BASF issues new call to action in weed management
As the spread of resistant weeds continues, the term site of action is becoming a factor in managing resistance. It is imperative that growers 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.
Here are four tips to unlock the benefits of herbicide sites of action:
Tip #1: 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.”
For example, glyphosate’s site of action is the inhibition of EPSPS synthase; the site of action of Kixor herbicide technology is the inhibition of the PPO enzyme.
Tank mixing these two herbicides provides two sites of action for effective broadleaf weed resistance management.
The development of glyphosate resistance is a good example of the need to rotate sites of action. For the past 15 years, growers have relied almost exclusively on glyphosate year after year to control their weed problems. This practice delivered simple and effective results for many years, but overreliance on one herbicide – and in turn one site of action – caused many growers to develop resistant weed populations. Today, growers have to implement a much more comprehensive management approach, which includes at least two different sites of action in one growing season as recommended by experts.1
Tip #2: Recognize the enemy
Weeds – especially resistant weeds – endanger the very livelihood of growers across the country. They threaten crop-yield potential, valuable input investments and land values.
The Weed Science Society of America has confirmed 13 different species of glyphosate-resistant weeds across 28 states.2 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.3