Forestry Canada

Her Majesty the Queen in Right of Canada, As Represented by the Minister of Natural Resources, Canadian Forestry Service

Richard Scott Winder

Jeffery Jerome Wheeler

Microparticles such as propagules of eukaryotic biocontrol agents are encapsulated in cellular-scale polymer capsules that have a diameter similar to normal eukaryotic cells in a range of about 10 &mgr;m to about 400 &mgr;m. The microparticles are encapsulated by adding a hydrophobic dispersion medium such as a mixture of chloroform and hexane or a mixture of corn oil and n-hexadecane having a specific gravity of about 1 and containing an emulsifier such as lecithin to an aqueous suspension of the microparticles and a polymer matrix precursor such as alginate, agitating vigorously to form a stable emulsion of microscopic globules containing a microparticle, and adding the emulsion to an aqueous solution containing a polymerizing agent such as calcium chloride to polymerize and precipitate the globules to form microparticles encapsulated in polymer matrix capsules that may be of a teardrop shape having a length of 40-200% longer than the diameter. Precipitation of the globules is regulated by substantially matching the Specific Gravity of the hydrophobic dispersion medium and the aqueous suspension. The microparticle may be a viable propagule of a weed pathogenic fungus to provide a herbicidal composition.

Encapsulation of microparticles in teardrop shaped polymer capsules of cellular size

The mycoherbicide of the present invention is effective in the control of Calamagrostis canadensis and/or related grasses, particularly in areas undergoing reforestation. The mycoherbicide includes one or both of Fusarium nivalis (ATCC #26050) and a fungus, Colletotrichum calamagrostidis (PFC-215, ATCC #74287), isolated from a diseased plant of C. canadensis var. canadensis. The mycoherbicidal formulation preferably includes an allelopathic agent, such as straw, straw-based material, straw extract, grass extract or an endophyte. An especially effective treatment was demonstrated with C. calamagrostidis (PFC-215) and an inoculum of endophytic Fusarium nivalis. An embodiment of a method of treatment according to the present invention includes the application of endophytes of reduced virulence to grass bordering a target area or in grazing lands, to prevent either natural or inoculative infection.

Growing community of inventors

Sooke, Canada

Richard Scott Winder