Yield, Quality and Disease Responses of Three Watermelon Varieties as Subjected to Indigenous Microorganisms

This study evaluated the effectiveness of indigenous microorganism (IMO) in association with wheat bran and enhanced with NPK fertilizer, to suppress Fusarium wilt and Gummy stem blight and improve watermelon production. A split-plot experimental design with three watermelon varieties (V1: Kolosse; V2: Pinksweet; V3: Kaolack) and six treatments were used. Three cultivation periods were conducted with different treatment combinations. Experiment 1 and 2 which consisted of control, 30 g IMO, 38 g IMO , 46 g IMO, NPK + Fungicide, 38 g IMO + NPK. Experiment 3 were, based on previous results, IMO rate was increased; the six treatments included control, 50 g IMO, 150 g IMO, 250 g IMO, NPK + fungicide and 150 g IMO + NPK. Epidemiological parameters and morphological identification of two pathogens as well as agronomic parameters were assessed. The results revealed that in the first experiment, 46 g IMO reduced the disease incidence of Fusarium wilt by 23.29 % compare to the control; in the second campaign, no Fusarium wilt symptoms were observed in plants treated with 38 g IMO , 46 g IMO and the combination 38 g IMO +NPK. On the contrary, 30 g IMO increased the disease severity of Gummy stem blight by 44.41 % to 90.42 % compared to NPK + F followed by control. Morphological identification confirmed Fusarium oxysporum sp. and Stagonosporopsis sp. as the causal pathogens. Treatment 150 g IMO + NPK increased the weight of watermelon fruit by 89.30 % compared to control, followed by 250 g IMO. Kolosse variety exhibited the highest TSS in treatment combination with up to 10.40 ° Brix in experiment 3 followed by Pinksweet 10.23 ° Brix. This finding demonstrates that IMO bokashi represented a viable strategy for improving watermelon health and productivity.