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RESEARCH PRODUCT

Biocontrol activities of Pseudomonas fluorescens against asparagus pathogen

subject

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Pseudomonas spp. and their metabolites present environmentally friendly alternative to chemical products to improve plant growth in many different applications. Extensive studies have shown that these microorganisms and their metabolites could have an important role in agriculture and horticulture in improving crop productivity. The aim of the research was to assess a potential biological activity of Pseudomonas fluorescens against Fusarium oxysporum isolated from the spears of asparagus. The antagonistic properties of metabolites were assayed with a dual culture plate method on PDA and Czapek media for supernatants obtained from 6, 12, 24 and 48-hour culture of P. fluorescens. The culturing process was conducted at 26ºC for 8 days and the fungal linear growth was measured every 1-2 days and compared to control. The fungistatic activity of P. fluorescens was estimate on the basis the growth rate index. The highest inhibition of the linear growth of mycelium, reaching 61%, has been found for 48-hour supernatants at OD = 2.0 and lowest for 12-hour supernatants on Czapek medium compared with the control trial. Significantly weaker linear growth of mycelium within the range of 4.0-33.0% was observed on PDA medium with a maximum inhibition for 48-hour supernatants at OD = 2.0 (33.0%). Promising method to asparagus protection against Fusarium sp. may be the use of P. fluorescens as the biocontrol agents.