Effectiveness of the Combination Trichoderma spp. and Neem Leaf Powder (Azadirachta indica L.) Against Fusarium Oxysporum f. sp. melonis in Vitro

Abstract

Fusarium wilt disease caused by Fusarium oxysporum f. sp. melonis is a major factor reduces of melon (Cucumis melo L.) production in Indonesia. Control using chemical fungicides has not been effective and poses risks to the environment and health. The aim of this experiment was to find out more accurate treatment combination of Trichoderma spp. as biological control agents with neem leaf powder (Azadirachta indica) as a botanical fungicide for inhibiting the growth of F. oxysporum in vitro. The Trichoderma species used in this study were collected by the Plant Pathology Laboratory collection of Udayana University. The research was conducted using a Randomized Complete Design (RCD) with two factorial treatments comprising three Trichoderma species (T. harzianum, T. koningii, and T. viride) and four neem leaf powder concentrations (0 g L⁻¹, 15 g L⁻¹, 30 g L⁻¹, and 45 g L⁻¹) and 3 replications. Antagonistic activity was assessed using the dual culture method on potato dextrose agar (PDA) medium, with observations conducted over seven days observed parameters included pathogen colony growth and percentage of inhibition. The results showed that the combination of Trichoderma spp. and neem leaf powder significantly inhibited the growth of F. oxysporum in vitro, with varying effectiveness among Trichoderma species. The best inhibition was obtained from the combination of Trichoderma koningii and neem leaf powder at a concentration of 45 g L⁻¹, which completely inhibited the growth of F. oxysporum (100%) by day 5 without suppressing the growth of Trichoderma.