A COMPARATIVE STUDY OF THE ANTIFUNGAL ACTIVITY OF A NATURAL PRODUCT BASED ON ESSENTIAL OILS WITH IMAZALIL AND THIABENDAZOLE ON Penicillium digitatum AND Penicillium italicum

The aim of this paper is to compare the in vitro antifungal activity of an innovative product composed of essential oils, baptized NPP (Natural Plant Protector), which is currently in the testing phase in a Moroccan citrus packinghouse, with the antifungal activity of the two most commonly used chemical antifungals in citrus packinghouses; Imazalil and Thiabendazole, on two isolates of Penicillium: Penicillium digitatum and Penicillium italicum. The minimal inhibitory concentrations (MICs) and the minimal fungicidal concentrations (MFCs) of NPP, Imazalil and Thiabendazole either separately or in combination were determined by the macro-dilution method in malt extract broth. The obtained results showed that both Penicillium isolates were more sensitive to the NPP than the Imazalil and Thiabendazole. In fact, the MIC and MFC values of Imazalil and Thiabendazole for the two Penicillium spp. isolates were high and exceeded the doses authorized by the Moroccan legislation for the treatment of citrus fruits in packinghouses at drencher stage. However, the MIC and MFC values of NPP were lower than the recommended doses by the producer (LIAV) for the treatment of citrus fruits. The combination of the NPP with either imazalil or thiabendazole improved their efficacy on the two isolates of Penicillium spp. These results demonstrated that NPP showed a strong antifungal activity against Penicillium spp. isolates. It can therefore replace Imazalil and Thiabendazole or improve their efficacy in the citrus packinghouse.