The A., with a series of controls and investigations, accomplished on different groups of Oranges and following various forms of artificial infection withPenicillium digitatumandPenicillium italicum, renders evident the different reactions that these moulds have with regard to the resistance of the cuticle and the epidermic and under-epidermic stratums of the peel of the controlled fruits. Moreover the A. confirms that both theP. digitatumand theP. italicumcan act as «parasite of injury» and as «parasite of contact».