Investigation of Biological control of post harvest diseases on apple by yeast Metschenikowia pulcherrima

Synthetic fungicides are primary means to control post harvest disease of fruits. The application of fungicides to fruits after harvest to reduce decay has been increasingly curtailed by the development of pathogen resistance to many fungicides and the lack of replacement fungicides. In addition, negative public perception regarding the safety of pesticides and consequent restrictions on fungicide use motivated the search for alternative approach. Biological control of post harvest diseases has emerged as one of the most promising alternative to chemicals. The yeast, M. pulcherrima was evaluated for biological control capability in apple against the post harvest pathogens Botrytis cinerea and Penicillium expansum. In this study, the effect of different treatments of yeast M. pulcherrima was evaluated in challenge with 5×104 or 1×105 spores/ml of B.cinerea and P expansum and effect of pathogen and yeast concentration on yeast biocontrol activity in artificial wounds. However, the growth of B. cinerea and P.expansum on the apple artificial wounds inhibited by washed cell suspensions (1×108 Cell per ml) of antagonism after storage in 1°C and 23°C, But there was no such Inhibition using the same concentration of washed cell suspension of antagonism. The concentrations of antagonist and pathogen spores had significant effects on biological control effectiveness. Culture filtrate of the yeast failed to provide protection against the two pathogens. Population dynamics M. pulcherrima in the artificial wounds was recorded in different time after inoculation at both 1°C and 23°C. M. pulcherrima multiplied rapidly in apple wounds in the present and absence of B. cinerea and P.expansum.