Effect of antagonistic bacteria and its formulation to control fusarium wilt disease on shallot

Abstract

Biocontrol of pathogenic fungi using antagonistic bacteria isolated from the soil (rhizosphere) is expected to suppress plant diseases to obtain good quality of yield, and thus support sustainable agriculture. The study aimed to formulate and scale up the production of rhizosphere-based bacterial biopesticides that effective in suppressing the onset of Fusarium wilt disease caused by Fusarium oxysporum f.sp. cepae on shallot. The experiment to evaluate the effectiveness of biocontrol agents against Fusarium wilt disease was carried out employing shallot cv. ‘bima curut’ in the field (Patrol-Indramayu,West Java), from May to August 2018 growing season. The experimental plot of 1.20 m x 18 m, was prepared using plant spacing of 15 × 10 cm. The solid formulation of kaolin-based bacteria (containing bacterial cells of 109 CFU/mL) was applied with variation of four concentrations range from 0.3125 to 2.5 mL/L. The experiment was arranged in randomized block design with four replications. Shallot beginning at 30 days old-plant was sprayed three times at one-week intervals. The results showed that the disease intensity was significantly lower than in control. Under natural infection, the spraying application of a bacterial isolate (DSB2) using kaolin formulation (107 CFU/mL) with a formula concentration of 1.25 mL/L could reduce the disease intensity. Tuber yield of formula treatments was significantly higher than that of control. Thus, the use of bacterial formula as environmental-friendly biocontrol agent in this study might be further recommended in controlling Fusarium wilt disease on shallots.