Yeast - a potential antagonist of stem end rot of mango.
Neeta Sharma, Madhulika Nigam
Author Affiliation: Department of Botany, Lucknow University, Lucknow - 226 007, India.
International Journal of Tropical Plant Diseases 18 : 131-140
Abstract : The yeast Debaryomyces hansenii, isolated from citrus fruit, showed strong antagonistic activity against stem end rot (Botryodiplodia theobromae [Lasiodiplodia theobromae]) in laboratory fruit test. An aqueous suspension of the antagonist yeast cells (109 cells/ml) applied to wounds on the surface of the mango fruit and subsequently challenged with spore suspension of B. theobromae (105 spores/ml) reduced disease incidence by 80-90%. A culture filtrate of the yeast antagonist failed to provide any protection against stem end rot of mango. The pretreatment of antagonistic cells decreased the antagonistic ability of the yeast cells. Under limiting nutrient conditions, the presence of the yeast cells inhibited the growth in culture of the pathogens but the inhibition could be reversed by the addition of nutrients to the medium. Therefore, nutrient competition between the yeast and the pathogen was involved in the mode of action of D. hansenii in reducing mango stem end rot. Moreover, the compatibility of D. hansenii with fungicides made it possible to reduce fungicide concentration while maintaining adequate control.