As the spread of resistant weeds continues, the term “site of action” is becoming a factor in managing resistance. BASF wants growers to understand herbicide site of action – and what it means to their weed management plan – because it can spell the difference between losing yield or gaining profit.
BASF offers four tips to unlock the benefits of herbicide sites of action:
Know the tool
Site of action is a term used by weed scientists to group or classify different herbicide active ingredients. A critical element in managing or preventing development of herbicide resistant weed populations is employing multiple sites of action during a growing season. Therefore, classifying herbicides by their site of action provides a tool that enables grower and retailers to design an effective weed management program.
“Site of action specifically refers to the biochemical site within a plant where a herbicide has its direct impact on weed growth and development,” said Dan Westberg, Ph.D., BASF Technical Market Manager. “In other words, the site of action is where a herbicide controls a weed.”
Recognize the enemy
The Weed Science Society of America has confirmed 13 different species of glyphosate-resistant weeds across 28 states. Some weeds, such as waterhemp, are developing resistance to multiple herbicide sites of action. Waterhemp, along with its close cousin Palmer pigweed, is especially scary because of its ability to produce at least one million seeds from a single plant. That seed production could result in 6.25 million waterhemp plants in one acre if not adequately controlled with multiple sites of action.
Correct the strategy
First, growers should identify the sites of action for their herbicides. A herbicide’s product label should identify the site of action. If growers are still unsure, they can contact a retailer, herbicide manufacturer, or a crop advisor.
Next, growers should consider application timing. Growers can apply herbicides at multiple times during the season, which enables them to choose from a greater diversity of herbicide sites of action.
Finally, growers can also select tank-mix partners with different sites of action when weather or workload prohibits more than one application during a season to maintain the benefits of a multi-site of action program.
Understand the big picture
Due to resistance, the big picture when it comes to weeds is changing for growers. No single strategy, including herbicide treatment, should be relied upon for weed management.
“BASF is working in the field to provide solutions, technical support and tools to help growers manage weeds based on herbicide best practices,” said Westberg. “One way BASF has done that is by providing the most corn and soybean herbicide sites of action of any crop protection company. But growers should also proactively plan for things like scouting, planning, and cultural and mechanical strategies.”