Mitigating herbicide resistance – investigating novel integrated weed management systems

• Term: Five years, beginning in 2016

• Status: Complete (Performance Story)

• Funding Amount: $171,333

• Lead Researcher(s): Breanne Tidemann (AAFC – Lacombe)

• Funding Partners: Alberta Barley Commission (ABC), Alberta Canola Producers Commission (ACPC), Western Grains Research Foundation (WGRF)

Project Description

The best way to reduce weed resistance to herbicides is to use herbicides less often. Chaff collection is a technique that has potential to control weeds and reduce herbicide use. It has been successfully adopted in Australia to help control two of their most problematic weed species - rigid ryegrass and wild radish. In this project, the researchers will evaluate chaff collection in combination with other cultural weed management techniques at several sites to control problem weeds in Western Canada.

Weed resistance to herbicides is increasing rapidly and jeopardizes important herbicide tools. Cropping systems that effectively manage weeds with less herbicide applications are urgently required to decrease the selection for more herbicide resistance and to provide management tools in the face of new resistance issues. This project will evaluate the effectiveness of a harvest weed seed control method known as chaff collection. Chaff collection has the potential to reduce weed populations, and in combination with other weed-suppressing agronomic practices, can preserve the efficacy of herbicides. The researchers will combine chaff collection with some of the best cultural weed management techniques [high seeding rates, winter cereal crops, early-cut silage, perennial forage (alfalfa)] in standard and innovative crop rotations. This study will also for the identification of weed shifts (early selection pressure indicators) that may be associated with the different treatments and rotations we intend to impose. Decreasing herbicide applications in agricultural systems will decrease the selection for herbicide resistant weeds and make producers less vulnerable to losses from herbicide resistant weeds by providing other management methods. Furthermore, any time herbicide use frequency is reduced, there can be positive environment, human health, marketing and societal outcomes.