Resistant weeds, dicamba training, new EPA rules and regulations, and ag companies being bought or merging together have been a few of the topics found in many ag media and publications this winter. In summary, things are continually changing in agriculture and will continue to change. One of those changes that many, if not all growers, have experienced is how to deal with weed resistance. Resistant weed biotypes exist in every field and the only way to prevent or minimize resistant populations is through a program of best management practices (BMPs). This program sets a standard of zero tolerance to keep weeds from going to seed.
In 1996, the first genetically modified soybean was introduced to the U.S. market and since then this herbicide has been a common herbicide used on millions of acres for both corn and soybeans. With the ease of use and effectiveness, early users started to reduce the use rate of glyphosate in an effort to reduce their herbicide cost. Today, over 63% of genetically modified crops grown globally have herbicide tolerance traits. With such a high use of glyphosate on crops globally, weeds have needed to adapt to survive.
Weeds are no different from humans. We adapt to our surroundings, too. Take for example the high use of antibiotics that contributed to the rise of drug-resistant super-germs in the medical field. There are individuals today that are resistant to certain antibiotics - you may even know someone affected. Weeds are the same, they have adapted over time to survive. In so doing there are getting to be more and more resistant weeds across the U.S. Some resistant weeds that have been in the headlines recently have been palmer amaranth, tall waterhemp, giant ragweed, marestail, and kochia to mention a few. See a complete list of herbicide-resistant weeds.
So why do we need a pre-emergent herbicide? Crop production that is profitable starts with a weed control program that includes pre-plant and/or pre-emergence herbicide program that helps deliver a long-lasting residual weed control program. It is vital to stay ahead of the weed pressure. Here are a few key points to consider why a pre-emergent herbicide is needed:
- Slow the development of resistant weeds
- Provides another site of action
- Help reduce early weed competition
- Help improve the effectiveness of your post-emergence herbicides
The good old days are behind us. There are no new herbicides on the horizon that will help fight weed resistance. The use of multiple herbicide programs (fall, pre, and post) is now the wave of the future. Let's be good stewards in all that we do in agriculture for the next generation.