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AVOID LOSS: In a survey of 700 U.S. corn farmers, pesticide injury ranked among the top 15 yield loss factors.

Coping with corn yield variability at harvest

Four steps can help avoid pesticide injury to corn plants, which causes yield variability.

The combination of the pest, weed or disease pressures your corn crop faces; the treatments you choose; and the environment into which you apply those pesticides can create a lot of variability in crop growth and development across a field. It all adds up to harvest challenges that call for harvesting equipment that can account for any variability and damage that pesticide injury can inflict on your corn crop.

Minimizing crop variability in the process of effectively treating weeds, pests and diseases is not as simple as it once was, notes Dennis Bollig, who farms near Fenton in northern Iowa. With myriad products on the market, having different modes of action, application time frames and efficacies against various crop issues, it's important to identify your targeted pest pressures. Pay close attention to conditions when applying crop protection products and account for any resulting variability those products can cause in your fields at harvesttime.

"You need to understand the variables that can create any adverse effects on your corn plants,” says Bollig, who is president of Dragotec USA. “Herbicide or pesticide injury can vary across the field. In the process of trying to create uniformity with pesticides, you can also create variability across a field."

Variability in corn growth results in yield loss
In a Dragotec USA survey of 700 corn farmers around the U.S., pesticide injury is among the top 15 yield loss factors, and though it doesn't rank as high as factors like planting delays and moisture extremes, pesticide injury and resulting variability can carry quite a price tag in the form of yield loss.

If you're concerned with yield loss from pesticide injury, follow these steps:

1. Know your pest pressures. It all starts with strong field scouting and knowing not just what issues you face, but whether they're at or beyond economic thresholds. It may be tempting to treat if you see a specific weed or insect pest immediately, but it's important to weigh treatment costs and whether you'll recoup those costs in crop yield.

2. Do your pesticide homework. "You need to read the labels, talk to your chemical reps and agronomists, and find out the best product to apply and understand the variables that product can create in your fields," Bollig says. "Will it create any adverse effects on your corn plants?"

This is a growing concern, he adds, with herbicide resistance growing in some weeds, for example. Other modes of action include growth regulators, pigment inhibitors, cell membrane disruptors and seedling growth inhibitors, and each has unique pesticide injury symptoms that can manifest themselves as yield loss at harvest.

3. Know your mode of action. Different crop protection products have different modes of action that can lead to different types of pesticide injury. ALS inhibitors, for example, can lead to inconsistent emergence or root malformation under certain conditions, both of which can lead to variability and greater yield loss potential at harvest.

4. Treat under the right conditions. When you apply a treatment can be just as important to its efficacy as what you apply. Pay close attention to label instructions, noting conditions like optimal soil moisture, temperatures and general timing to get the most out of what you apply. Failing to apply a treatment under the right conditions can lead to a lot of variability in a crop stand later on. "If your crop is actively growing in an overactive situation versus an environment in which they're stressed and not growing properly, it can cause variability," notes Bollig.

Reacting to variability in growth and yield
Taken together, these steps can help maximize your crop's ability to overcome the pest, disease or weed pressure it's facing without incurring injury from the chemicals you're applying, Bollig says. Doing so can help eliminate the kind of variability that can cause yield loss at harvest.

"It’s all rooted in determining these different factors that create variability based on what we can't control, like the weather," he says. "At harvest, that means accounting for this variability and reacting to it to minimize yield loss. Our Series II and GT corn heads automatically react to every stalk, helping minimize yield loss during harvest. We're all pushing for perfection, but that won't happen. However, our corn heads react better to the variability caused by pesticide injury."

To learn more about how a Drago corn head can help manage variability and minimize yield loss at harvest, contact a local Drago dealer. Or go online to

Source: Dragotec USA


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