EFFECT OF ERADICATION OF THE ENDOPHYTE ACREMONIUM-COENOPHIALUM ON EPIDEMICS OF RHIZOCTONIA BLIGHT IN TALL FESCUE

The endophytic fungus Acremonium coenophialum was eradicated from selected germ plasms and genotypes of tall fescue by heat treatment or long-term storage (>3 yr) of seed or by fungicide treatment of tillers. This endophyte-free (EF) plant material was then compared with endophyte-infected (EI) plants to assess the progress of epidemics of Rhizoctonia blight in a greenhouse. No significant differences in area under disease progress curve (AUDPC) or AUDPC + area under crop recovery curve (AUCRC) values were detected between EF and EI plants. Two genotypes had significantly lower AUDPC + AUCRC values than other genotypes tested, but the status of endophyte infection had no significant effect on disease progress or crop recovery. In addition, no significant difference in response to Rhizoctonia solani was detected in plants of tall fescue cv. Arid grown from EF seed than from those grown from EI seed.