Potential for the Large-Scale Production Of a Biocontrol Fungus In Raw and Composted Paper Mill Waste

The growth and survival of a Trichoderma spp. (Td22) antagonistic to Sclerotinia minor Jagger and Sclerotium cepivorum Berk was studied in raw wood fibre waste (WFW) of paper mill origin and in mature compost of this material. In nutrient-amended, sterilized WFW or WFW compost (both supplemented with 20% w/w millet seed), the biocontrol fungus reached densities in the order of 1010 colony forming units (cfu)/g after 14 days incubation. Lower population densities of Td22 were achieved under non-sterile conditions in the compost:millet mix of between 107-109 cfu/g after 28 days, depending on pretreatment. Viable spore density of Td22 in raw WFW amended with nutrients and 20% w/w millet seed reached approximately 1010 cells/g after 14 days incubation. This study indicates that cellulosic paper mill waste could provide an abundant low-cost growth medium for the large-scale culture of this or other biocontrol fungi.