The Weed Doctor

f you read agricultural literature from decades ago, weeds were managed in major crops using sound crop rotations, cover crops, carefully constructed seedbeds, elegantly designed tillage implements to mechanically control weeds, and judicious use of then-new chemicals called herbicides, which were limited in effectiveness.

Today, modern weed control is herbicide-first, which is instinctively the weed-control tool of choice for homeowners and farmers. The reasons for this paradigm change are not complex: Herbicides bring convenience, simplicity and cost effectiveness to weed control. I consider herbicides to be a modern marvel. However, herbicide-first weed control brings consequences, including a preponderance of herbicide

resis-tant weeds. In conventional agriculture there is renewed interest —almost urgency — to not abandon herbicides but revert to a balanced weed-control strategy for major crops.

In food plots, the instinctive herbicide-first solution prevails, just as it does in conventional agriculture. The consequences of the herbicide-first mindset are the same with conventional agriculture and food plots, along with the need for a balanced weed-management system. However, a balanced weed-control system in food plots is crucial for an additional reason: There are only a few herbicide solutions for weeds in food plots. The diversity in possible weed species infesting a food plot is far greater than the control spectra from available herbicides, and some weeds are simply not controlled. That forces us to take a different approach to successfully manage weeds.

The 10-cent term for a balanced weed-control system is integrated weed management, which is defined as a blended system to manage weeds that’s based equally on cultural, mechanical and chemical weed control. There is not and never has been a prescription for weed control in food plots that will work in all cases. Integrated weed management in food plots is customized, based on knowing the nuances of your forage crop, weeds infesting the site and resources available to manage the infestation. By resources, I mean budget, equipment and time. To take integrated weed management from a concept to an ef-

fective plan for a specific food plot requires careful thought and action. The one-size-fits-all approach does not apply for integrated weed management in food plots, and it never will.

Cultural Weed Control The foundation of an integrated weed-management system is cultural weed control, which captures the innate competitive ability of crops to suppress weeds. Any crop production practice that improves forage growth and the ability of the crop to compete favorably with weeds is cultural weed control. This is also the most cost-effective means to manage weeds. Common forms of cultural weed control include forage crop selection, planting date, seeding rate and soil fertility management (which includes liming). Each of these factors directly affects forage growth and the ability to compete with weeds. Plants, weeds and crops compete for limited resources, such as sunlight, nutrients and water. Weeds obviously cause crop losses because of competition for those limited resources. However, crops can be equally competitive with weeds for the same resources, so why not stack the odds in favor of the forage crop? That’s the basis for cultural weed control. Many of the pre-planting decisions related to establishing a food plot are de facto cultural weed-control decisions. Seek expert advice about what forage species to plant at your location and how to manage those crops for optimized growth. Try to avoid significant deviations from proven forage production guidelines to ensure maximized crop potential.

Cultural weed control is not a stand-alone weed-control practice. It’s the starting point for a balanced weed-management system — the foundation. Even in established food plots, the foundation needs to be repaired. For example, last summer, I frequently advised customers with severe weed infestations to overseed (or frost seed in Northern regions) additional forage seed in the upcoming late winter to rejuvenate the existing forage stand in their food plots. I suspected the stands were spotty or overall sparse, allowing weeds to heavily infest those plots. Weeds are opportunists, and an improved forage stand complements other weed-control efforts. The point to this example is that cultural weed control is more than just the food plot establishment practices. Cultural weed control must be engaged throughout the life of the food plot. (With that said, performing a professional soil test is one of the most important cultural weed control measures you can take.)

Mechanical Weed Control Sometimes the simplest solution is the most effective. This is the case with mechanical weed control, by which weeds are physically cut or removed. The most elementary form of mechanical weed control is simply pulling weeds by hand. This is manual labor in the purest sense; miserable, dirty and physically taxing. In modern times, we can do better than that. Yet my experiences with controlling dog fennel, a tall perennial weed, painfully illustrate that hand-weeding is the only effective method of controlling some troublesome weed species in food plots because of the limitations of other control options.

The most common and practical forms of mechanical weed control are tillage and mowing. Tillage, usually with a disk harrow, destroys weeds while the seedbed is being prepared for planting. If weeds are large, it will usually take two or more passes with a harrow to adequately chop the weeds enough to prevent regrowth. In those cases, harrowing in perpendicular passes enhances the cutting effect. If time permits, repeatedly harrowing seedbeds at biweekly intervals during fallow periods will simultaneously kill emerged weeds and stimulate additional weed seed germination. Repeated at regular intervals through several weeks, this regimen will systematically deplete numbers of viable weed seed in the soil. This is called stale seedbed weed control and is a commonly recommended form of mechanical weed control in food plots.

Mowing is another type of mechanical weed control and a mainstay of food plot management. Mowing is recommended to shred the tops of tall weeds and allow sunlight to penetrate to low growing forages below. To be clear, mowing tall weeds is a temporary, short-term fix, not a stand-alone weed control solution. However, there have been many situations where mowing saved an established food plot from tall weeds and rescued forage productivity — at least for the following hunting season. Although mowing is just a short-term fix, it’s better than abandoning the food plot because of tall weeds. Chemical Weed Control Herbicides are wonderful tools and make weed management easier and more effective. To that end, all of us at Whitetail Institute spend significant time explaining how to use herbicides safely and effectively. Herbicide choices in food plots are limited, and there are some weeds that simply are not controlled by available chemical tools. Further, multi-species forage blends are commonly planted, which limits herbicide use because tolerance varies among forage species. Despite these limitations, herbicides such as Arrest Max for grass control and Slay for broadleaf weed control are frequently recommended and used in food plots. When herbicides are used correctly, they provide a convenient solution with great benefit, which is one reason why the herbicide-first mentality prevails. For all the benefits of herbicides, their overall performance is boosted when used in a balanced system that also uses cultural and mechanical weed control. This is the case in conventional agriculture and food plots. For weeds that can be easily controlled, an integrated weed-management system makes the overall effort more sustainable through time compared to herbicides alone by lessening selection pressure toward herbicide-resistant weeds. For troublesome weeds with few herbicide choices, a carefully crafted integrated weed-management system is the only way to stay ahead of the infestation and protect food plot productivity. ^ For the latest promotions, sales and news visit www.Facebook.com/WhitetailInstitute Vol. 29, No. 3 / WHITETAIL NEWS 41