As the potential for Asian soy bean rust increases, so does farmer interest in buying and owning spray equipment, says Mark Hanna, Iowa State University Extension ag engineer.

“Rust has people thinking,” says Hanna. “To be timely you may only have a window of four to five days to spray. So the concern is whether a custom applicator might take too long to get to your field.”

Timeliness is a main reason to switch from custom to private application, agrees Steve Keck, a crop consultant from Plainview, NE. “Farmers who own their own sprayers can pick the best days and the best time of day to spray,” he says. “They can also spot-treat areas that most custom applicators wouldn't.”

Hanna advises farmers to do their homework long before making a decision to use their own equipment or buy new to spray for rust.

“This is a different type of spraying,” he says. “You'll need a small- to medium-size droplet. You'll also more likely need to operate sprayers at higher pressure and gallonage rates than with most postemergence herbicides.”

Spray strategies and equipment that would normally work well to control weeds may prove ineffective to control rust, says Bob Wolf, Kansas State University (KSU) Extension specialist for application technology. He explains that fungicides are typically more challenging to apply than herbicides.

“Fungicides need to be applied uniformly down through the canopy, not just over the leaf surface,” he says. “Keep in mind that the spray droplet sizes required for effective fungicide applications are in the 200-300 micron range vs. the 300-500 micron range typically used for herbicides.”

Accurate calibration is also essential. “There are many challenges in getting equipment set up properly before you can spray effectively,” Wolf says. “Custom applicators are typically better equipped and schooled on how to do that for all types of spray applications, including fungicides.”

Fungicide applications will likely increase wear and tear on pumps, valves, meters, nozzles and other spray equipment. That's because of increased volumes being applied compared to herbicides and increased pressure most likely needed to meet droplet size requirements, says Wolf. Some fungicide formulations may also be more abrasive to the system, he adds.

However, with adequate equipment and know-how, a farmer can be just as successful as a custom applicator might be at disease control, Wolf says.

Crop consultants or field agronomists can also help, especially with questions over disease identification and timing of control. “With soybean rust, it's vital to be able to know where to look and how to identify the disease,” he says.

Equipment costs, however, are probably the determining factor on whether some farmers choose to hire a custom applicator rather than invest in their own spray equipment, says Hanna.

Fifteen to 20 years ago, for example, cost was a major factor that fueled a significant shift in Iowa from privately applied to custom-applied acres, says Hanna.

In Nebraska, most medium-acre farmers — those in the 400- to 800-acre-range — are still using custom applicators, notes Keck. “These farmers just can't afford the investment into bigger, newer machinery,” he says.

Vern Hofman, North Dakota State University (NDSU) Extension ag engineer, agrees that the main drawback to buying a large, modern sprayer is cost. “Most commercial applicators have high-clearance sprayers that sell for $150,000-200,000,” he says. “Farmers who have bought these sprayers have mostly been able to buy them used.”

The total cost to operate a 60-ft., self-propelled boom sprayer is $5.08/acre, according to a newly revised Extension publication titled “Farm Machinery Cost Estimates for 2005,” written by experts from the University of Nebraska and the University of Minnesota. In North Dakota, Hofman says the cost to hire a commercial sprayer is between $4 and $4.50/acre, depending on the farm's location.

“Typically, a custom applicator has more experience and more training than a private applicator,” Hofman says. “Commercial applicators are also used to doing different spray operations. And they take responsibility for spray drift and contamination problems, if and when they occur.”

Hanna says. “It's not just time that you're hiring,” he says. “You're also hiring their expertise and the extra risk they take on.”

Despite the risks, more large-acreage farmers are turning to owning their own spray equipment, says Erdal Ozkan, an Ohio State University Extension ag engineer. “As farmers increase their acreage they don't want to rely on a custom applicator as much because timing is so important,” he says.

Keck concurs. “During the last eight or nine years there's been a shift in more farmers owning their own sprayers,” he says.

That trend may have started even before rust became an issue, Keck points out. “Today's farmers don't spend as much time tilling ground. Instead, more farmers are spending the extra time spraying.”

“It's surprising,” adds NDSU's Hofman, “how many farmers have been buying high-clearance sprayers the last few years.

“You can do the spraying job in a timelier manner. The biggest problem with custom applicators is getting them in your field when you want them,” Hofman says.

Besides better timing and convenience, farmers are also owning their own equipment in an effort to save money, says Keck.

“You can buy cheaper chemicals by not being tied into a custom applicator,” he says. “Chemical shopping might pay back the cost of new spray technology in one or two years.”

Usually, custom applicators will obtain better prices on crop protection products because they can buy them wholesale, Hofman says. “They typically charge their clients more for those products, because they sell them at retail value,” he explains. “So they try to make a little profit on both their service and the products they apply.”

If the weather is too wet for ground application, aerial applicators have an advantage over private applicators, says Hofman. But, he adds, “aerial sprayers don't work as well on hilly topography.”

Ground rigs may have difficulty operating through a heavy plant canopy, and may potentially transfer mold spores around the farm or from one farm to another, points out Wolf. “Airplanes avoid this,” he says, “but there are not enough of them to go around.”

Check These Rust Spray Sites

Advice on how best to control Asian soybean rust continues to develop. For help on how to control the disease and what equipment you'll need, check out these agricultural Extension Web sites: