Effect of Fungicides on the Occurrence and Growth In Vitro of Basidiomycetes Associated with Superficial Fairy Rings in Creeping Bentgrass. K. E. Kackley, Graduate Research Assistant, Botany Department, University of Maryland, College Park 20742. P. H. Dernoeden, and A. P. Grybauskas. Associate Professor, Agronomy Department, and Associate Professor, Botany Department, University of Maryland, College Park 20742. Plant Dis. 73:127-130. Accepted for publication 25 August 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0127.

Superficial fairy rings (SFR) in turf are incited by several, mostly unidentified, basidiomycetes. The appearance of SFRs has previously been associated with the use of benomyl. Observations at three sites in Maryland and one site in Delaware revealed that SFRs developed in creeping bentgrass (Agrostis palustris) in the absence of fungicide use. Two isolates of basidiomycetes exhibiting similar colony characteristics and temperature optima for growth were obtained from SFRs where benomyl was either not used or was used extensively. Growth of the isolates was not stimulated by incubation at 25 C on PDA amended with 0–100 microng a.i./ml of benomyl, carbendazim, or iprodione. Observations of growth in vitro and in the field do not support the premise that benomyl predisposes turf to SFRs by stimulating mycelial growth.