Recent Newsletters

SCN-Resistant Soybean Varieties - 10/17/2012

Profitable soybean yields can be produced in fields infested with the soybean cyst nematode (SCN) by growing SCN-resistant soybean varieties. SCN-resistant soybeans can keep SCN population densities from increasing and produce high yields. Each year, Iowa State University compiles a list of SCN-resistant soybean varieties that are available to Iowa soybean farmers for the upcoming growing season. The list is published with support from the Iowa Soybean Association. The updated version of the publication, titled “Soybean cyst nematode-resistant soybean varieties for Iowa,” is now available for use in planning the 2013 soybean crop.
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Fall Soil Sampling for Soybean Cyst Nematode - 10/12/2012

Now that harvest of this year’s crops is nearly complete in Iowa, it’s time to begin planning for the next growing season. For soybeans, that means taking soil samples to determine SCN population densities. Fall is a perfect time to do this.
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Possible Breakdown of SCN Resistance - 7/28/2012

Iowa farmers produce soybeans profitably in fields infested with the soybean cyst nematode (SCN) by growing SCN-resistant soybean varieties that yield well and prevent large increases in SCN egg population densities. There are hundreds of SCN-resistant soybean varieties for Iowa. Almost all of the varieties contain SCN resistance genes from a single breeding line, called PI 88788. Because of widespread, repeated use of varieties with the same PI 88788 source of resistance, many SCN populations have developed increased reproduction on that type of resistance. It is no longer uncommon to see SCN females on roots of SCN-resistant soybean varieties in the Midwest. How does increased SCN reproduction on soybean varieties with the PI 88788 source of resistance affect soybean yields and the buildup of SCN egg population densities (numbers) in the soil? Results of Iowa State University field experiments reveal the answers.

Symptoms of SCN Damage - 7/23/2012

As if the direct effects of Iowa’s hot, dry growing season on crops were not damaging enough, the soybean cyst nematode (SCN) probably will be more damaging this year than in the past two decades due to the lingering drought conditions.
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Soybean Cyst Nematodes Females on Soybeans - 6/7/2012

The soybean cyst nematode (SCN) is one of the most serious soil-borne pathogens of soybean in Iowa and throughout the Midwest. Juveniles of this microscopic worm hatch from eggs in the spring, then burrow into soybean roots, where they attach to the vascular tissue of the plant and feed. Developing SCN females get progressively larger as they mature, until their fully expanded, lemon-shaped bodies rupture out of the root and become visible on the root surface.
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Spring SCN Soil Sampling - 2/21/2012

Although the soybean cyst nematode (SCN) is one of the most persistent and destructive pests of soybean in Iowa and the Midwest, the potential to underestimate the nematode’s yield-reducing effects is great because damage from SCN is not readily apparent in the field during growing seasons with adequate to excess moisture. The need to take the threat of SCN seriously was recently reviewed in an ICM News article. Fortunately, fields can be checked for the presence of SCN in the spring through soil sampling.
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2012 Season and SCN - 2/20/2012

The soybean cyst nematode (SCN) is one of Iowa’s most serious and persistent soybean pests. The nematode has the potential to cause devastating yield losses, population densities can increase very rapidly within a single growing season, and dormant eggs can survive for more than a decade in infested soils in the absence of soybeans. Random surveys funded by the soybean checkoff in 1995-1996 and again in 2006-2007 revealed that 70 to 75 percent of fields in Iowa are infested with the nematode.
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SCN Control Among Varieties - 1/21/2012

The soybean cyst nematode (SCN) is one of the most damaging pests of soybean in Iowa and throughout the Midwest. The amount of yield loss that occurs is directly related to the SCN egg population densities (numbers) in the soil. Keeping SCN egg population densities from increasing to high levels is needed to maintain profitable soybean production in SCN-infested fields. An effective way to produce high soybean yields and keep SCN egg population densities in check is to grow SCN-resistant soybean varieties.
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Fall Scouting for SCN - 11/11/2011

Plant-parasitic nematodes are microscopic worms that live in the soil and feed on plant roots. Nematodes that feed on corn occur in almost every field in Iowa, but most do not reduce corn yields measurably until they increase to high population densities (numbers). Fall is not a recommended time to check fields for damaging population densities of nematodes that feed on corn. The ideal sampling times and methods for nematodes that feed on corn were discussed in an earlier article in ICM News. The soybean cyst nematode (SCN) is considered by many to be the most damaging pathogen on soybeans in Iowa, the Midwest and the United States. SCN has a very unique biology that allows it to cause great yield loss (greater than 50 percent), to reproduce very quickly and to survive 10 years or more in the absence of a host crop.
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SCN-Resistant Soybean Varieties - 10/21/2011

Growing soybean varieties with resistance to the soybean cyst nematode (SCN) is an excellent way to manage this pervasive and serious soybean pest. Growers have hundreds of SCN-resistant soybean varieties from which to pick. To help Iowa growers sort through all of the possibilities, Iowa State University Extension personnel annually compile a list of SCN-resistant soybean varieties in late maturity group 0 and maturity groups 1, 2, and 3 in ISU Extension publication PM 1649, “Soybean cyst nematode-resistant soybean varieties for Iowa.” This work is supported by soybean checkoff funds from the Iowa Soybean Association.
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