A general knowledge about weed biology and understanding how
herbicides work is important to preserving herbicide technology.
The following questions and answers were developed with help
from these weed scientists: Mark Bernards, University of
Nebraska; Kevin Bradley, University of Missouri; Aaron Hager,
University of Illinois; Robert Hartzler, Iowa State University;
Peter Sikkema, University of Guelph; Christy Sprague, Michigan
State University; Daniel Stephenson, LSU AgCenter; and Bryan
Young, Southern Illinois University. What is a weed? The term
generally refers to any plant growing where it is not wanted or
intentionally sown. A plant is considered a weed when it
interferes and has negative effects on a crop. A weed typically
competes with crops for water, light, space and soil nutrients.
Some weeds serve as hosts for crop disease and insects. Others,
such as black nightshade or wild garlic, can impact crop
quality. How do herbicides kill weeds? Herbicides work by
interfering with essential processes nec