You don’t like to leave grain in the field. Every bushel on the ground means lost revenue, and you adjust your combine to the “nth” degree to make sure nothing leaves by the back door.

But what if the lost grain didn’t even make it in the front door, or even onto the plant to be harvested? That is exactly what is happening in fields full of Soybean Cyst Nematode, and if you raise soybeans, don’t say that’s not a problem for you.

Think about these statistics:

• 62% of Cornbelt farmers don’t think they have an SCN problem.
• 61% of Cornbelt farmers have an SCN problem.

Review the farm gate posting for October 5, and then let’s move forward. You are being hounded to place your order for seed beans, and if you have not signed the order form yet, make plans to take back your fields in 2007. But you need a strategy.

1. If you are raising soybeans in Iowa, or latitudes accommodating groups 0-3, Iowa State’s new guidebook on SCN resistant varieties is available. It includes a listing for 743 resistant varieties. But after reading the October 5 farm gate posting, you will be appalled to learn only 24 of the varieties have SCN resistance from a source other than PI88788. Iowa State nematologist Greg Tylka says, “The percentage of SCN-resistant soybean varieties with resistance other than PI88788 is 3% for the 2007 growing season; that’s down dramatically from 15% of 586 SCN-resistant soybean varieties in 2004.”
2. If you are raising soybeans in Illinois, a similar listing for SCN resistant soybean varieties is available from University of Illinois Extension.
3. For SCN information specific to other states, visit the SCN website.

If you are among the 62% of Cornbelt farmers who don’t think they have a problem with SCN, and in the 61% that do have a problem, then you might consider getting a new type of soil test that identifies the degree of seriousness of your problem. Iowa State’s Greg Tylka says, “Soybean growers who have experienced sub-par yield performance from SCN-resistant soybean varieties in SCN-infested fields should consider having an HG type test conducted. Also, if numerous SCN females are observed on the roots of SCN-resistant soybean plants during the growing season, an HG type test probably is warranted. Soybean growers who have grown SCN-resistant soybean varieties in SCN-infested fields numerous times in the past might consider having an HG type test performed, too.”

The HG test essentially uses your soil to grow soybeans in a greenhouse, to allow specialists to accurately determine how many SCN females have developed in 30 days of incubation.

• Two gallons of soil are needed to conduct this test. The results of the test will be only as good as the quality of sample collected and submitted.
• To get meaningful results, the sample submitted needs to be representative of the area of interest (usually an entire field).
• The sample must contain soil collected from throughout the area sampled, not just from one spot in the area.
• Soil should be collected to a depth of 6 to 8 inches from 20 to 40 locations throughout the area being sampled.
• All of the soil should be combined and submitted for the HG type testing.

As you write your check for 2007 seed beans, consider if you are assigning part of your revenue to soybean cyst nematode. If that is revenue you can’t afford to sacrifice, then ensure you are managing your production risk by selecting seed that gives you a chance to make money in 2007 by minimizing your SCN risk.

Summary:

While most farmers don’t think they have a soybean cyst nematode problem, they really do; because most of the seed we plant comes from a single source of resistance, which is quickly breaking down. The way to ensure you harvest all potential revenue from soybeans, and not leave unharvested bushels in the field is to vary your source of resistance by booking different seed. Secondly, avail yourself of the new HG test at a university or independent testing laboratory.

Stu Ellis