Abstract Description

Botrytis cinerea is a fungal phytopathogen that has an extensive host range, various methods of attack, high genetic diversity, short life cycle and survives prolonged periods. In South Africa it causes significant economic losses in the agricultural sector by affecting table grapes within the vineyard or post-harvest. Fungicides and horticultural practices are enabled to control the growth of B. cinerea. However, the continuous use of fungicides has raised concerns including the development of fungicide resistance, environmental contamination and potential health risks. Furthermore, horticultural practices are labour intensive and not sufficient to control infection. Therefore, alternative methods such as the biocontrol of B. cinerea are being developed. Epiphytic and endophytic microbes are being investigated as potential biocontrol agents (BCA) to control the growth of B. cinerea post-harvest. BCA’s offers a promising alternative to fungicides with no harmful side effects contributing to the quality and safety of agricultural table grapes. Epiphytic and endophytic yeasts and bacteria were isolated from healthy fruits and leaves. As a preliminary screening their anti-B. cinerea activity were tested in vivo on a grape surface. Isolates with activity were subjected to in vitro dual culture assay and identified with 16s rRNA and ITS sequencing. Of a total of 43 isolates only 9 reduced disease severity in the in vivo preliminary screening. Dual culture assays showed greater activity against B. cinerea mycelial plug than its conidial suspension. Furthermore, co-culturing the isolates produced an even greater inhibition. These findings demonstrates the biocontrol potential of epi- and endophytic yeasts and bacteria against B. cinerea.