Frequency and Pathogenicity of Fusarium spp. Associated with Seedling Diseases of Cotton in Louisiana

Abstract

Over a 2-yr period, Fusarium spp. were isolated from necrotic roots and hypocotyls of field-grown cotton seedlings at a frequency of 42%. Approximately 90% of the Fusarium spp. were identified as either F. solani or F. oxysporum. Other species isolated included F. equisetti, F. moniliforme, and F. graminearum. The different species and isolates within a species varied in virulence to cotton seedlings on the basis of pathogencity tests conducted in the greenhouse. Few isolates caused postemergent damping-off, but many caused root and hypocotyl necrosis and/or death to the taproot. The F. solani isolates were virulent than the other species.