Page 34 - 2019 Ag Mag

34 Integrated Pest Management
KMAland 2019

Managing Pest

Resistance

in Iowa

weeds were not resistant to any- to rely more and more on the use
Larry Buss, thing as we largely fought them of herbicides. By the 1990s, I re-
Harrison County, with “steel” in the form of tillage call seeing weeds, especially wa-
Iowa farmer prior to planting and cultivation terhemp, becoming increasingly
A
during the crop growing season. resistant to some herbicides and
All crop farmers, including my- If any weeds survived those cam- difficult to control. Many farmers
self, have battled pests through- paigns, we came after them by at that time welcomed the intro-
out our farming careers. Pests in hand with a hoe, machete, you duction of a tremendous new tool,
Iowa cropping agriculture basi- name it. Weed resistance then was RoundUp Ready soybeans.
cally come in three forms: weeds, non-existent because weeds had a Farmers needed Roundup to
insects and plant disease. Of these tough time becoming resistant to combat weeds in soybeans, but we
three, weeds have historically “steel.” did not need that technology in
been the pest of greatest concern, corn. Herbicides available for use
year after year. This is confirmed Herbicides and modern in corn, combined with the natu-
as I think back to when I was a boy day weed management ral, rapid growth of the crop, en-
in the 1950s on my parent’s farm, In the 1980s, as agriculture be- abled us to have great weed con-
south of Onawa, Iowa. Weeds gan reducing tillage to lower pro- trol in cornfields. However, with
were the primary pest that we duction costs and combat soil ero- the advancement of the technol-
battled each year. During that era, sion, the fight against weeds began ogy at that time to use Roundup in