Effect of Some Bioagents on Cladosporium cucumerinum Causing Cladosporium Leaf Spot: A New Challenge in Watermelon Production in Egypt.

Seven isolates of bioagents, Trichoderma harzianum, Pseudomonas fluorescens, Bacillus subtilis, Anabena oryzae, Nostoc muscorum, Chaetomium globosum and Gliocladium catenulatum were used to control cladosporium leaf spot. Nostoc muscorum mixed with Pseudomonas fluorescens successfully reduced the growth and spore germination of Cladosporium cucumerinum. The potentially of the bioagents significantly reduced the cladosporium leaf spot disease incidence and inhibiting its progress when used each alone or as mixtures under field conditions. The bioagents generally improved the watermelon plants and significantly increased the plant height, number of branches, fruit numbers and fruits weight due to treatment with the tested bioagents either each alone or in mixture compared to the untreated control.