April 22, 2004: There are some 300 varieties of herbicide-resistant
weeds worldwide, according to weed expert Bill Johnson.
“There are many reasons why herbicide resistance
is a growing concern,” said Johnson, a specialist
with Purdue University Extension. “Among them
the widespread adoption of Roundup Ready soybeans, increased
use of no-till practices and the lack of cheap herbicide
alternatives to glyphosate (aka Roundup).”
Johnson has been researching the trend of super-weeds,
especially glyphosate-resistant horseweed, as they spread
across southeast Indiana, a region specifically plagued
by the plants.
“We’ve found glyphosate-resistant horseweed
in Bartholomew, Clark, Jackson and Washington counties,”
he said. Resistant horseweed also is suspected in the
nearby counties of Jefferson, Jennings, Scott, Shelby,
Decatur and Ripley.
According to Johnson, more pesticides, at least two
different varieties, and more applications, beginning
in April are the best ways to destroy the weeds.