Tag Archives: Soybean Cyst Nematode

Sample this Fall for SCN

Posted on by

Soybean Cyst Nematode (SCN) continues to threaten the profitability of soybean production, regardless of growing conditions. That’s why Iowa State University (ISU) Nematologist Greg Tylka encourages farmers to collect fall samples.

There are two main reasons to collect soil samples for SCN this fall:

  • SCN spreads into new fields every year. SCN is very easy to keep in check when population densities (numbers) are low, and numbers will be low when SCN first becomes established in a field.
  • Growers who have managed SCN with resistant soybean varieties for several years should take soil samples following the soybean crops to determine what the current SCN population densities are and to gauge if SCN egg numbers are increasing on resistant soybean varieties. If fall sampling is done to determine if a field is infested with SCN, it makes sense to sample in harvested cornfields where soybeans will be grown in 2012.

Steps on how to take fall soil samples for SCN are available in the August 18 issue of The Gold Standard by the Iowa Soybean Association. More information about the biology, scouting, and management of SCN can be found at www.soybeancystnematode.info.

Fall Weather is Perfect for Soil Sampling

Posted on by

Now that fall harvest is complete, it’s the perfect time to take a walk in your fields. A recent Wallaces Farmer reminds readers to collect soil samples (1) to determine whether soybean cyst nematodes (SCN) are present, and (2) to develop management strategies to control nematode numbers in those fields that are infested.

“The key to profitable long-term soybean production in SCN-infested fields is to prevent SCN from increasing,” says Greg Tylka, Extension nematologist at Iowa State University. Taking soil samples this fall can help save you money in the long run.

Soil Sampling Guidelines

  • The more soil cores collected and the smaller the area sampled, the more accurate the results will be.
  • Soil cores should be from the upper eight inches of soil.
  • If corn or some other non-host crop was last grown in the field, it doesn’t matter if soil cores are collected in the previous crop’s row.

Click here for the full list of soil sampling guidelines and to read the complete article.

(Source: Wallaces Farmer)

How to Check Fields for Soybean Cyst Nematode

Posted on by

Soybean cyst nematode (SCN) is a small, plant-parasitic roundworm that attacks the roots of soybeans. SCN is widespread throughout Iowa and surrounding states, and can cause as much as 40% yield loss without symptoms appearing on the soybean plants.

Symptoms to Watch For

A recent Wallaces Farmer article highlighted what symptoms to watch for when checking for SCN in your field. Symptoms are usually not apparent when temperatures are moderate and rainfall is adequate to excessive in the growing season. Symptoms generally begin to appear in mid-July and last through the growing season, and include stunting of plants, yellowing of foliage (not just leaf margins or areas between leaf veins) and mid-day wilting.

Dig, Dig, Dig

The only way to check for SCN is to dig roots, gently remove soil from the roots, and look for the egg-filled, round, white SCN females on the roots (see image). Females are about the size of the head of a straight pin or a period at the end of a sentence in a magazine – for most people – females can be seen with the unaided eye. SCN females should be apparent on infected roots through August.

While this is an effective way to identify SCN, it’s also an effective way to see which soybean varieties are controlling nematode reproduction in fields known to be infested. If a soybean variety is effectively controlling the nematode, there should be only 10-20 SCN females present on the roots.

Click here for the full article.

Photo courtesy of Iowa State University Extension.