Resistance to Benzimidazole Fungicides of Penicillium italicum and P. digitatum Isolated from Packinghouses and Orchards in Egypt. M. A. El-Goorani, Department of Plant Pathology, University of Alexandria, Alexandria. H. M. El-Kasheir, Department of Plant Pathology, University of Alexandria, Alexandria, M. T. Kabeel, Department of Horticulture, University of Cairo, Cairo, and Alia A. Shoeib, Department of Plant Pathology, University of Alexandria, Alexandria, Egypt. Plant Dis. 68:100-102. Accepted for publication 2 August 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-100.

A survey of the incidence and occurrence of strains of Penicillium italicum and P. digitatum resistant to thiabendazole in Egyptian packinghouses and orchards was carried out. About 89% of the P. italicum isolates from decayed fruits treated with thiabendazole were moderately resistant or resistant to the fungicide. In general, P. italicum isolates were more resistant to thiabendazole than P. digitatum isolates. About 19 and 2.7% of the P. digitatum isolates from decayed fruits treated with thiabendazole were moderately resistant and resistant, respectively, to the fungicide. Most P. italicum isolates resistant to thiabendazole showed resistance to benomyl. The P. italicum isolates, with a few exceptions, were sensitive to imazalil or prochloraz. Two isolates of P. italicum were moderately resistant to imazalil, with a minimal inhibitory concentration of about 10 μg a.i./ml. Two additional isolates of P. italicum were moderately resistant to prochloraz, with a minimal inhibitory concentration of about 5 μg a.i./ml. All of these isolates proved virulent.