Weed Control News

Mycoherbicide for Broadleaf Weed Control in Turf

A fungal isolate discovered at McGill University in 1997 has been found to be a highly effective and environmentally safe control for several broadleaf weeds. This isolate emerged from an extensive screening program in a collaborative project including three Canadian universities, Dow AgroSciences Canada Inc., and other ag groups to develop a bioherbicide for the turf market.

This isolate, MAC1, is a well-characterized plant pathogenic fungus with a narrow agronomic range. It can be cultured in liquid or solid fermentation. A single application of a granular formulation of MAC1 to dandelions in turf results in very rapid control with no injury to the grass. Lesions develop quickly and the plant can be killed within 7 days when conditions are suitable. In these conditions, overall activity is often better than the herbicide Killex and the fungus kills the plant twice as fast as the herbicide. The product does not perform well in hot and dry weather, but efficacy under these conditions can be improved by following some simple recommendations. Other broadleaf weeds besides dandelions can also be controlled, and the product is compatible with normal lawn maintenance practices including mowing, fertilization and irrigation.

This product is not registered yet in Canada or the U.S. In 1998 Dow AgroSciences decided against taking on the commercial development of the product and withdrew from the project. Although potential profitability appears good, expectations of target markets and initial penetration are more in line with those of a smaller bioherbicide manufacturer. The wheat growers group in Saskatchewan is actively searching for new industrial partners to hopefully bring this product to market.


Watson, A. and S. Dupont. 1999. Mycoherbicide product for broadleaf weed control in turf. Pest Managment News 10(4): 6.

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