Farmer interest in Bt corn for 1998 mushroomed beyond expectations. In fact, it went a little crazy.

That was in the cards. The technology had proved its borer-killing power the year before - a near-record year for corn borers. On top of that, devastation was wreaked in non-protected corn in some areas, particularly in the western Corn Belt.

Consider west-central Minnesota. For the third year in a row, unprotected cornfields there were ripped with heavy losses - 20 to 40+ bu/acre in 1997. It was a double-whammy, where two biotypes and great growing conditions combined to produce record losses.

Yield results using Bt corn hybrids under these heavy infestation levels were spectacular by anybody's standards. Farmers and scientists found, however, that even at much lower borer levels, there were yield increases that more than paid for the technology.

University and industry scientists fear the acreage growth rate for Bt corn could slow for '99. The reasons: the extremely low corn prices and the fact that borer levels were low throughout the Corn Belt this year.

As Kevin Steffey, University of Illinois extension entomologist, put it after traveling five states, "Corn borers have been conspicuous by their virtual absence this summer." John Foster, University of Nebraska entomologist, agrees.

"I found one field that was 97% infested, but across the state, after looking at hundreds of fields, it runs from 0 to 3% damage."

Ken Ostlie, University of Minnesota extension entomologist, also reports spotty infestations in western Minnesota, but generally low levels elsewhere.

Nevertheless, these scientists caution growers to not let this year's low corn borer levels prompt them to automatically forego the technology next year.

"Recognizing that Bt populations fluctuate, we simply have to look at Bt corn as insurance, as a risk management tool," notes Ostlie. "In the long run, the technology is definitely projected to pay off - unless we see a reduction of crop prices because production goes up because of Bt, or corn borer populations are squelched because of a large market penetration of Bt corn."

Nebraska's Foster adds: "I remind growers that, in our area, perhaps seven to eight years out of 10, we need some kind of intervention for control of corn borers, especially second- generation borers. We've examined this situation and given all the constraints and the actual cost of the technology, even in a year when the corn price is as lousy as it is now, this technology still pays.

"Sharp growers in our areas who traditionally have more of a corn borer problem have figured out quickly that this technology pays," Foster points out. "One reason this technology has come on so strong is the sound economic basis it has for our growers."

Generally, corn borers are a bigger and more frequent problem in the western Corn Belt than in the eastern Corn Belt. Even so, Illinois' Steffey agrees - mostly.

"In areas where economic infestations of corn borers are relatively frequent, say seven or eight years out of 10, Bt corn is a wise investment," Steffey says. "But in areas where economic infestations are relatively infrequent, say two or three years out of 10, growers should really question whether Bt corn is a wise investment."

The problem is, no one knows for sure whether there will be an economic hit the following year based on incidence the current year.

"Using Bt corn for management of corn borers should be a long-term investment, not a short-sighted tactic used or not used one year based on what happened or didn't happen the year before," Steffey emphasizes. "The correlation between densities one year and the next year usually is not good."

Bruce Burger, a Novartis scientist, seconds Ostlie's comments.

"This technology is essentially a form of risk management," he notes. "Historically, we know we have only about one year out of 10 when we have little or no corn borer damage. So we need to focus on making sure we use that trait to manage corn borers in the future, even though we may not see the benefits this year in every field."

University and industry scientists concur that the Bt gene for protection against corn borer yield loss is "great technology." But Bt won't increase yield potential of a hybrid by even a bushel. It'll only protect the yield potential that the plant offers.

Eric Sachs, team business leader for Monsanto's YieldGard Bt corn, thinks the combination of low corn prices and low borer populations in '98 may slow the adoption rate for '99.

"I think farmers now are mostly reacting to the low corn price, and they have justifiable reasons to be concerned," he asserts. "But, hopefully, that will turn around. It always has, but it's hard when you're going through it."

Most observers feel that the Bt technology will find its way onto millions more acres in the next several years. As best he can estimate, Sachs figures the acreage of Bt hybrids offered by all companies totaled between 15 million and 16 million in 1998 - an awesome accomplishment for essentially their third year on the market.

Paul Bystrak, a Mycogen entomologist, notes: "Bt technology is a whole new deal, and it's an exciting time. The difference with Bt corn, even where growers didn't think they had much of a problem, is quite amazing. I wouldn't be surprised to see this technology get a little cheaper in the future, too, which would make it pencil out a little easier under lower borer densities."

"I still believe this Bt technology will become a megatrend," asserts Dale Sorensen, head of Dekalb Genetics' agronomic services. "There are so many positives to these products. There is the benefit of return on investment per acre, but also it makes management easier for the grower. These benefits can't be measured in dollars and cents. There are environmental aspects as well."

University and industry scientists universally concur that gene stacking of more than one trait in a hybrid or variety is the wave of the future - and is already well under way.

"We have done substantial market research," Sachs says, "and growers are saying they want the corn hybrids they buy to contain several transgenic traits to meet the problems they have on their farms. And that is the goal of all technology providers."

A recent example is AgrEvo's StarLink Bt corn hybrids, which boast a Bt protein with a different site of action from other Bt hybrids. Company officials say it should help prevent possible development of resistance to the technology. It's stacked on top of resistance to Liberty herbicide.

"StarLink technology represents a very important breakthrough in combating the possibility of corn borer resistance to Bt because it contains the Cry9C protein," explains Keith Newhouse, Bt corn marketing manager. "It's also the only Bt that is active against black cutworm in addition to corn borer."

Another stack example: Dekalb Genetics will offer a Roundup Ready-Bt hybrid for '99.