Pesticide Perceptions

2,4-D Launched Herbicide Revolution, But Impeded Other Weed
Research

It was spectacular, economical, a miracle.  That's what farmers
thought of the weed killer 2,4-D when it was developed by U.S.
scientists in the mid-1940s.

"The fantastic success of 2,4-D led to the herbicide revolution
and it was to good to be true," says Orvin Burnside, a weed
scientist at the University of Minnesota.  "When 2,4-D was first
used it was so successful that we concentrated our weed
management research and education programs on herbicide
technology.

"We'd expect industry to concentrate on herbicide development
because of the profit incentive.  And when public sector
scientists also jumped on the herbicide bandwagon we created a
lopsided weed management system in the U.S..  But now it's time
to regroup and develop alternatives and supplements to
herbicides," says Burnside, who addressed the North Central Weed
Science Society's annual meeting Dec. 5, 1995 in Omaha, Neb.

"Weed control should now move from a largely chemical approach to
a systems approach, preventive, mechanical, cultural, biological,
chemical and integrated strategies.  We should not abandon
herbicides, but we can use them more judiciously as we
incorporate alternative weed management technologies.

"Water quality and other environmental standards must be met or
exceeded," he said.  "We need to conserve natural resources such
as soil and fossil fuels while increasing productivity,
profitability and competitiveness of U.S. agriculture. 
Implementing alternative weed control methods, not more programs,
is the way to solve herbicide contamination of ground and surface
water.

"The one thing I have learned from 35 years of weed research is
that there's no panacea weed control method," Burnside said. 
"You never get rid of weeds, some have survived every control
method yet devised by humankind.  That's why we need a more
integrated approach to weed management."

Research needs include weed biology and life histories, weed
seedbanks, seed and bud dormancy, cover and smother crops with
different life cycles, weed competitive crops, biological and
ecological weed management.  Others are postemergence herbicide
technology, precision herbicide applications, environmentally
benign herbicides, reduced-tillage crop production and
environmentally safe weed management methods.

And, Burnside said we may lose one-half of our present herbicides
in 1997, when all pesticides registered before 1984 must be re-
registered by the Environmental Protection Agency (EPA) or lose
their registrations.  "If we lose 2,4-D and other phenoxy
herbicides, weed control costs to U.S. growers will increase by
$2 billion annually," Burnside said.

For the past two years he's chaired the National Agricultural
Pesticide Impact Assessment Program's study of the benefits of
phenoxy herbicides such as 2,4-D.  Study results will be used by
EPA when they determine whether phenoxy herbicides should be re-
registered.

An increase in public funding for weed science is needed.
Burnside said, since developing non-chemical weed control methods
won't attract private funding.

(From:  Minnesota Extension Service)