VIEW ARTICLE

Postharvest Pathology and Mycotoxins

Influence of Benomyl and Methyl 2-Benzimidazolecarbamate on Development of Penicillium digitatum in the Pericarp of Orange Fruit. J. W. Eckert, Professor, Department of Plant Pathology, University of California, Riverside 92521; M. J. Kolbezen(2), M. L. Rahm(3), and K. J. Eckard(4). (2)(3)(4)Chemist and research associates, respectively, Department of Plant Pathology, University of California, Riverside 92521. Phytopathology 69:934-939. Accepted for publication 2 March 1979. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-934.

Sporulation of Penicillium digitatum on the surface of decaying oranges was inhibited by superficial residues of benomyl and methyl 2-benzimidazolecarbamate (MBC) resulting from postharvest treatments with wax formulations of the fungicides. Benomyl residues prevented emergence of hyphae from the fruit surface during 2 wk of storage at 20 C, whereas MBC primarily inhibited sporulation of the mycelial mat that formed on fruit after treatment. Penetration of the two fungicides was investigated by (i) microscopic observations of P. digitatum in sections of the peel (pericarp) of diseased oranges, (ii) bioassay of serial sections of peel cylinders from treated oranges for fungistatic activity against P. digitatum, and (iii) measurement of the cross-sectional distribution of radioactivity in the peel of fruit treated with tritium-labeled fungicides. All techniques indicated that benomyl penetrated the peel more efficiently than MBC, forming a fungistatic barrier in the flavedo (exocarp) that prevented eruption of the hyphae of P. digitatum through the epidermis.