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Research:

The Effects of Chemical Treatment, Harvest Date, and Specific Isolation Media on the Peanut Shell Mycobiota of Two Peanut Cultivars. R. E. Baird, Botany and Plant Pathology Department, Purdue University, SWPAP, R. R. 6, Box 139A, Vincennes, IN 47591. T. B. Brenneman, B. G. Mullinix, D. K. Bell, A. K. Culbreath, and J. D. Moore. Plant Pathology Department, Computer Science Department, and Plant Pathology Department, University of Georgia, Coastal Plain Experiment Station, Tifton, GA 31793. Plant Dis. 77:736-741. Accepted for publication 18 March 1993. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-0736.

Peanut (Arachis hypogaea) cultivars Florunner and Southern Runner grown at two locations near Tifton, Georgia, were either treated with the fungicide flutolanil (Moncut) or nontreated. Comparisons of peanut shell mycobiota were made for both treatments at two harvest dates. A total of 12,744 fungal isolates were cultured from 4,200 shells assayed. Over two-thirds of the isolates were Deuteromycotina. Common form-genera isolated were Alternaria, Curvularia, Fusarium, Lasiodiplodia, Nigrospora, Rhizoctonia, and Rhizopus. Isolations of some genera were significantly different between treatments within a cultivar, and between the two cultivars. However, these differences were of small magnitude and inconsistent across farms, harvest dates, or cultivars. In particular, Fusarium, Rhizoctonia, and Nigrospora sphaerica were isolated at significantly different rates from both sites. On Florunner, flutolanil increased total isolations of Fusarium oxysporum, F. solani, and F. equisiti. Also, several Rhizoctonia anastomosis groups (AGs), excluding R. solani AG-4, could be obtained more readily from Florunner than from Southern Runner shells. Mean isolations on three media were significantly different. Rhizoctonia spp. were isolated from shells at the same frequency with tannic acid-benomyl agar (TABA) (semiselective Basidiomycete medium) and malt extract agar (MEA) media. Fusarium spp. were isolated more frequently on malt-salt agar than on MEA and TABA.