Development of plant disease suppressive compost-amended biocontrol agent-fortified potting mixes and turf topdressings and use of random amplified polymorphic DNA markers for identification of Trichoderma hamatum 382

The objectives of this project were to: (1) develop a commercial-scale process for the production of biocontrol agent-fortified compost-amended potting mixes consistently suppressive to several soilborne plant pathogens; (2) assess biocontrol agent-fortified compost topdressings for efficacy in control of dollar spot (Sclerotinia homoeocarpa) on creeping bentgrass cv. "Penncross"; and (3) generate a random amplified polymorphic DNA (RAPD) system for detection and identification of the introduced but indigenous biocontrol agent Trichoderma hamatum 382.;Potting mixes, prepared with various batches of composted softwood bark and/or yard trimmings fortified with the biocontrol agents Trichoderma hamatum 382 (Th382) and Flavobacterium balustinum 299;Efficacy of composted municipal biosolids topdressings fortified with the biocontrol agents Th382 and ;Random amplified polymorphic DNA (RAPD) banding patterns were generated for 65 isolates of T. hamatum, T. harzianum, T. koningii, T. viride and Gliocladium virens, including the biocontrol agent Th382, utilizing a single primer polymerase chain reaction (PCR) assay. Unique RAPD patterns generated with ten random primers differentiated Th382 from other closely related fungi. RAPD patterns were highly consistent for single-spore isolates of Th382. Cluster analysis (centroid method) based on Dice similarity coefficients, revealed great diversity in patterns of isolates of G. virens and Trichoderma spp. including isolates of T. hamatum.