Propolis extract combined with oregano essential oil applied to lima bean seeds against Sclerotinia sclerotiorum

IRENE L CIBANAL; LETICIA A. FERNÁNDEZ; SILVANA A. RODRÍGUEZ; CECILIA N. PELLEGRINI; LILIANA M. GALLEZ

EUROPEAN JOURNAL OF PLANT PATHOLOGY

SPRINGER

Lugar: Berlin; Año: 2022 vol. 164 p. 33 - 43

0929-1873

In this study, propolis extract (PE) and oregano essential oil (OEO), both natural products with different bioactive compounds, were evaluated in vitro and in vivo against Sclerotinia sclerotiorum. This phytopathogen is considered of importance worldwide, as it can infect seeds from many species. Antifungal susceptibility assays on culture media, revealed that PE and OEO were highly active against this phytopathogen, both individually and combined. PE showed a fungistatic effect in a dose-dependent manner, acting mainly through diffusion, while OEO completely prevented the mycelial growth at very low concentrations, with a mixed contribution of vapour and diffusion activity. Outstandingly, OEO was more effective than PE, as their MIC doses were 0.39 µl/mL and 5 µl/mL, respectively. The combination of PE and OEO was favorable, as it caused synergism and additivity in their antifungal activity. In the in vivo experience, dilutions of PE and OEO made in sterile distilled water (SDW) were tested through a pathosystem with lima bean seeds. It was observed that seeds soaked in formulations with 40% PE + 12% OEO + 48% SDW, and 20% PE + 6% OEO + 74% SDW, presented a reduction in disease incidence of 40% and 60% respectively, and a significant decrease of the severity, with a minimum phytotoxic effect. The results of this study strengthens the antifungal action of PE and OEO against S. sclerotiorum, and, as a main goal, indicate the good prospect of using them for the development of biofungicides to protect lima bean seeds from it.