It pays off to lower your weed seed bank
Preventing weed resistance pays off in the short-term by increasing productivity and ensuring excellent yields from high quality crops, and in the
long term by securing food supplies. A persistent integrated weed management approach limits weed infestation in future, and put weeds off
balance for better yields. Using multiple effective sites of action and lowering the weed seed bank are best management practices to control weeds
and manage resistance.
1. Use multiple effective sites of action in each herbicide application
For years, it was recommended to annually rotate herbicide chemistries. But recent research has shown that simply rotating chemistries doesn't prevent resistance. Using multiple effective sites of action in each herbicide application is the key.
The University of Illinois compared the difference between rotating herbicide chemistries versus multiple effective sites of action in a single
application. They found that when treated with at least two effective sites of action per application, weeds were 83 times less likely to develop
resistance, compared to rotating herbicide chemistries.
The Weed Science Society of America has a herbicide classification numbering system to identify sites of action. Several active ingredients may
have the same site of action, so they share a site of action group number. Becoming familiar with these numbers is a way to ensure multiple sites of action get used.
Also, it’s important to understand which sites of action are effective on a specific weed species. Using a site of action where resistance has
already developed is no better than using a single site of action, which causes resistance.
Use the Take Action Herbicide Look Up Tool to find the site of action group numbers in commercial herbicide brands and begin planning premix or tankmix partners.
2. Start clean and stay clean to reduce your weed seed bank
One of the biggest challenges of resistant weeds is their prolific seed production. Just a few escapes can mean millions of potential viable seeds
in reserve in the soil— the weed seed bank. A single Palmer amaranth plant can produce up to a half million seeds, which can remain in the soil up
to five years.
Managing the weed seed bank is a cornerstone of resistance prevention. It’s also a best practice for protecting crops from weeds. Starting clean
with a residual preemergence herbicide sets the season up for success. It also reduces the impact any emerged weeds may have on yields. Plus,
eliminating weeds with a postemergence herbicide reduces future weeds by suppressing the seed bank.
Want to know more about integrated weed management?
Learn more by visiting the following resources:
Bayer’s global commitment to Integrated Weed Management:
Take Action Site of Action Look Up Tool:
University of Illinois Multiple SOA (83x less likely research):
Purdue University Select-A-Herbicide Tool
University of Illinois Cooperative Weed Management study: