9.6 Research-Based IWM Successes

For any weed management plan to be successful, there are a few guidelines it should follow and/or address.  Mostly you want to help your crop compete with the weeds.  We will list some concepts here briefly that research is showing are important and will describe them in more detail in later chapters.

• The more variety in your management methods, the better you can keep weeds off-balance and unable to adapt. Dr. Alex Martin, weeds researcher at the University of Nebraska would always say that “the first year you find a weed control method that works really, really well, that’s the last time it is going to work that well.”  The reason is if you keep using it, even the second year, it will not be quite as effective because what you have done is put a little bit of selection pressure on the weed population.   If any germinated weeds happened to survive that particular control mechanism, then you have given them a niche to flourish.  If you change the control strategy the next year, those same weeds no longer have that niche.
• No single weed management plan will be the best for all growing conditions, even on the same field year after year. It is important to be alert and looking at what is happening out in the field ecosystems.  Ecosystems constantly change and you need to prepare to adjust for the next year.
• Weed management plans that not only reduce weed growth, but also weed seed production will result in a reduction of the weed seed bank. This will have long term benefits.
• Prevention was discussed earlier in this chapter and that cannot be emphasized enough. Preventing the weed challenges in the first place is easier and more effective than addressing them once established in the field.
• Eradicating patches of new invasive weeds and herbicide resistant weeds is also important.
• Several chapters will be dedicated to discussing chemical control of weeds, but one key concept is worth highlighting now. Rotating herbicide modes of action is critical when using chemical control methods. Of course before spraying, be sure to scout the field carefully to identify exactly which weeds are problematic.  The crop’s growth stage must also be considered along with the critical period of weed control for the crop and the crop’s tolerance for the weeds present.  Weighing that with your economic threshold will help determine if and when to spray.