Farmers who lose corn plants in the first few rows along grassy field borders or grass waterways or grass terraces may have Common Stalk Borer problems. If you are looking for a way to control this insect pest, you need to consider "Option 1" soon. The following recommendations come from Brian Lang, Iowa State University Extension field agronomist at Decorah in northeast Iowa.
Go to the following web site for photos of the problem: http://www.ipm.iastate.edu/ipm/icm/2007/6-4/stalkborer.html Common stalk borer has 4 'timing period' options for management to reduce either "field border" problems, or "in-field" infestations. Option 1 uses a roadside &/or grass-back terrace burn. Options 2 to 4 can be used later in the season if option 1 is not used.
Option 1: This is considered the most complete control option for "field border" infestations. Burn grassy road ditches, grass-back terraces, etc. to reduce "field border" infestations. The recommended time to burn the grass is when the new grass growth is beginning to spike. This timing usually starts in late March. The burn will kill the eggs laid last fall. Actually the grass could have been burned at any time from late fall until now, but spring is the preferred time to minimize exposure to soil erosion.
However, there are some precautions to take before you decide to burn:
1) If roadside crews have established native plantings in your road ditches, it would be harmful to burn these plantings in fall or spring.
2) Be aware of roadside utilities (gas, electrical, communications) that could be damaged and you would be held liable.
3) Pay attention to "no-burn" orders if droughty conditions exist in the county.
4) Be careful of other trash in ditches (discarded oil or gas cans, broken glass, etc.).
Option 2: Apply insecticide during egg hatch -- 575 to 750 growing degree days (base 41, from January 1). "ISU will track degree days and you can find out when we approach these numbers. Often occurs early to mid-May," says Lang.
Option 3: Apply insecticide with an "in-field" herbicide program if perennial grasses and ragweed (populations from last year) are extensive. If larva are in these weeds (quackgrass, wirestem, and giant ragweed) when the weeds are killed with postemergence herbicide, the larva are forced to move out of the weed and into something else such as emerged corn.
Option 4: Apply insecticide during larvae migration -- 1,100 to 1,400 growing degree days (base 41, from January 1). Larva that are too large for a grass stem, leave the grass at this time to find a larger plant to live in (a corn plant). This often occurs around mid-June, but ISU Extension will track the degree days and let you know.
Looking for a few cooperators for Black Cutworm Monitoring
Every spring, ISU Extension sets up a network of Black Cutworm pheromone traps to monitor Black Cutworm moth flights into and across the state. Farmers and agribusiness personnel are welcome and needed to help with the monitoring. Monitoring will begin April 1. Cooperators will be sent a cutworm trap to place, monitor and record the trap results online. If you are interested in cooperating, please contact Adam Sisson by email: [email protected] or phone: 515-294-5899. More information about this is available at: http://www.extension.iastate.edu/CropNews/2012/0228sisson.htm