Weeds are an unfortunate constant in farming. As weed pressures continue and herbicide resistance develops, weed control requires a multistep strategy to be successful throughout the season. Some weeds also bring insects and diseases with them, making it even more important to manage them effectively.

As the new growing season starts, we have checked in with Kendall Pratchler, P&H Agrologist, to talk about how to put together a management plan that fights weeds and helps your bottom line.

Step 1: Know your enemy

The first step for weed management is to know what weeds are on your fields. Your local P&H offers crop scouting services, and P&H agrologists can come to your farm and record the problem weeds that they see, whether they are perennials, annuals or biennials. They can report back to you and recommend an herbicide program, from pre-seed to post-harvest, depending on the crop that you are growing, to keep on top of problem weeds.

Some problem weeds in Western Canada are:

• Kochia
• Wild oats
• Cleavers
• Roundleaf mallow
• Lamb’s quarters
• Wild buckwheat
• Red root pigweed
• Green and yellow foxtail

Farmers in Eastern Canada are seeing the following problem weeds in recent seasons:

• Giant ragweed
• Lamb’s quarters
• Palmer amaranth
• Waterhemp
• Canada fleabane

Step 2: Manage herbicide resistance

Fighting herbicide-resistant weeds is both a short-term and a long-term problem. Weeds such as kochia have had farmers, agronomists, researchers and manufacturers looking for ways to stay ahead and keep them at bay.

There are several ways to tackle herbicide resistance: first again is knowing what you are fighting. Your local P&H can take samples of problem weeds on your farm for herbicide resistance testing to see if they are resistant to the chemicals that you have been applying.

Another way is to add crop rotation to your long-term planning. Crop rotation helps with herbicide resistance because different crops require different herbicides with different modes of action. A wheat/canola rotation may limit your chemical options, while adding peas to the rotation will add a new mode of action into the mix.

An important thing to note is that brand-name herbicides are recommended over generics for a reason.  Generics may provide initial cost savings; however, with multiple players in the market using different formulations, growers may experience varying levels of control, leading to different degrees of acceptance compared to branded products.

Step 3: Round out the team

A strong weed management lineup has other products that help with the efficacy of the herbicides selected for your farm.

Adjuvants can help herbicides stick better onto weeds, especially ones with a waxy cuticle. Some adjuvants also have water pH modifiers to them. Having the right water pH can be critical for the efficacy of herbicides.

Surfactants improve the ability of an herbicide to spread, emulsify, dispense and penetrate to a leaf surface. They also help reduce drift during application.

Tank mix partners also need to be taken into consideration. Glyphosate can add insurance to your herbicide mix. However, if you have glyphosate-resistant weeds, a glyphosate add in product should be considered.

Step 4: Keep the pedal to the metal

Herbicide layering is key to ensuring weed management all throughout the growing season.

Pre-seed and pre-emergent herbicides provide extended weed control right as the season starts. Some farmers apply pre-seed burndown in the fall. Winter snow helps protect the soil and the soil residual herbicide, and the resulting snowmelt in the spring activates the herbicide to control weeds for several weeks at the beginning of the season. Pre-seed herbicides can also be applied in the spring.

Pre-emergent herbicides also help ensure a good start for your crops. There are critical weed-free periods throughout the season, during which it is crucial to prevent issues that may ultimately affect your yield.

In-crop herbicide application keeps your crops protected as they grow and safeguard your yield heading into harvest. Pre-harvest herbicides also promote desiccation to help ready your crops for harvest.

P&H is your partner in weed management. Find your local P&H to get started.