Bt Corn Needs a Refuge!

Tracey Baute, Field Crop Entomologist, OMAFRA-Ridgetown and Jocelyn Smith, Research Associate, Field Crop Pest Management, University of Guelph, Ridgetown Campus

Higher corn prices might make it awfully tempting to plant Bt corn on all of your corn acreage. But the price we will pay if corn rootworm or European corn borer develop resistance to Bt technology is far greater than the short term gain you will experience now. If you are planting Bt corn this spring, you need to plant a non Bt refuge. That is the message that the Canadian Corn Pest Coalition (CCPC) and the Canadian Food Inspection Agency (CFIA) are reminding growers about this spring.

Results from phone surveys conducted last summer by the Canadian Corn Pest Coalition indicate that some growers are not in full compliance with the insect resistance management (IRM) requirements set by the Canadian Food Inspection Agency. Failure to comply with these IRM requirements may
lead to insect resistance, may delay the introduction of new Bt technologies and may affect individual grower’s access to Bt technology. To help you better understand all of the IRM requirements for planting Bt corn, the CCPC have developed pocket size cards that contain all of the key information pertaining to IRM and are free to pick up from your local seed dealer this spring.

When you go to pick up your Bt corn seed in the next few weeks, make sure that you are also taking home enough non Bt seed to plant as refuge on at least 20% of your total corn acres for 2008. Where that refuge needs to be planted depends on which type of Bt hybrid you have purchased. So ask your dealer before you leave exactly which Bt hybrids you are planting. If your Bt hybrid only controls European corn borer it can be planted as far as 1/4 mile away from your Bt field. If your Bt hybrid controls corn rootworm or is a “triple stack” that controls both rootworm and corn borer, your refuge will need to go within or adjacent to your Bt field. You should not rely on your neighbours to plant your refuge for you!
Notice from the Canadian Food
Inspection Agency Regarding 2008
Insect Resistance Management
(IRM) Inspection Program

Bt corn products provide producers with an
effective management tool against insect pests
such as European corn borer and corn rootworm.
Proper implementation of Insect Resistance
Management (IRM) plans are necessary to delay
and reduce the potential of insects developing
resistance to Bt crops. For this reason, under the
authority of the Seeds Act and Regulations, the
Canadian Food Inspection Agency (CFIA) authorizes the unconfined release of Bt corn products conditional upon implementation of an IRM plan by the registrants. A key element of the IRM plan is ensuring that Bt corn growers comply with a number of requirements related to refuge planting design and maintenance. As part of a program to verify the proper implementation of IRM strategies by the Bt corn industry, IRM monitoring will be conducted by CFIA inspectors in 2008. Monitoring consists of an interview, a review of the planting records and a field visit. During the field visit, leaf tissue samples will be taken and sent to the CFIA Laboratory in Ottawa for testing. Results of the monitoring across Canada will be pooled and analyzed to give CFIA an overall picture of the IRM compliance rates.

Good record keeping is also a requirement within the IRM strategies. And when we say good record keeping, we don’t mean keeping it all in your head as we are all guilty of doing. Take the time to write down and draw a map of where you’ve planted your Bt corn and non Bt refuge. It will help you to know
where to scout and look for potential problems or signs of resistance as well as your dealers and consultants who may want to come out and check your fields to make sure the Bt hybrids are working for you.

Planting records are also something that CFIA inspectors want to see if they show up to inspect your fields for compliance.

We all have a role to play when it comes to IRM for Bt corn. As part of the on-going monitoring for grower compliance, the Canadian Food Inspection Agency will be sending inspectors out to fields in the summer of 2008 to conduct in-field surveys to determine if growers are complying. This is not new, but given the increase in acres being planted to Bt corn, they too are increasing the number of fields they will be inspecting this year. CFIA has asked that we include a notification of their IRM inspection program in this article which you can find in the text box below.

So let’s make 2008 the year we all get back on track to full IRM compliance and help delay the onset of insect resistance to Bt corn. I don’t think anyone wants to go back to the days before Bt corn was introduced. It is your responsibility to ensure that you do not misuse this valuable pest management tool is available for years to come.

For more information on Bt corn and Insect Resistance Management, visit the Canadian Corn Pest Coalition website at www.cornpest.ca.