Commodity Prices and Pests - Allan Vyhnalek Newscolumn Week of May 5, 2008
As I speak with farmers, it is increasingly clear that the higher corn and soybean prices are causing a lot of unintended consequences. It has been well documented that with record income, record expenses are following. How farmers control insect pests will be one management issue that will need to be thought through.
The first thought of the farmer might be – insecticidess and application cost are higher than ever, so I will not apply the pesticide unless I really need to. In other cases, clean-up or preventative applications might be applied to fields because of high commodity prices to head off problems before they start.
Both thoughts make some sense, but may not be the correct way to manage your profit. Using sound Integrated Pest Management (IPM) will still be the best way to make decisions for application of pesticides.
Commodity value is a factor in calculating the economic injury level — the breakeven point whhere the value of potential yield loss from untreated pests is equal to control costs to protect the crop from future injury. As commodity values rise, economic injury levels decrease, if all other variables remain constant.
Extension recommendations often use tables to show how economic thresholds change with control costs and commodity value. In these cases you can simply identify the appropriate economic threshold for your situation. If control costs or commodity values are higher or lower than those in the table, adjust the thresholds accordingly by following the rising or declining trend of the table.
One important exception to this is the economic threshold for the soybean aphid. When the current economic threshold of 250 aphids per plant was developed, it allowed growers a week to apply an insecticide before aphids were likely to increase above the economic injury level (which is much higher than 250 aphids per plant). Midwest soybean entomologists are recommending that even with higher soybean market values, growers should continue to use the economic threshold of 250 aphids per plant. The higher soybean market values mean that growers have a four- to five-day window to treat rather than a seven-day window. One place to lookup information about pesticide thresholds is: http://cropwatch.unl.edu/ .
For more information or assistance, please contact Allan Vyhnalek, Extension Educator, University of Nebraska-Lincoln, Extension in Platte County. Phone: 402-563-4901 or e-mail AVYHNALEK2@unl.edu .
