By Shannon Kooima
Integrated Pest Management emphasizes using a diverse set of strategies to mitigate risks based on observations from the field. But as chores go, crop scouting is easier said than done.
In theory, it’s simple to walk your fields, assess what’s happening and make adjustments based on what you see. However, as farms get bigger it’s become a challenge to keep tabs on what’s going on across an entire farm.
When making management decisions, farmers often have no choice but to rely on hired scouts or data provided by the technology that’s part of every new piece of farming equipment. In the modern farm economy, walking fields can almost seem old-fashioned. But for some farmers, scouting is an integral part of a multifaceted approach to monitoring fields. These farmers also find that taking a proactive, rather than reactive, approach to pest management can pay big dividends.
Approaches to pest management
Factors that influence a farmer’s approach to pest management include farm size, location and individual differences in personality or management style. If a farm is large or spread across several counties, doing spot checks in every field might be daunting or impractical; these farmers often hire a crop consultant to do their scouting.
Other farmers rely on the farmer network. They listen to the talk at the coffeeshop or wait until they see neighbors out there with a plane flying over a field and follow suit. Some farmers lean on personal experience. They’ve had good results and go with “the usual,” applying the same inputs every year based on the calendar or plant stage. Others take a more hands-on approach, opting to scout their own fields. These farmers stay attuned to pest activity by closely monitoring insects, weeds and pathogens.
Alison Robertson, Iowa State University Extension plant pathologist, encourages farmers to adopt this more hands-on management style. “I like to say that in those years where you don’t need to spray, you could take your family on a vacation to the Caribbean in the middle of February,” Alison says. “Wouldn’t that have been nice this past winter?”
Practical Farmers of Iowa member Alan Zellmer raises field crops and cattle on his fifth-generation family farm in southwest Iowa. He makes a point to visit every field every seven days, and not just when crops are growing. “Scouting eliminates a lot of surprises, and I think that’s very important,” he says.
Scouting won’t always reduce the number of inputs, but by applying the right tool for the job at the right time, farmers can get more bang for their buck. Erin Hodgson, ISU Extension entomologist, recommends getting into every field every seven to 10 days. “Some insect pests, like aphids, can have exponential growth, doubling populations every two or three days,” she says. “Waiting a month is going to be too late in many cases.”
Similarly, a single waterhemp plant can produce up to 250,000 seeds. With potentially hundreds of plants growing in fields, weed pressure left unchecked can spell big problems. Correctly identifying pests in the field is critical for selecting the correct tools to economically manage the issue.
Diversified rotations reduce pests
There’s no silver bullet to give you a pest-free farm, but experts and farmers agree diversifying your rotation is the single-most effective cultural practice to reduce pest pressure.
“Most of the pathogens we’re dealing with are surviving on residue,” Robertson says. “In a corn-soy rotation, the disease is more likely along the border where a corn-on-soybean field meets a soybean-on-corn field. And once it’s there, it spreads.”
Hodgson adds, “A lot of pests aren’t mobile, they’re host-specific. If that crop isn’t present in the field, it’s a death sentence.”
JUST DO IT: Alan Zellmer regularly scouts his fields to stay ahead of surprises and make more informed management decisions.
For Zellmer, adding cover crops to his corn and soybeans not only reduces disease pressure, but also directly affects his bottom line. He hires an air seeder to get rye on early into standing corn and then no-tills beans into that cornstalk-rye mix the following spring. “We call them ‘rye beans,’” he says. “For the last six or seven years, they’ve dramatically outproduced our conventional beans. I can’t believe it sometimes.”
Many farmers like to scout from the road, but ISU’s Robertson says this is a common mistake that can lead to the unnecessary application of inputs. “It’s important to walk in from the edge where many pests and diseases — like gray leaf spot or northern corn leaf blight — thrive because there’s more light or more grasses,” she says.
“You might end up treating 160 acres for a problem that’s only on the outside edge. Avoiding that requires walking to several different locations within that field. For example, if the field slopes, go to the bottom and compare it to the top. Different things will be going on in the high and low ground.”
To get a representative sample of what’s going on in your field, Zellmer suggests walking in a W shape or a zigzag pattern. “I take random routes across the farm and across the field on an ATV,” he says. “I use my smartphone to take pictures, and if there are any issues, I share them immediately.”
Social media and scouting
Smartphones, social media and other technological advancements make scouting today easier than it’s been in the past. Robertson says crop pathologists are using social media to crowdsource data and rapidly share information.
“Farmers can tweet pictures of what they’re seeing and what county they’re in to @corndisease and @soybeandisease, and the date is embedded. When you see someone in the county next to yours is starting to see leaf spot, you are more likely to head out and scout for it in your own fields,” she says.
“Even without a researcher’s knowledge of the diseases most likely to affect corn in V5 or V6, for example, you can use social media to help you narrow down what you’re looking for, which makes it easier to find.”
Use IPM to adapt
So how can scouting today lead to a healthier bottom line tomorrow? It’s the cumulative learning process and how that affects your decision-making. “Once you get familiar with your fields and are aware of the problems, you can make better management decisions not just this year, but in future years,” Robertson says. “For example, say you have a gray leaf problem. This year, that might mean spraying a fungicide, but next year that might mean choosing a resistant variety so that you no longer need a fungicide.”
While crop scouting helps Zellmer make farm management decisions, he finds that collaboration is ultimately what drives progress.
“At times, we get overloaded with data. One field may receive a considerable amount of green snap and the field right next to it has no difference,” Zellmer says. “Then it’s time to circle the wagons. The combined knowledge of my family, the farmer network, my reps and consultants, and my own experience are how I determine the best path forward. Are there going to be failures? Absolutely. But they won’t strike twice.”
Kooima is strategic initiatives assistant for Practical Farmers of Iowa.