Comparative Efficacy and Systemic Activity of Iprodione and the Experimental Anilide E-0858 for Control of Brown Rot on Peach Fruit. Juan M. Osorio, Former Graduate Research Assistant, Department of Plant Pathology, University of California, Davis 95616. James E. Adaskaveg, and Joseph M. Ogawa. Research Plant Pathologist, and Professor, Department of Plant Pathology, University of California, Davis 95616. Plant Dis. 77:1140-1143. Accepted for publication 25 August 1993. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-1140.

Iprodione, benomyl, or the experimental anilide E-0858 (SC-0858), when used as a pre- or postharvest spray, limited the size of brown rot lesions on fruit of the peach cultivar Elegant Lady inoculated with conidia of Monilinia fructicola. Fungicides applied 21, 14, 7, or 1 day before harvest reduced lesion diameters on inoculated fruit in postharvest storage compared with nontreated fruit. Brown rot lesions on fruit treated with E-0858 were significantly smaller than those on fruit treated with the other two fungicides. Postharvest hydrocooling using chlorinated water after fungicide treatment reduced the efficacy of iprodione or benomyl but not the efficacy of E-0858. Penetration of fungicides into fruit was demonstrated by injecting conidia of the fungus to a depth of 1 cm in fruit that were surface-treated 1–21 days before harvest or 1 day after harvest with E-0858, iprodione, or benomyl. In all treatments, fruit treated with E-0858 had significantly less decayed tissue than nontreated fruit or fruit treated with iprodione or benomyl. When sprays were applied 1 day or 7 days preharvest or after harvest, fruit treated with iprodione had significantly more nondecayed internal tissue than fruit treated with benomyl or not treated. In fruit treated with radioactively labeled fungicide, 51% of measurable radioactivity of ¹⁴C-E-0858 and 2.8% measurable radioactivity of ¹⁴C-iprodione was detected in mesocarp tissue. The remainder of the measurable radioactivity of each fungicide was recovered within 1 mm below the fruit surface. The efficacy of iprodione and E-0858 is attributed to their high activity against M. fructicola and their penetration into mesocarp tissue of peach fruit.

Keyword(s): radioactive fungicide.