Anthracnose in Corn on the Increase

        Although it’s been identified for years, Anthracnose in corn seems to be showing up in Wisconsin fields on a more regular basis of late.  Anthracnose of corn may appear as a leaf blight, stalk-rot, top-kill of the stalk, and kernel rot.  However, most damage results from the stalk rot and leaf blight phases.  The anthracnose fungus can attack corn plants at any stage of development.  Symptoms of the stalk rot phase are easy to recognize and usually are not confused with other stalk rot diseases.  Late in the season shiny black, linear streaks and blotches appear on the surface of the lower stalk above the brace roots.  Occasionally, the entire stalk becomes blackened.  The internal stalk tissue or pith becomes discolored, turning dark gray to brown and shredded.  Severely diseased stalks are weakened and are likely to lodge before harvest, which has occurred in many corn fields in 2006.  Anthracnose may develop in the upper stalk above the ear, resulting in top dieback (also common this year).  These blighted tops may top-lodge above the ear.  

        Hybrid selection is the best and first step in disease control. Hybrids available vary widely in their level of susceptibility to anthracnose. Hybrids with some resistance to the leaf blight phase may not be resistant to the stalk rot phase of anthracnose.   Anthracnose severity has reached the point where some companies are going to discontinue offering certain hybrids based solely on their susceptibility to the disease. 

        The anthracnose fungus survives in corn residues.  Interestingly, Wisconsin research does not show an increase in severity with no-till versus conventional tillage.  It’s not exactly known why this is the case.    

Feeding Fresh Corn Silage

        Farm experience has repeatedly confirmed that feeding fresh corn silage (that which hasn’t gone through a full fermentation) usually results in a milk production drop.  For this reason, we’ve recommended having storage facilities that exceed the capacity for one year’s feed needs. 

        In Europe, researchers looked at the effect of corn silage storage time on the digestibility of starch and protein.  Using 15 corn silages ranging widely in dry matter and starch content, they analyzed them every two months beginning at 2 and ending at 10 months.  They found that starch digestibility increased with storage time for each period.  That is, it continued to get better all the way to 10 months.  The increase in starch digestibility was considerable for well-matured corn silage, but almost nothing for corn silage ensiled at less than 30% DM.  Protein digestibility also increased with storage time. 

Soybean Aphid Resistance on the Way

        First discovered in Wisconsin in 2000, the soybean aphid has been a major thorn in the side.  Even in the years when they don’t cause a big problem, there is a lot of time and energy expended just scouting for those little rascals.  It appears that relief may be in sight.  Researchers at the University of Illinois started screening varieties in the USDA Soybean Germplasm Collection for varieties that may have natural resistance.  Sure enough, a few old varieties had such a resistant gene, and it appears to be dominant.  This makes backcrossing into existing commercial varieties relatively easy.   The resistant gene, along with biological control measures, may soon result in the soybean aphid being much less of an in-season management issue.  This is a good example of our USDA tax dollars at work.       

Horsetail:  Is control possible?

        How to kill horsetail (Equisetum arvense)?  Easily recognized as the weed that “looks like a little Christmas tree”, this plant has nerves of steel and is not a welcome site in fields where it gets established.  According to Jerry Doll, retired UW Weed Management Specialist, the list of ways that fail to kill horsetail is much longer than that of ways that succeed.  Eradication may be impossible, but some control is possible with annual tillage and a competitive crop. 

        The extensive and deep rhizome on horseweed means that tillage and cultivation only destroys the top growth and delays reestablishement.  In Canada, researchers hand weeded an area with horsetail 16 times during one summer.  The next year these plots looked identical to the check plot with no control measures. Crop competition with tillage should reduce the infestation more than either practice alone; but still eradication is not likely, even in Roundup Ready crops. One home owner used Roundup three times in one season to kill horsetail: the next year the only weed present was a dense stand of horsetail!  This weed also survived atrazine, even at the 3 to 4 lb/a rates. 

        Chris Boerboom, UW Extension Weed Scientist, reports that researchers in Ontario are having good results with Python applied to field horsetail in the spring. Chris has done a couple strips this year and also reports that results look promising.  In short, this weed is one tough hombre but efforts to find effective control will continue.

EQIP Funding Applications Now Being Taken at the NRCS Office

EQIP is a voluntary conservation program from the USDA Natural Resources Conservation Service.  It supports production agriculture and environmental quality as compatible goals. Through EQIP, farmers may receive financial and technical help with structural and management conservation practices on agricultural land.  

        The list of approved practices eligible for cost sharing is extensive.  Here are just a few: 

·   Grazing practices such as animal lanes, watering systems, pasture establishment, and fencing.

·   Development of nutrient management plans

·   Closure of animal waste storage structures

·   Well decommissioning

·   Conservation tillage practices – mulch till/no-till

·   Forestry practices

·   Conservation practices such as filter strips, grass waterways, stripcropping, and windbreaks 

 A compete list and more information can be obtained from the Fond du Lac County NRCS office (923-3033).