Bio control of post-harvest horticultural crop disease: Mechanism of microbial antagonists.

Abstract

Introduction In developing country, significant level of post-ha rvest losses has been accounted to decays of fruits and vegetables caused due to fungal attack. It has been estimated that about 20– 25% of the harvested fruits and vegetables are decayed by vari ous post-harvest related fungal pathogens during postharvest handling management operations ( Si gh and Sharma, 2007). These losses are often more damaging in developing countries due to inadequate storage and transportation facilities. Primarily, chemical fungicides are most ly used for controlling decay/diseases causing fungal pathogens of harvested of fruits and vegetab l s. However, excessive use of these chemicals has led to negative impacts of on environ ments, human and animal health’s, development of pesticide resistance in major post-h arvest fungal pathogens and accumulation of toxic pesticide residue in commodities. Due to all these concerns, there is a strong public and scientific desire to seek safer and eco-friendly bi ological alternatives for reducing the decay loss in the harvested fruits and vegetables. Among diffe rent eco-friendly approaches, biological management of fungal decay of harvested fruits and vegetables is an alternative and environmentally safer alternatives. Biological control is the reduction in the populati on or disease/damage causing activity of a pest or a pathogen in its dormant state by one or more organisms that occur naturally or through manipulation of the environment or by mass introduction of antagonists in nature. Postharvest pathogens cause considerable damages to harvested fruits and vegetables during storage and transportation. Synthetic chemic als are mostly used to control losses due to postharvest decay. However, recently, more focus is shifted toward safer and more eco-friendly alternatives for postharvest decays control. Among the various biological alternatives, the use of bacterial antag onistic strain is becoming popular throughout the globe. Several postharvest pathogens ca now be controlled by bacterial antagonists. Several modes of action have be n suggested by which microbial antagonists inhibit the growth of post-ha rvest pathogens. Competition for nutrients and space is most widely accepted mechani sm of their action. In addition, production of antibiotics, direct parasitism, and p ossibly induced resistance in the harvested produce are other modes of their actions by which they suppress the activity of postharvest pathogens.