Canadian Forest Service Publications

Formulation of a potential biocontrol agent for Calamagrostis canadensis. 1992. Winder, R.S.; Shamoun, S.F. Phytopathology 82(10): 1155.

Year: 1992

Issued by: Pacific Forestry Centre

Catalog ID: 3264

Language: English

Availability: PDF (download)

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A new Colletotrichum sp. was formulated to enhance virulence on Calamagrostis canadensis (Michx.) Beauv., a reforestation weed in Canada. Conidia were dissolved in a 0.01 M tannic acid solution and rinsed to remove the matrix. In vitro matric inhibition was eliminated; in vivo germination was lacking and coverage was poor. Tween 20 (0.02% v/v) completely inhibited germination, as did skimmed milk. Soy milk and 25% (v/v) Aloe extract did not affect in vitro germination; germination in Aloe extract in vitro was normal but there was no significant damage at rates of up to 1 x 108 conidia m-2. Mycelia from four 10% dextrose liquid cultures or conidia from four potato dextrose agar cultures were incorporated into a 2% (w/v) sodium alginate, 20% (w/v) kaolin clay, and 150 mg streptomycin sulfate/ml solution, solidified in 0.25 M CaCl2, dried and ground. Plants watered until runoff and dusted with 0.01 g m-2 conidial powder exhibited no significant damage. Mycelial dust caused 36 ± 1% leaf area damage (LAD) after 48h dew. This increased to 53 ± 3% when 2% vegetable oil surfactant (VS) was the wetting agent. With 16 h dew, spray until runoff of 132 g/L hyphae in a solution of 0.5% sodium alginate resulted in ca. 30% biomass reduction and LAD after one week. It is possible to combine the liquid formulation with VS and the powdered formulation to attempt further improvement.