Efficacy of microorganisms selected from compost to control soil-borne pathogens

Area of Science:

• Agricultural Science
• Microbiology
• Plant Pathology

Background:

• Compost application is widely studied for suppressing soil-borne plant pathogens.
• Compost efficacy varies due to its diverse composition, sometimes leading to increased disease incidence.
• Selecting microbial antagonists from suppressive composts offers new disease management strategies.

Purpose of the Study:

• To isolate microorganisms from a suppressive compost.
• To evaluate the efficacy of isolated microorganisms against key soil-borne pathogens.
• To explore the potential of compost-derived antagonists as biological control agents.

Main Methods:

• Microorganisms were isolated from a compost derived from green wastes, domestic wastes, and urban sludge.
• Isolates were screened in vitro against Fusarium oxysporum f.sp. radicis-lycopersici on tomato seedlings.
• Promising isolates were further tested in greenhouse conditions against Fusarium oxysporum f.sp. basilica, Phytophthora nicotianae, and Rhizoctonia solani.

Main Results:

• Out of 101 isolated colonies, 28 demonstrated significant disease reduction in laboratory tests.
• Compost-derived Fusarium spp. effectively controlled Fusarium wilts, while bacteria showed significant control against Phytophthora nicotianae in tomato.
• No single isolate effectively controlled all three tested pathogens, particularly Rhizoctonia solani.

Conclusions:

• The compost used in the study exhibits significant suppressive activity against soil-borne pathogens.
• Selecting microbial antagonists from compost is a viable and promising strategy for developing novel biological control agents.
• Further research is needed to develop multi-functional biological control agents for complex pathogen challenges.