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Corn+Soybean Digest

Windshield Scouting Doesn't Cut It

Even with today's rotten prices, there are darn good reasons to scout your soybean fields.

For starters, you need every bushel you can get.

Secondly, the disease challenges are getting bigger as soybean production intensifies. Under Freedom to Farm, soybeans are grown more often on many fields.

So, especially in the Midwest, diseases that were hardly heard of five or 10 years ago, except in small areas of a few states, now rip yields in many fields for many growers. Diseases like white mold, sudden death syndrome and bean pod mottle virus are particularly troublesome.

And many Northern growers have been blindsided by soybean cyst nematode (SCN) because it invaded their fields only recently - or they had it and didn't know it.

Many growers may be taking financial hits of $10,000-20,000 or more per year from SCN, or SCN and a combination of one or more diseases. And diseases are only one reason for scouting, say crop specialists. Checking for nodulation and fertility problems are others.

In the South, insect, weed and disease problems have always been tougher than in the North, but most of the scouting attention went to higher-value crops like cotton. And growers suffer some big losses in soybeans as a result, say crop specialists.

That's why growers need to get more serious about scouting soybeans. So say Duane Berglund, extension agronomist at North Dakota State University, and Jim Hamer, a former extension entomologist at Mississippi State University and now head of Professional Consulting Services, Inc.

"I'd say only 15-20% of growers scout their soybeans the way they should," Berglund says. "The remainder try to get by with checking from behind the windshields of vehicles, or walk a little in fields early on to check on weeds and stands, but not much after that."

If your soybean and total crop acreage have grown to the point you can't find time to scout, then train a family member or hired help or hire a crop consultant, advise Berglund and Hamer.

If you scout yourself, learn to do it right, they say. That means at least weekly scouting during the early season anywhere, and season-long in the South. Many universities put on scouting schools each year, and there are scads of other assistance in the form of weed, disease and insect identification guides in color from universities and some companies, too.

"There are all kinds of assistance available to producers in most, if not all, states where soybeans are grown," says Hamer. "Growers also have access to area and state specialists who will come right to their fields. They just need to think about all of these sources and then utilize them."

Only through regular in-the-field inspections can producers evaluate how their crops are progressing and identify problems early, says Berglund.

So, if you do your own scouting, what are key ways to make it more effective? "Record insect, weed and disease infestations on a map or drawing when you scout through your fields," Berglund advises. "Making an illustrated note of where pests are located will reduce pesticide costs. If one area of a field, or along field margins, is heavily infested with weeds, for example, you can spot spray instead of treating the entire field."

Often, perennial weeds that begin as small patches can be a real challenge to control, especially as weed size increases. Scouting allows detection of weeds in the cotyledon stage - the most economical time for weed management, Hamer says.

Both crop specialists recommend using some sort of measuring device or system when measuring pests of any kind in a field. For example, create a weed map by determining the number and type of weeds per 3' of row, or per square yard, in several randomly selected areas in a field. This enhances precision application of herbicides and often reduces cost, says Hamer.

When monitoring for diseases or insects, and evaluating for treatment, Berglund suggests evaluation on a plant or insect per square yard basis. Start with an infected plant and then inspect the next 19 plants for similar problems. Findings should be recorded as the number of infected plants per 20 or number of insects per plant.

When scouting, cover as much of a field as possible without duplicating your path. Include sections of the field where pest problems are most probable. For example, grassy areas at field margins are a likely place for grasshoppers.

Make inspection stops in at least five places in fields up to 80 acres, adding an extra stop for each additional 25-30 acres.

"Enter a field at different areas each time you scout so sampling locations are varied from previous stops," Berglund suggests. "After a few weeks, much of the field will be inspected. Inspect problem areas during subsequent visits, for as long as the problem persists."

In the South especially, where insects are a far bigger problem, you need a sweep net when scouting to improve the accuracy of information and proper use of economic thresholds, Hamer says. Unless you hire scouting done, you can get all the information on proper insect scouting procedure, and even a source for buying a sweep net, from your county extension office.

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