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17 March 2008. Crop Management. Corn Production Considerations University of Illinois at Urbana-Champaign. www.aces.uiuc.edu Urbana-Champaign, Illinois (March 10, 2008)--Most farmers are painfully aware of increases in production costs, whether it is for land, fuel, fertilizer, or other inputs like fungicides. Many have also heard or seen University of Illinois results at winter meetings showing data from university fungicide trials on crops such as corn, soybean, and wheat. If not, Loretta Ortiz-Ribbing, Extension Crops Specialist, Macomb Center, shares some facts and opinions with you.
A summary of university corn fungicide trial results from 12 Midwestern states and Ontario was compiled by Dr. Carl Bradley, University of Illinois Extension Plant Pathologist. In this summary, fungicide applications were profitable 38% of the time (63 out of 168 data points). This summary was based on a $3.50 per bushel market price for corn and a $20 per acre cost for fungicide and application. Based on current prices for corn and fungicide and application costs, the profitability would be similar, ranging between 4.5 and 6 bushels per acre. That means that 62% of the time the fungicide application did not provide an economic benefit, and growers did not recover the cost of the treatment. In fact, in a few cases (27%), a decrease in yield occurred. The bottom line is that in many cases, a fungicide application did not pay for itself when little disease existed in the field and sometimes it resulted in a yield decrease. Let's examine why this might be possible. The obvious reason for a decrease in corn yield is crop injury which was reported in fields around the state when the fungicide application was put on too early. The reason no benefit was seen in many trials was probably related to a couple of factors. One being lack of rain in June which slowed the development of disease causing organisms that resulted in a lack of disease in most fields, and two being the resistance level of the corn hybrid. If the corn hybrid was susceptible to gray leaf spot and any disease was present, one would expect a fungicide application to show a yield response. However, if the hybrid carried moderate to high resistance to gray leaf spot, a fungicide probably would not show any benefit over an untreated control, especially when disease was low or absent, like last year. I would encourage corn growers to persist in asking for corn hybrids that offer a high level of disease resistance and yield. It is an easy way to lower input costs. Another reason for unpredictable results could be an effect of the nature of fungicides and the organisms they are meant to control. Disease causing fungi need to penetrate the leaf surfaces and grow inside the plant in order to cause a disease. Once the fungus has grown into the leaf and starts to reproduce in the plant, many of our fungicides are not quit as effective. So trying to control a fungal disease with a fungicide by a calendar date or aerial application date may not be as effective as scouting and determining if the fungus and corn plant are at the stage needing control. Scouting can also help reduce production costs. Lastly, in 2007, we had a great corn growing season, thanks to Mother Nature. Early in the season, we had good moisture at levels as deep as 72 inches into the soil profile. This encouraged corn plants to establish deep root systems that could help survival and growth during droughty periods. Most areas in Western Illinois and around Macomb also had great growing conditions for corn. Rain fell when it was needed especially during pollination, and lots of sunshine and favorable air temperatures (growing degree days) promoted rapid corn growth. Mother Nature deserves credit for the corn growing conditions and low levels of disease in corn in 2007. This year appears to be off to another good start, as soil moisture levels at depths of 6 to 72 inches are at normal, according to the Soil Moisture Summary for March 1, conducted by the Illinois State Water Survey. However, even though we just experienced the second wettest February on record since 1895, moisture levels in the top 0-6 inches of soil are still 25% below normal in some areas of Western Illinois. This unexpected outcome likely resulted from the frozen nature of our soil which prevented downward movement of water and instead caused water to run off the surface and move downstream, or to evaporate. Let's hope Mother Nature is good for corn production again this year. Loretta Ortiz-Ribbing is the University of Illinois Extension Specialist, and has a doctorate in Crop Sciences and Plant Pathology. Call her at 309-836-8366 or e-mail her at ortizrib@uiuc.edu. University of Illinois Extension provides equal opportunities in programs and employment. Extension programs and materials are research based and strive to meet the needs of people locally. If you need a reasonable accommodation to participate in this program, contact Rick Keim at 217/942-6996. Contact: |
