By University of Illinois at Urbana-Champaign
Expectations of higher corn prices are leading some farmers to neglect
or ignore integrated pest management strategies, and their behavior could
undermine the very technologies that sustain them, University of Illinois
researchers reported at the American Chemical Society meeting in Boston.
Integrated pest management (IPM) is a set of principles developed to
minimize the ecological impacts of pesticides, transgenic crops and other
pest management technologies. A primary goal is to slow the emergence of
?resistant" insects that have adapted or evolved to evade management
strategies that work. Traditional approaches for slowing the development of
insect resistance include crop rotation and scouting for pests to determine
whether and when to use chemicals to limit damage. Newer strategies include
planting non-transgenic corn ?refuges? alongside crops of transgenic corn.

(Transgenic corn hybrids, such as Bt corn, are engineered to produce
toxins that target specific insect pests. Planting refuges of non-Bt corn
near Bt crops slows the development of Bt-resistance in insects.)

The use of corn for biofuels production has pushed corn prices higher
this year than they have been for a long time, said Kevin Steffey, a U. of
I. Extension specialist in entomology and professor of crop sciences.
Steffey is one of three researchers at Illinois to present at the ACS
meeting.

The higher return on the corn crop is encouraging some growers to use
multiple pest management techniques on their crops without first determining
whether they are needed, Steffey said.

?Some people are using chemical inputs when they?re not necessary,? he
said. ?If transgenic corn kills a percentage of corn rootworms, then some
growers will put an insecticide with it to push the percentage higher.?

?They're willing to spend money without challenging why they're
spending money, simply because they can afford it," he said.

Other important strategies are also being neglected or abandoned.
Because non-Bt corn hybrids sometimes yield less than Bt hybrids, some
farmers are doing away with refuges altogether a violation of federal law.
These practices will increase the rate at which target insects become
resistant, Steffey said.

?Some corn growers are looking at short-term gains and ignoring
long-term consequences. This is a mistake repeating itself from the 1960s,?
he said.

Steffey emphasized that most corn growers do follow IPM practices to
control insect pests. But a few are abandoning these practices to boost
profits, he said.

He noted that many growers are too young to remember the crop losses
that occurred after insects became resistant to the powerful, and
environmentally damaging, chlorinated hydrocarbons used in the mid-20th
century. Some growers take the new technologies, such as transgenic corn,
for granted, believing that the problems of resistance will not arise with
these new products.

But resistance is a normal, ecological adaptation to any selective
stress, Steffey said.

?We have an insect, the western corn rootworm, that became resistant
to crop rotation,? Steffey said. ?That made us aware of what we?re dealing
with: This insect is plastic, genetically, and can adapt to a lot of
things.?

Implementing IPM strategies is never a simple task. For example, the
most productive hybrid corn varieties on the market include Bt genes that
are effective against two different insects. Growers want higher yields and
so will buy these ?double-stack? varieties even though one of the insects
the corn is designed to kill may not be a problem in their region, Steffey
said. And since non-Bt corn hybrids often yield less corn than the Bt
hybrids, the growers must be prepared for lower yields from their refuge
corn.

Other factors add to the complexity of the task. In some instances, a
Bt corn that kills one pest can be used as a refuge plant for a Bt corn that
kills another pest. However, the use of ?triple stack? hybrids (which
contain traits for control of corn rootworms and corn borers plus herbicide
resistance) complicates the planning of refuges.

Despite these difficulties, Steffey said, the potential rewards for
corn growers are higher now than ever. And the consequences of ignoring the
hard lessons learned over decades of trial and error could be dire, he said.


[www.rxpgnews.com]