Resistance Management

We have been dealing with the effects of herbicide resistance in agriculture for many years now. In fact, the first case of herbicide resistance in Ontario dates back 60 years to 1957. While this is certainly not a new problem, resistance management has been thrust back into the spotlight in recent times due to the prolipheration of both glyphosate resistant weeds, and multiple chemistry resistant weeds.

As the combines roll through the fields this year, take note of any new weed species that you find in your fields. This is a great time to evaluate how effective your current weed management program is working. As we know the weeds are constantly evolving, so too must our defense against them. Unfortunately, the pace of development of new chemistry has been far surpassed by the rate of resistance development. Even if we had good success with weed management this season, we cannot assume that next season will be the same.

Talking to neighbors, and industry personnel can give you insight into hard to manage species that might be in your area, or soon on their way. The following are just a few of the strategies that should be applied to both combat the advancement of resistant weeds, as well as delay the evolution of new ones.

                Strategic Tillage

                Site-Specific weed management

                Herbicide Group Rotation (not just product)

                Multiple Effective Modes of Action

                Crop Rotation / Diversity 

                Utilization of Cover Crops

                Regular field scouting

                Accurate record-keeping

A multi-faceted approach to weed management is your best defense. Incorporating as many of the tools above into your operation provides the best chance for success in the ever-changing fight for clean crops.

It is important to note that resistance does not only apply to herbicides. Fungicides can also be rendered ineffective due to resistance. Just like herbicides, it is important to rotate modes of action, and ensure product suitability for the target pest. This cannot happen without robust field scouting. Because the life-cycles of common crop diseases are much shorter than weeds, and limited product choices, fungicide resistance has the ability to develop extremely quickly. Extra care should be taken to preserve the efficacy of the products that we currently have, to ensure their usefulness long-term. Unlike a nuisance weed, we cannot hoe a resistant disease out of a field.