A light-hearted look at the Palmer amaranth invasion
by Bob Hartzler

Oct. 19, 2013 -  I can't remember any weed creating such interest as Palmer amaranth in my years as a weed scientist. It is encouraging to see the ag community realize that we won't always have a simple solution for new weed problems, and thus we need to consider other approaches to weed management. One such tactic is to reduce the likelihood of a new weed species getting estabished in areas where it is not present. It is well documented that prevention is the most cost effective way of dealing with invasive weeds, and we are at a time when we can prevent Palmer amaranth from spreading across Iowa.

Palmer amaranth was first found in Iowa in Harrison county in August, 2013. Palmer amaranth appears to have been at this location for several years, and the seedbank probably is extensive enough that it will be difficult, but not impossible, to eradicate. During the period of eradication, steps need to be taken to contain the infestation and reduce the risk of it spreading to new fields.

We have a great example of a community effort to prevent the spread of Palmer amaranth from this infestation. Rich Pope, Harrison County Extension, recently assisted a group of youth and parents from a local church in pulling female Palmer amaranth plants from soybean fields adjacent to the waste fields where it is believed the Palmer amaranth was first introduced. The intent was to prevent the weeds from being harvested by the combine since these machines are extremely efficient disseminators of weed seed.

The farmer with Palmer amaranth in Muscatine county is taking similar steps to prevent the spread of the new weed to other fields. He walked areas of the soybean field with scattered Palmer amaranth and mowed down areas where the Palmer was too thick to pull. Steps like this can greatly reduce, or perhaps prevent, how quickly Palmer amaranth moves across Iowa, and should be strongly encouraged.

After hearing about the church group's involvement in Harrison County , a Bob Dylan song, With God on Our Side*, started bouncing around my head. Following a full day of being unable rid my brain of this song, I decided to see if I could adapt the song to the current situation. My adaptation of the Dylan song follows - I should add that I am not as pessimistic about the impact of Palmer amaranth as my lyrics imply. With improved management we should be able remain on top of Palmer amaranth, waterhemp, and the other weeds we struggle with each year.

Oh my name it is nothin’
My age it means less
The country I come from
Is called the Midwest
We grow corn and soybeans
Control weeds with great pride
And the land that we live in
Has god on its side

When waterhemp appeared
We fought it so well
With Pursuit, then Roundup
All of the waterhemp died
No need for diversity
With god on our side

But then Palmer arrived
And ruined our yields
With new biotech crops
The Palmer would not be denied
We now have to cultivate
With god on our side

So now as I’m leavin’
I’m weary as Hell
The confusion I’m feelin’
Ain’t no tongue can tell
The weeds fill my fields
And we’ve failed the test
If God’s on our side
He’ll stop the next pest 

It is quite clear that I shouldn't give up my day job for songwriting, and only put it on the web site due to encouragement of an unnamed colleague.

*With God on our side. Bob Dylan. Copyright © 1963 by Warner Bros. Inc.; renewed 1991 by Special Rider Music

Prepared by Bob Hartzler, extension weed management specialist, Department of Agronomy, Iowa State University

For more information contact:
Bob Hartzler
1126C Agronomy Hall
Ames, Iowa 50011-1010
Voice: (515) 294-1164
hartzler@iastate.edu
http://www.weeds.iastate.edu

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