Sometime within the next few months, the Environmental Protection Agency will be making its final decision relating to resistance management refuge requirements for Bt crops. However, some of the refuge mandates being proposed by the federal agency, Delta farm leaders say, could deal an economic blow to the area's farmers.

A difference in viewpoints was starkly apparent in a June 26 visit to Delta leaders by EPA biopesticide officials Phil Hutton and Sharlene Matten at the USDA research complex in Stoneville, Miss.

In what could have been a chapter straight out of the book Men are from Mars, Women are from Venus, the folks from EPA and a group of Delta area farm leaders conversed for hours in two different parallel languages that rarely intersected.

While the two EPA officials stressed the need for increased refuge requirements based on computer modeling results showing possible resistance development at some point in the future, the farmers talked economics.

The federal agency is currently formulating alternative resistance management strategies in order to have something on its books before the Sept. 30 expiration of the current production registration for Bt crops.

EPA officials insist that all possible options are still on the table, but six proposals seem to be receiving the most attention as likely candidates. Among the potential options being discussed are either a 95:5 or a 90:10 ratio of Bt cotton and non-Bt unsprayed cotton; a 95:5 or a 90:10 ratio with the 5 or 10 percent conventional cotton embedded within a Bollgard field or field unit; and an 80:20 or 70:30 ratio of Bt to non-Bt sprayed cotton planted, with the refuge planted within one mile of the Bt cotton.

The proposals represent recommendations from the world of good, better, best, according to Phil Hutton with EPA's biopesticide division. “There is no doubt in anybody's mind that the more refuge you can have, the better off you are if you can afford it, but there are costs. There are operational costs, there are economic costs and there are environmental costs, so these things have to be considered,” he said.

“All of us are under a microscope with this new technology. This technology is under tremendous public scrutiny. And, there are a lot of additional refuge proposals out there — anything from no refuge at all to a 50:50 refuge-to-Bt ratio,” Hutton said. “These proposals are what we've narrowed it down to. These are the most realistic options being considered by EPA.”

Hutton is unsure how long the new registration will remain in effect, but his guess is the more restrictive the Bt refuge requirement the EPA adopts, the greater the length of its regulatory life will be.

While “there is no evidence of field resistance in the five years the product has been in use,” Matten said EPA will design the new refuge requirements to try to avoid what could happen in an effort to preserve the long-term effectiveness of the technology. That means there is a likelihood that growers, based on assumptions made through computer-generated models, could be faced with an 80:20 sprayed option or a 90:10 embedded refuge requirement.

“Are we certain that we need to move in the direction of more restrictive refuge requirements? Well, no. Are we certain it might be the right thing to do? The answer is yes,” said Matten. “There is definitely going to be a move toward more restrictive refuge requirements because we just have too much uncertainty.”

Although the producers in attendance at the meeting were also concerned about resistance management, they were critical of EPA's process of developing new refuge requirements.

“We don't want resistance, but we want to be sure any changes in refuge policy are responsible and necessary,” said Chip Morgan, executive director of Delta Council.

Seymour Johnson, a cotton, corn and soybean producer in Indianola, Miss., urged the EPA to have the field data necessary to defend any resistance management decision it makes to farmers. “Please, if you've got to make a change, be able to defend it and realize the ramifications of what it is going to cost the farmers.

“I think that if you can't explain refuge requirements to farmers, you have a major problem enforcing it because the EPA is viewed as somebody who puts a burden on the farmer unjustly. Sometimes that's true and sometimes that's not true, but I want the EPA to be right when it does something,” he said. “To be right this time, I'd like for the EPA to consider the cost and be able to explain it to the farmer so he can appreciate what you are doing.”

Johnson asked, “Is there proof that it is necessary to add an additional burden to the farmer? We think this is a valuable technology, and we don't want to lose it. But, is it going to be so expensive that farmers decide to opt out of the technology altogether?”

Hutton responded, “We have all of these wonderful models that predict how long the technology is going to go without resistance developing using various scenarios. And, for some like the 95:5 external treated refuge option, the time is just about up, according to the models' predictions. Do we currently have resistant insects? No, we don't. The whole reason we are doing this is to try to prevent that from happening.

“It is possible that what we've been doing is working. It is also possible that the models are correct and right around the corner we are going to begin seeing resistance, and we'll have a big problem,” he said. “You've got to have a model in this case. You use a model when you don't have an existing framework. You can't set up a plot and say, here is the resistance and here is what is going to happen. It would be nice, but we're not there yet.”

The problem, according to Jimmy Smith, Delta Research and Extension Center director, is that all models have weaknesses and make assumptions that are sometimes guesses at best. “Never before have we based decision of this magnitude solely on a model.

“If we had known that these types of decisions were going to be based on models, we would have had a model that we could be working on field-validating at this time. But never in my wildest dreams did I think that these types of decisions would be made on theoretical models without any field validation,” Smith said.

Kenneth Hood of Perthshire, Miss., whose state-of-the-art farm is a haven for researchers testing new varieties and equipment using both models and field testing, said it is his multi-year experience that embedded refuges are totally devastating to a cotton crop. “I am going to tell you right now, there is no way a Mid-South grower can have embedded cotton. The insects will devastate the surrounding cotton acreage and you will have a very serious economic loss.”

Cotton producer Bruce Brumfield of Inverness, Miss., said, “What I'm asking the EPA for is verification before you make me change from 5-percent refuge to 10-percent refuge. We are at the point that we can't lose anymore efficiency and stay in business.”

The major challenge to documenting resistance in Bt crops, USDA entomologist Dick Hardee said, is trying to find with some certainty a very small needle in a very big haystack. “We obviously are not sampling nearly enough insects to even pick up on something. That's why we are changing our techniques. But in the meantime, because we are not sampling enough insects and we do not know for certain whether or not resistance is developing, the only thing we can rely on as far as what might happen are these models.

“From the beginning, I've felt that if there is going to be a problem and it is going to be hard to detect, then maybe we ought to do something in the way of refuge that is acceptable to the grower as logistically feasible and can perhaps satisfy the models along the way,” he said. “At this point, we're just trying to do the best we can to stave off what we think may happen.”


e-mail: Doreen_Muzzi@Intertec.com