Author
![]() |
Lakshman, Dilip |
![]() |
Chauhan, Kamlesh |
![]() |
Pandey, Ruchi |
![]() |
CHOUDHURY, BULA - Guwahati Biotech Park |
Submitted to: Biopesticides International
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/23/2017 Publication Date: 6/15/2017 Citation: Lakshman, D.K., Chauhan, K.R., Pandey, R., Choudhury, B. 2017. Evaluation of plant-based antifungal chemicals and control of damping-off caused by Rhizoctonia solani. Biopesticides International. 13(1):21-34. Interpretive Summary: Plants are abundant and renewable sources of natural antimicrobial chemicals and these phytochemicals are receiving increasing attention as broad-based “green pesticides”. Twenty eight plant extracts consisting of essential oils and vegetable oils and 6 chemicals derived from plant essential oils were evaluated for antifungal activity against Rhizoctonia solani, which causes damping-off of economically important plants. Several plant extracts including allylanisole, allylisothiocynate, anethole, anise and lemon eucalyptus oils were found to be potent inhibitors of Rhizoctonia growth in vitro. Selected plant chemicals showing strong antagonistic potential were further tested for control of cucumber seedling damping-off caused by Rhizoctonia. In greenhouse trials, allyl isothiocynate, geraniol, and lemongrass, clove, origanum, pennyroyal, and peppermint oils as soil amendments suppressed damping-off, demonstrating their potential as biofungicides. This information will be useful to scientists developing environmentally friendly disease management strategies. Technical Abstract: Rhizoctonia solani is a soil borne fungal plant pathogen that causes damping-off of economically important crops. This pathogen is generally controlled with fungicides which can be toxic to the environment. Plants are abundant and renewable sources of natural antimicrobial chemicals and their phytochemicals are receiving increasing attention as broad-based “green pesticides”. Twenty eight plant extracts consisting of essential oils and vegetable oils, and 6 chemicals derived from plant essential oils were evaluated for antifungal activity against R. solani using an in vitro poisoned food technique and a hyphal extension bioassay. Several plant extracts including allylanisole, allyl isothiocyanate, anethole, anise oil, and lemon eucalyptus oil were found to be potent inhibitors of R. solani growth in both in vitro assays. Selected plant chemicals showing strong in vitro antagonistic potential were tested for control of cucumber seedling damping-off caused by R. solani. In these greenhouse trials, allyl isothiocynate, geraniol, and lemongrass, clove, origanum, pennyroyal, and peppermint oils as soil amendments at 0.3% (v/w) suppressed damping-off by >70%, which compared well with a commercial fungicide Banrot® 40WP demonstrating their potential as safer disease management alternatives. |