Postharvest Chemical Control of Penicillium Blue Mold of Apple. B. L. Tepper, Graduate Research Assistant, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061. K. S. Yoder, Assistant Professor, Department of Plant Pathology and Physiology, VPI & SU Fruit Research Laboratory, Winchester 22601. Plant Dis. 66:829-831. Accepted for publication 9 December 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-829.

Apples of six cultivars were selected for uniform size and ripeness, punctured, and inoculated with conidia of benzimidazole-sensitive Penicillium expansum, dipped in fungicide preparations either 4 or 24 hr after inoculation, and stored for 1 wk at 19 C or 11 wk at 0.5 C before decay incidence was rated. Treatment with CGA 64251 was 80% effective at 3.8 µg/ml and 98% effective at 7.5 µg/ml. Benomyl at 300 µg/ml and captan + benomyl at 600 and 300 µg/ml, respectively, were as effective as CGA 64251 at 7.5 µg/ml. Only 38% control was obtained with bitertanol at 900 µg/ml. Fungicide treatments 4 hr after inoculation gave better rot control than treatments applied 24 hr after inoculation. CGA 64251, benomyl, and captan + benomyl controlled rot effectively for the 11-wk storage period. Median lethal doses (µg/ml) for germination of P. expansum conidia on glass slides were: captan + benomyl, 0.07 + 0.07; benomyl, 0.10; CGA 64251, 0.25; captan, 1.04; and bitertanol, 3.98.

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