Evaluation of Colletotrichum sp. and Fusarium spp. as potential biological control agents for marsh reed grass (Calamagrostis canadensis)

Abstract Marsh reed grass (Calamagrostis canadensis [Michx.] Beauv.), a plant that limits conifer growth in boreal forest regeneration, was sampled in western Canada for the presence of potential fungal biocontrol agents. Of 20 isolates screened for pathogenicity, Colletotrichum sp., Fusarium spp., and Dilophospora alopecuri (Fr.:Fr.) Fr. were pathogenic to marsh reed grass. Colletotrichum isolate PFC13 caused up to 54% damage when formulated in powdered alginate and applied with a vegetable oil and surfactant combination. The virulence of Fusarium isolates varied with isolate and incubation conditions, while the virulence of isolate PFCI3 was sensitive to formulation conditions. Fusarium isolates had a broad host range, causing up to 78% leaf area damage on marsh reed grass seedlings. Isolate PFC13 had a narrower host range than the Fusarium isolates, including oat, sunflower, and rye, but not other plants such as corn or wheat. Fungi have potential as biocontrol agents of marsh reed grass when considere...