Dr. François Tardif, University of Guelph; Dr. Peter Sikkema, University of Guelph; Ridgetown Campus

In recent years, winter wheat production has increased in Ontario because of new, improved cultivars and increased prices for wheat. Winter wheat is an ideal crop to include in the rotation as it helps to maintain soil structure and breaks
weed cycles.

Pest management is one of the main production costs in winter wheat production. The increase in value and acreage of winter wheat grown in Ontario has made growers more concerned about yield. In order to prevent yield losses due to weeds, herbicides are applied early in the season. Additionally, fungicides are applied to prevent leaf or head diseases. Early herbicide application may occur when night temperatures are low and these conditions have been associated with crop injury. Moreover, in order to reduce the number of applications, producers often spray herbicides with fungicides and/or fungicides with liquid fertilizers. These conditions may cause enhanced crop injury, leading to potential yield losses.

This project aims to determine which herbicides are more prone to causing injuries when applied with fungicides or other additives or when sprayed under cold conditions. It will also help understand the underlying mechanisms behind such injury by examining their physiological basis.

Field trials will be conducted at two sites in Ontario in the 2008-2009 and 2009-2010 crop years. In addition, growth cabinet experiments will be performed at the University of Guelph. It is expected that this project will generate knowledge of which herbicides are more at risk of causing injury when applied under cold temperature conditions and in combination with fungicides and liquid fertilizers. This will provide unbiased and accessible information that can be used directly by growers in decision-making processes and risk mitigation plans. This information could also be used by the agrochemical industry for potential amendments to their product labels and recommendations.