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Mycoherbicide Product for Broadleaf Weed Control in Turf

by Alan Watson and Stephane Dupont

A collaborative R&D project was started in 1995 to develop a broadleaf weed bio-herbicide for the turf market. Project participants were the University of Guelph, McGill University, the Nova Scotia Agricultural College, Dow AgroSciences Canada Inc., the Saskatchewan Wheat Pool and the BioProducts Centre Inc. The NSERC Technology Partnership Program provided matching funding until the end of 1998. In 1997, MAC1, a fungal isolate discovered at McGill University, emerged from the extensive screening program as the lead organism. Collaborative field efficacy and environmental safety testing were carried out in 1997 and 1998. McGill also developed various test formulations and the industrial partners carried out market and production analyses.

MAC1 is a safe and well-characterized plant pathogenic fungus with narrow agronomic host range, which can be cultured in liquid or solid fermentation. When formulated as a granular product, an application of MAC1 to dandelions in turf results in very rapid control of the weed with no injury to turf grasses. In suitable conditions, lesions develop quickly and a complete kill can be achieved within 7 days. In these conditions, overall activity is often better than Killex® while speed of kill is about twice that of Killex®. The risk of poor performance in hot and dry weather can be minimized through simple use recommendations. The product is compatible with normal lawn maintenance operations such as mowing, fertilization and irrigation. Other broadleaf weeds can also be controlled. Based on a pre-submission consultation with the PMRA (fall 1997) and experimental results, registration should be straightforward.

Preliminary estimations of field, registration and scale-up R&D costs, anticipated production costs, target pricing and market penetration demonstrated good potential profitability, with a recoupment of investment 2 - 3 years after launch. However, expectations of target markets and initial penetration are more in line with those of smaller bioherbicide manufacturers than large multinationals. Thus in 1998, Dow Agro-Sciences decided against taking on the commercial development of the product and withdrew from the project. The Saskatchewan Wheat Pool remains committed to the project and efforts are currently underway to bring new industrial partners into the project.

For further information, contact Dr. Alan Watson, Department of Plant Science, Macdonald Campus - McGill University, 21111 Lakeshore Rd., Ste Anne de Bellevue QC H9X 3V9; tel: (514) 398-7851 Ext. 7858; fax: (519) 398-7897; e-mail:

Separation and Quantitation of the Sources of Dew on Creeping Bentgrass. Williams, D.W.; Powell, A.J. Jr.; Dougherty, C.T.; Vincelli, P. Crop Science 38(6):1613-1617. Compiled by Dr. Ken Carey, Guelph Turfgrass Institute

Many fungal pathogens require free water to cause infections. In high-maintenance turfgrass systems, accumulations of dew are an important source of this water. Little is known about the amount or rate of dew accumulations on turfgrasses under golf course maintenance regimes. Experiments were conducted in 1994 and 1995 to measure separately the different sources of dew as they accumulated throughout the night on irrigated creeping bentgrass (Agrostis palustris Huds.) maintained as a golf fairway. Sources of dew were separated as (i) condensate and (ii) plant-generated moisture (wound exudates plus guttation). Additionally, re-accumulating moisture was measured from original collection sites at 0800h to establish amounts and rates of re-accumulation after displacement, and the optimal time to displace dew to achieve maximum reductions of dew periods. Mean total dew measured at 0800 h over both years was 0.195 mm, 33% of which was plant generated. Moisture re-accumulating following displacement had a higher proportion of plant-generated moisture, ranging from 46 to 77% depending on the time of the observation. Condensate and plant-generated moisture accumulated at similar rates over time. Significant amounts of total dew re-accumulated following displacement prior to 0400 h, indicating that dew displacement prior to that time may be much less efficient at reducing the duration of leaf wetness episodes, regardless of the displacement method used.

Reprinted with permission of The GTI Advisor: Vol. 4, No 11, August 2, 1999

Turf Line News October/November 1999

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