Identification and Comparative Pathogenicity ofPythiumspp. from Roots and Crowns of Turfgrasses Exhibiting Symptoms of Root Rot

Pathogenicity of Pythium species recovered from roots and crowns of creeping bentgrass and annual bluegrass was determined under laboratory, growth chamber, and field conditions. Of the 121 isolates of Pythium recovered from diseased roots and crowns, 46 were pathogenic (disease rating 2.0) in laboratory experiments. Of the pathogenic species, P. graminicola was isolated most frequently (18.2% of all isolates), and nearly all isolates tested were highly virulent to creeping bentgrass and perennial ryegrass (...)