Efficacy of botanicals in management of blight of gladiolus caused by Botrytis gladiolorum Timm.

Blight caused by Botrytis gladiolorum Timm. causes serious damage to gladiolus under cool and wet weather conditions. Chemical fungicides have been commonly employed to contain the disease. But, keeping in view the hazardous nature of the fungicides, an effort has been made to test efficacy of botanicals against the fungus under in vitro and in vivo conditions. Aqueous extracts of 26 plants belonging to different species were evaluated in the study, of which garlic (Allium sativum L.) and onion (A. cepa L.) were found to be the most promising in inhibiting spore germination of the fungus and holding back severity of infection. Garlic was found to be more effective than onion (red) for control of the disease. The efficacy of garlic was so marked that it had an edge over the fungicide mancozeb (Dithane M-45, 0.2%) which is commonly recommended to control the disease. The efficacy of red onion was at par with the fungicide. The white onion showed lesser efficacy than red onion. On the whole, the studies show that extracts of garlic and red onion hold the potential to contain the disease and may turn out to be suitable alternatives to chemical fungicides.