A farmer can protect his soybeans from brown spot with fungicide and expect to get about eight more bushels per acre.

But tank mixing the fungicide with an insecticide may make that yield skyrocket.

“Obviously there’s the fungal control that’s really important, but we are also seeing other benefits,” said Andrew Fisher, the fungicide product leader for Syngenta. Research is showing that insecticides will knock down common but potentially destructive insects in soybeans, but mixing in a fungicide allows the plant to thrive at a pivotal point in development.

“We are seeing improved water use efficiency (in soybeans treated with both a fungicide and insecticide) – that really showed up last year – and increasing the photosynthesis as well,” Fisher said.

Soybean trials in Iowa last year showed an eight-bushel increase using fungicide (in this trial, Quilt Xcel), but a near 18-bushel increase with fungicide and insecticide (Endigo ZC).

With soybean prices generally predicted to be high in 2013, farmers may be more likely to invest in inputs, Fisher said.

“Ultimately, it’s showing a really outstanding return on the growers’ investment,” he said.

“What we’ve been seeing is a four to eight bushel increase when fungicide is applied at the R-3 stage,” Fisher said.

The goal is to apply the mix during the R-3 stage, but protect the plant through the all-important R-4 stage.

“We are trying to protect that soybean crop from any stresses at that time. Stresses from insects or disease or Mother Nature can create irreversible yield loss at this time,” Fisher said. “It is the most important stage to protect. We want to maximize our insurance mitigation on that crop.”

New technology is giving the chemicals a longer life in the field – protecting them from breaking down as quickly in the sun – allowing for 15 to 21 days residual effect.

Adding a foliar micro-nutrient to the tank also will help the plant absorb the fungicide, said Keith Garland, a Midwest sales rep for Grasshopper Fertilizer.

With corn prices near record highs the past two years, corn growers in his region have adopted tank mixing, Garland said.

“There are a lot of studies that show that mixing a fungicide with a foliar feed makes the fungicide work better,” he said. Research shows a 12- to 20-bushel increase in corn, he said.

By mid-season, some farmers are starting to question how much more they will spend on inputs, but it’s worth the investment to get the most out of each application, Garland said.

“When you forgo the input cost, you are shorting that crop,” he said. “When you’ve made an investment, you want to keep it moving.”

At $13 or $14 a bushel, a well-treated soybean field might make $130 to $140 more per acre for a fraction of the input costs, he said.

“To me, that investment just makes sense,” Garland said.