Gage County
1115 West Scott St.
Beatrice NE 68310
Phone: (402) 223-1384
FAX: (402) 223-1370

News Column

Paul C Hay, Extension Educator

On-board Insecticides

There are two significant developments in corn production in the Southeast Nebraska area. The first has to do with "On Board Insecticides". The United States Environmental Protection Agency (EPA) has completed an in-depth two year review process on Bt corn and registered the process for another seven years. Bt corn has the genetic ability to produce at toxin from a bacteria which is effective in killing certain moth species including European corn borer. European corn borer is the most damaging insect pest of corn in Nebraska. There are two broods of attack each year, one when the corn is about knee high and forming the ear size, and the second during and just after tasseling. Corn borer tunnels not only interfere with water and nutrient flow, they also open the plants to increased attack by fungi, bacteria and other insects.

The review process involved examination of creditable evidence regarding the effects of this technology on humans, environment, and non-target species. What does this mean for Nebraska corn farmers? It means they will continue to have the option of growing Bt hybrids, and will have full access to the main commodity markets for corn. It also means more specific and enforced resistance management requirements. What the EPA is really saying here is that this form of insect control is so environmentally friendly as comparison to other methods that resistance management needs to be stronger part of the regulations.

Growers must plant a refuge of at least 20% non-Bt corn. This may be treated with insecticides as needed to control corn borer's or stalk borers. Options include separate fields, blocks within fields, or strips across fields. External refuges, separate fields must be within ½ mile, 1/4 is preferred, of the Bt field. Strips across the field should be at least six rows wide. Insecticide treatments can only be used on Bt fields when certified necessary by Extension staff or certified crop consultants.

The other major development is a switch to Roundup Ready (RR) corn. We know that resistance or tolerance to Roundup will develop in time. We know it is preferable to alternate usage of Roundup, i.e. use RR soybeans and regular or Clearfield corn hybrids. We know that using RR corn could mean a an additional herbicide treatment in soybeans to control RR corn. So why are we going to see a huge growth of RR corn sales?

It is very hard to find an effective herbicide program which can compete with the low cost offered by the use of RR corn. Several farmers report the per acre herbicide costs in the teens, which is hard to beat. I think as long as that is possible many farmers may ignore the concern over tolerance buildup until it is proven to occur.

I am interested in long term rotations for our dryland producers which will help to avoid these kind of concerns. Planting a wheat or milo crop even 1 year in 4 or 5 years, increases the protection against resistance or tolerance development.

View other Gage County News Columns & News Letters: http://gage.unl.edu/news/news.htm

to Contact our Staff

Extension is a Division of the Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln cooperating with the Counties and the United States Department of Agriculture.
UNIVERSITY OF NEBRASKA-LINCOLN EXTENSION educational programs abide with the nondiscrimination policies of the University of Nebraska and United States Department of Agriculture. We assure reasonable accommodation under the Americans with Disabilities Act.