Antifungal Activity of Essential Oils from Several Medicinal Plants against Four Postharvest Citrus Pathogens

Abstract

Antifungal activity of 25 essential oils, distilled from Moroccan medicinal plants, against Penicillium digitatum, Phytophthora citrophthora, Geotrichum citri-aurantii and Botrytis cinerea is reported. Essential oil from Chrysanthemum viscidehirtum at a concentration of 150 ppm (v:v) strongly inhibited in vitro growth of all four fungi. The other 24 oils reduced fungal development less than 69% at a concentration of 250 ppm. C. viscidehirtum essential oil was further tested on citrus fruits (Citrus reticulata cv. Nules) inoculated with P. digitatum, G. citri-aurantii and P. citrophthora (105 conidia ml-1). The antifungal activity of this oil was weak at 250 ppm, but at 2000 ppm the percentage of decayed fruits was very low. The inhibition data were compared to treatments with the synthetic fungicides procymidone, thiabendazole (TBZ), guazatine and propamocarbe HCL at 1000 ppm. GC-Mass spectrum analysis indicated that C. viscidehirtum essential oil contains ß-farnesene, limonene and many oxygenated sesquiterpenes.