If you plant soybeans early, you'll make more money by using fungicide-treated seed - especially when no-tilling into cool, damp soils.

No-till soybeans have been coming on faster than mosquitoes after a wet spell. According to the Conservation Technology Information Center, full-season no-till bean acreage has skyrocketed from just over 3 million acres to 19 million acres since 1990. It's now at 29% of the national total.

That, say agronomists, calls for a focus on fungicides. "All root rot diseases get worse with no-till," points out Ohio State University agronomist Jim Beuerlein. "However, no-till generally produces the best net profit."

Beuerlein recommends the use of Apron plus Rival, or a product similar to Rival, on all early planted no-till soybeans.

"This applies to disease-resistant and disease-tolerant varieties as well as other varieties," he says. "The resistance or tolerance genes don't become active on some diseases, such as phytophthora root rot, until after the plants emerge."

Beuerlein's research has shown a yield boost of up to 5 bu/acre from the use of Apron to prevent phytophthora and pythium with early, no-till planting. And that's on well-drained soils. He says many farmers are planting on heavier soils, with more disease than he has.

"In my experience, you can expect a payback of three or four to one from the use of Apron in areas prone to phytophthora," he says. Rhizoctonia and fusarium are other common seedling diseases. Apron is effective against phytophthora and pythium, while Rival controls several others.

University of Wisconsin seed treatment studies since 1992 have shown soybean yield gains of 4-12% and increased plant stands up to 28%. That's with early planting, narrow rows and no-till or reduced tillage.

All the major seed companies now offer treated soybean seed on request, reports Mark Jirak of Novartis Seed Treatments. A 1995 Novartis survey showed that 9% of the soybean seed was treated with a fungicide. A 1997 survey indicated that it had leaped to 15%.

Don Vance, Lexington, IL, and his farming partners have used fungicide-treated soybean seed for the past four years. "We have seen better stands with treated seed," he reports. "Disease pressure varies from year to year and can't be predicted, but we expect the treatment to pay off long-term."

The hitch with treated seed is that the seed must be planted, Ohio's Beuerlein explains. "It can't be returned. Farmers should take enough treated seed for a high percentage of their acres, but use untreated seed on their latest-planted ground."

Beuerlein recommends that farmers buy treated seed rather than treat their own. "It's critical that it be done correctly," he says. "If possible, get a professional to do the treating."