Planta Med 2008; 74 - PI59
DOI: 10.1055/s-0028-1084965

Activity of a microencapsulated mixture of constituents of essential oils against grey mould and powdery mildew in grapes and vegetables

E Markellou 1, I Vloutoglou 2, VI Mavroeidi 3, A Kalamarakis 1, AL Skaltsounis 4, N Fokialakis 4
  • 1Department of Pesticides Control & Phytopharmacy, Benaki Phytopathological Institute, 8 St. Delta str., 145 61, Athens, Greece
  • 2Department of Phytopathology, Benaki Phytopathological Institute, 8 St. Delta str., 145 61, Athens, Greece
  • 3Ecogen S.A., 1 Karori str, GR-105 51, Athens, Greece
  • 4Laboratory of Pharmacognosy and Chemistry of Natural Products, Faculty of Pharmacy, University of Athens, 15771, Athens, Greece

In an effort to fend off microbial invaders, plants have evolved biosynthetic pathways to produce a variety of products, such as essential oils, that act as natural pesticides. In the current study, the in vivo activity of a microencapsulated mixture of eugenol, thymol and geraniol that are constituents of essential oils against grey mould (Botrytis cinerea) and powdery mildew (Uncinula necator, Sphaerotheca fuliginea) in grape and vegetables was investigated. Wine grape (cv. Agiorgitiko) field trials showed that the mixture, applied curatively close to harvest, was significantly (P=0.05) more effective in reducing B. cinerea bunch rot (43% reduction) than the fungicide iprodione (26%). Preventive spray applications of the mixture to greenhouse grown tomato (cv. Kalisti) had an overall efficacy of 30% under conditions of high grey mould pressure (max 74% infected leaf area on control). However, when the mixture of essential oils was applied curatively the gray mould severity on treated tomato (cv. Optima) plants did not differ significantly (P=0.05) from that of the control. Preliminary studies showed that the mixture did not affect the must/wine quality or the concentration of antioxidants in tomato fruit. In in vitro bioassays, B. cinerea mycelial growth was inhibited by 95% at the concentration of 0.14µg ml-1 (EC95 value) of the mixture. Although the mixture was less effective than wettable sulphur against powdery mildew (U. necator) on wine grape (cvs Merlot, Syrah) leaves, it reduced disease severity on bunches at the same level as sulphur. In greenhouse trials, the mixture had no effect against powdery mildew (S. fuliginea) in potted zucchini (cv. Pepo) plants.

Acknowledgements: General Secretary of Research and Technology of Greece is acknowledged for the financial contribution to the project.