In vitro study regarding the testing of treatments with inhibiting effect on the pathogenic fungi of Alternaria alternata

This research presents a series of in vitro tests regarding the antimicrobial effects on the A1 and A100 -Alternaria alternate colonies, induced by blue light irradiation, by growth in the presence of the Bengal Pink substance or by the combination of these treatment forms. The in vitro investigations were performed in the laboratory using an experimental device consisted on blue light LED-s and A - alternate colonies were developed in the Petri plates. The Petri plates were incubated at 25-26oC for 7 or 9 days and the diameter of A. alternata colonies was measured daily, starting with the third day after the inoculation moment, in order to monitor the inactivation and inhibition effect of the fungi colonies upon the application of different irradiation doses (2.0J/cm 2 and 2.7J/cm 2 In order to establish the inhibitor effect determined by the simultaneous application of both treatments (blue light irradiation and inhibition with Bengal Pink) two concentrations of Bengal Pink were tested, added directly in the composition of the nutritive PDA (Potato Dextrose Agar - Fluka) medium. Subsequently, the samples cultivated in Petri boxes were irradiated with blue light. Our experimental results demonstrate that the treatment performed in combined form, consisting of both blue light irradiation emitted by LED-s, and growth in the presence of the Bengal Pink substance, induced the best inhibition and inactivation effects on colonies of A. alternata. Our future research will aim at the application of the combined treatment mentioned previously at the level of plants infected with microorganisms of A. alternate and cultivated in protected areas, in view of obtaining ecological harvests meant for the food industry.