ARS | Publication request: Effect of Botanical Extracts on the Population Density of Fusarium Oxysporum in Soil and Control of Fusarium in the Greenhouse

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 22, 1999
Publication Date: N/A

Interpretive Summary: Several commercial formulations of plant extracts and essential oils were investigated as possible alternatives to soil fumigation with methyl bromide for control of Fusarium wilt diseases. Soil was infested with Fusarium oxysporum f.sp. chrysanthemi (F.o.c.) and treated with 1, 5, and 10% aqueous emulsions of formulated extracts of clove (70% clove oil), neem (90% neem oil), pepper/mustard (chili pepper extract and essential oil of mustard), cassia (extract of cassia tree), and Banrot (a standard fungicide) in separate experiments. Population densities of F.o.c. in soil were determined over time. Treatment of the soil with 5 and 10% aqueous emulsions resulted in significant (P<0.05) differences among treatment mean values at each assay date. The pepper/mustard, cassia, and clove extracts added as 10% aqueous emulsions reduced the population density of F.o.c. in soil 99.9, 96.1, and 97.5%, respectively, after 3 days compared to the untreated control. In greenhouse experiments, soil infested with Fusarium oxysporum f.sp. melonis was treated with 1, 5, and 10% aqueous emulsions of formulated extracts, incubated in closed plastic bags for 1 week, and planted with muskmelon seed (cv. Gold Star). Treatment of infested soil with 5 and 10% aqueous emulsions of the botanical extracts resulted in differences among treatments after 5-6 weeks. The pepper/mustard, cassia, and clove extracts suppressed disease development in repeated experiments (80-100% healthy plant stand) compared to the untreated infested soil (<20% stand). The observed reduction in the pathogen population and the increase in healthy plant stand in the greenhouse suggests that these extracts could have important roles in biologically-based management programs for control of Fusarium wilt

Technical Abstract: Soil infested with Fusarium oxysporum f.sp. chrysanthemi (F.o.c.) was treat with 1, 5, and 10% aqueous emulsions of formulated extracts of clove (70% clove oil), neem (90% neem oil), pepper/mustard (chili pepper and essential oil of mustard), cassia (extract of cassia tree), and Banrot (a standard fungicide) in separate experiments. Population densities of F.o.c. were determined over time. Treatment of the soil resulted in significant (P<0. differences among treatment mean values at each assay date. Pepper/mustard, cassia, and clove extracts added as 10% aqueous emulsions reduced the population density of F.o.c. 99.9, 96.1, and 97.5%, respectively, after 3 d compared to the untreated control. Soil infested with Fusarium oxysporum f.sp. melonis also was treated with 1, 5, and 10% aqueous emulsions of formulated extracts, incubated in closed plastic bags for 1 week, and plant with muskmelon (cv. Gold Star) in the greenhouse. Treatment of infested so oresulted in differences among treatments after 5-6 weeks. The pepper/must cassia, and clove extracts suppressed disease development in repeated experiments (80-100% healthy plant stand) compared to the untreated infeste soil (<20% stand). The observed reduction in the pathogen population and increased healthy plant stand in the greenhouse suggests that these extract could have important roles in biologically-based management programs for control of Fusarium wilt diseases.