Make Sure the Cysts Don’t Exist

        Soybean cyst nematode (SCN) has been confirmed in most Wisconsin soybean producing counties.  This pest is a major problem in other soybean producing states and it is likely only a matter of time before SCN reaches that status in Wisconsin.  However, with a keen sense of awareness and some relatively simple testing and control measures, we can delay its impact as a soybean yield robber.   

        The SCN is a small plant-parasitic roundworm that attacks the roots of soybeans.  Plant damage is mainly due to the feeding of females.  The mature females are barely visible, a white dot on the soybean plant root that is much smaller than a nitrogen-fixing nodule.  The white females become yellow as they age and then brown after they die.  The brown stage is the cyst for which the soybean cyst nematode is named. Each cyst contains hundreds of eggs and are moved every way that soil moves: water, wind and farm equipment.  

        Symptoms of SCN infection are often patches of stunted, yellowed, less vigorous plants. However, SCN can cause significant yield loss without causing obvious aboveground symptoms.  The only definitive symptom of SCN infection is the presence of adult female nematodes and cysts on the soybean roots.  The best method of confirming SCN is to test the soil for the presence of SCN.  These tests are offered free of charge through the UW Agronomy Department and the Wisconsin Soybean Growers Association.  Contact the UW  Extension office if you would like to have a sample taken and submitted for testing. 

High risk SCN areas

        Although SCN can show-up anywhere, there are some field areas that will offer a higher likelihood for finding infections.  These include: 

·     near a field entrance

·     areas that have been flooded at one time

·     areas of high soil pH (greater than 7)

·     areas where weed control isn't quite as good

·     areas where the yield seemed to be a little low the last time soybeans were grown

·     along fence lines where wind-blown soil accumulates.  

Management guidelines

        If SCN is detected in a field, crop rotation and resistant varieties are the foundation of a management plan.  SCN populations are significantly suppressed in fields where two or more years of a nonhost crop is planted.  Examples of nonhost crops include corn, small grains and alfalfa.  In addition to crop rotation, there are soybean varieties available that offer effective resistance to SCN.      

Farmer to Farmer Web Site

        A web site has been developed where Wisconsin farmers can list corn (dry or high moisture), corn silage, or hay that they have to sell or would like to buy.  The listings can be searched by county.  If you have internet access, listings can easily be made from your home computer.  There is no charge for this service.  The URL for the web site is: http://farmertofarmer.uwex.edu/ 

Avitec Corn Seed Treatment Update

        With the loss of lindane as a corn seed treatment, growers also lost the only effective means of repelling those pesky sandhill cranes.  As a result, a special use Section 18 permit was granted for the use of Avitec in 2006.  Avitec’s active ingredient is a naturally occurring substance used by plants to repel birds.  The product, applied as a dry powder, was used extensively in 2006 with good overall results.  It was noted that birds will still do some minimal seed sampling until they figure out that other food sources taste a whole lot better.  There were some issues in 2006 with uniform seed application and applying the product along with talc or graphite used for air planters.  Overall, however, the product performed as advertised by preventing large scale planted seed losses.  For 2007, efforts are underway to secure approval for a liquid seed-applied formulation.  This will eliminate the need to apply the product in the seed hoppers.     

High Moisture Corn Inoculants

        Like whole plant corn moisture, grain moisture this fall will be highly variable as well. High moisture corn offers some unique preservation challenges compared to corn silage because it ferments more slowly and less extensively while containing high levels of starch, which promotes aerobic deterioration.  This year’s variability in kernel moisture may add to the problem.  Any aid to hasten fermentation, use up available oxygen, and inhibit yeast growth (once exposed to oxygen) will be beneficial. 

        Standard high moisture corn bacterial inoculants increase the speed of fermentation and reduce dry matter losses.  Aerobic stability during and after feed-out may not be significantly improved with these products and actually may be worse.   

        Lactobacillus buchneri is a unique bacterial inoculant that has been developed to improve aerobic stability of silages by reducing the growth of yeasts.  The net result is that corn inoculated with L. buchneri is more resistant to heating at feed-out compared to untreated grain.  It is a heterofermentative bacteria that produces both lactic and acetic acid during fermentation.  The negative side of using L. buchneri is that it often results in a slightly higher dry matter loss during fermentation and is more costly than standard bacterial inoculants.