Pre- and post-storage applications of rhamnolipids and cyprodinil + fludioxonil against Aspergillus section Nigri population and ochratoxin A contamination of grapes

Abstract

Grapevines constitute a very important crop in Greece and ochratoxin A (OTA) contamination of grapes is one of the most serious problems. The main aim of this study was to investigate the fungicidal activity of the fungicide Switch 62.5WG (37.5% v/v cyprodinil + 25% v/v fludioxonil) and Rhapynal (80% rhamnolipids) to reduce the black Aspergillus spp. (section Nigri) population and OTA contamination of grapes grown in Greece. Applications with the above products were conducted both at the harvesting stage and after cold storage. The results showed that pre-harvest applications with Switch 62.5WG or Switch 62.5WG + Rhapynal generally reduced the black Aspergillus spp. population, but not the OTA contamination of grapes. However, a repeated application after cold storage further reduced the black Aspergillus spp. population and significantly reduced the OTA contamination of grapes. Generally, this study showed that it is possible to reduce the black Aspergillus spp. population, but not the ochratoxin A contamination of grapes by spray applications with the fungicide Switch 62.5WG. However, fungicide application to grapes immediately after cold storage (2 months) could reduce ochratoxin A contamination of grapes and further reduce the black Aspergillus spp. population.