Canadian Forest Service Publications
Fusarium as a potential biocontrol agent for competing forest vegetation in conifer reforestation sites in Canada (Abstract) 1998. Shamoun, S.F. 8th International Fusarium Workshop, August 17-20, 1998, Egham, UK. CABI Bioscience, Egham.
Issued by: Pacific Forestry Centre
Catalog ID: 5188
The discovery and development of potential biological control agents to suppress competing forest vegetation (forest weeds) is receiving increased attention in the management of conifer reforestation sites in North America. Development of alternatives to existing forest vegetation methods, such as chemical herbicides and manual brushing, has become important in forest management plans due to economic constraints and increasing public concern over pesticide use. Biological control strategies which utilize microbial organisms or their secondary metabolites to control weeds have been widely investigated in agricultural systems, and similar approaches for pathogen selection, formulation, and application technology could be applied for forests weed management.
To suppress weedy Rubus spp. which compete with young conifers in reforestation sites, a biological control strategy employing indigenous fungi is under investigation. Fungi were isolated from diseased Rubus spp. (R. strigosus, R. parviflorus and R. spectabilis) and evaluated as potential biocontrol agents under greenhouse situation. A candidate Fusarium avenaceum induced moderate to severe leaf areas necrosis to Rubus plants with an inundative foliar applications. Foliar infection increased significantly when F. avenaceum was grown on a rice-grain substrate combined with an organosilicone surfactant (0.4% Silwet L-77) and applied to R. strigosus, R. parviflorus, and R. spectabilis under shadehouse conditions. Extraction and analysis of infested rice filtrates for metabolite production indicated the presence of a single toxin, moniliformin, at levels of 3,300 ppm. Further research is focused on natural selection of F. avenaceum isolates with low levels of mycotoxin and high bioherbicidal properties, improvement of the formulation, determining optimum application technology and screening of F. avenaceum phytotoxins on Rubus spp. using tissue culture techniques. The potential for further development of F. avenaceum as a microbial control agent for weedy Rubus spp. will be discussed.