Journal of NACAA

Evaluation of a Plant-Based Antimicrobial Formulation on Control of Damping-Off and Other Seedling Pathogens in Vegetable Seedlings

ISSN 2158-9429

Volume 19, Issue 1 - June 2026

Editor: Bindu Poudel-Ward

Abstract

Damping-off disease is a major challenge in greenhouse and nursery vegetable transplant production and can result in significant economic losses due to seedling mortality. The disease is caused by soilborne fungi and oomycetes, including Pythium, Fusarium, Rhizoctonia, and Phytophthora species, and is often exacerbated by environmental stress conditions common in greenhouse production systems. Conventional fungicides are commonly used to manage damping-off; however, concerns about environmental impacts and the development of fungicide-resistant pathogen populations have increased interest in alternative management strategies. This study evaluated the efficacy of a plant-based antimicrobial formulation containing clove oil for controlling damping-off in tomato (Solanum lycopersicum) seedlings under greenhouse conditions. A dilution curve of clove oil concentrations (0.05–0.15%) was evaluated using pathogen-inoculated seedlings with four replicates per treatment. Greenhouse trials were repeated three times to confirm treatment efficacy. Results demonstrated that a 0.05% clove oil concentration provided the most effective disease suppression without causing phytotoxic injury. Higher concentrations resulted in plant injury, while lower concentrations did not adequately suppress pathogen development. Seedlings treated with the 0.05% formulation showed improved survival and reduced disease symptoms compared to untreated controls. These results indicate that clove oil formulations may provide growers with a plant-based alternative to conventional fungicides for managing damping-off in vegetable transplant production systems.