Canadian Forest Service Publications
Assessment of three fungi as potential mycoherbicides for suppressing Rubus spp. in reforestation sites (Abstract) 1996. Oleskevich, C.; Shamoun, S.F.; Punja, Z.K. Page 96 (Vol. 18(1)) in Canadian Journal of Plant Pathology, Proceedings: The Canadian Phytopathological Society, Annual Meeting. June 25-28, 1995, Toronto, Ontario. Canadian Phytopathological Society, Ottawa.
Issued by: Pacific Forestry Centre
Catalog ID: 4596
Pathogenic fungi isolated from Rubus strigosus, R. parviflorus, and R. spectabilis are under investigation as biological control agents of competitive Rubus weeds in conifer reforestation sites. Inundative doses of mycelia or conidia from three candidate fungi, Phomopsis sp., Colletotrichum sp., and Fusarium sp., caused > 50% damage on detached Rubus leaves. Subsequent tests on intact plants resulted in reduced disease symptoms, therefore trials enhancing fungal survival and virulence by incorporating adjuvants and by host wounding were undertaken. Extensive experiments with Phomopsis and Colletotrichum failed to significantly increase disease despite treatments combining Phomopsis with canola oil and pH adjustments and Colletotrichum with aloe, sucrose, pectin, Rubus leaf filtrate, sodium alginate and kaolin clay, and removal of the conidial matrix. Conidial suspensions of these two fungi in split applications and tank mixes with 1 and 2 mM glyphosate only slightly increased disease symptoms in intact plants. Recently, experiments focusing on F. avenaceum have demonstrated prolific spore production in modified Richard's V8 broth and enhanced foliar lesions when 2% sucrose, 0.5% gelatin and wounding were included. Glyphosate (0.5-1.5 mM) appeared to stimulate spore production and further tests will study the combined effect of F. avenaceum and glyphosate on Rubus under greenhouse and field conditions. As well, investigations into using cell-free extracts (obtained from sonicating F. avenaceum colonized rice) are ongoing.