtained from rhizosphere of cucumber and some available commercial formulations and then tested for antagonistic activity against F. oxysporum (FO5) in vitro. The highest inhibitory effect on growth of FO5 was observed by isolate Trichodex of T. harzianum (89.29%) followed by Th4 of T. harzianum, Serenade and MBI 600 of B. subtilis, PS3 of Pseudomonas spp., and Treico and Tv2 of T. viride. Pot experiments were performed to investigate the effects of formulated antagonists as seed treatment on Fusarium wilt incidence, growth and mineral uptake of cucumber. Results showed that all tested formulations significantly reduced percent of wilted plants and disease severity, and improved plant growth by increasing length of shoot and root, fresh and dry weight of shoot and root system, and number of leaves and flowers per plant compared with untreated control. They also significantly increased nutrient contents of plant shoot including N, P, K, Ca, Fe, Mn, Cu, and Zn. Magnesium content in shoot slightly not significantly increased. Formulation of Trichodex was the most effective ones followed by Serenade, Th4 and PS3.