Is Palmer Paranoia a Threat to Conservation?

As a wildlife biologist, I admittedly have a less mainstream attitude towards weeds. For me, keeping those less obtrusive but often disgraced varieties of flowering and seed-producing plants on field edges and in barn lots is a good deal for the birds and the butterflies. But, as a wildlife biologist and a conservationist, I know that anything that affects efficiency in crop production affects conservation. So when I heard about the weed called Palmer Amaranth being found across Iowa last summer, I read the headline articles, watched the top stories, followed the unanimous senate vote, and learned how to identify the new pigweed to see where I could help.

Palmer, as it’s called, is a major challenge in cropping systems in the southern U.S. and until 2016 had only been found in five Iowa counties. Then, during the 2016 growing season, that list grew to at least 48  and experts predict that number could be higher.

The culprit? Seed mixes shipped to Iowa from southern dealers to meet burgeoning demand for high-diversity native plantings contracted under the Conservation Reserve Program (CRP). The CRP fields where Palmer was rearing its ugly, thousands-of-seed-bearing head were the same fields lauded by conservationists as the best practice ever conceived under the CRP for addressing the plight of economically and ecologically important insects and many declining wildlife populations.

And, just as Palmer had entered the lexicon seemingly overnight, something else became apparent: “conservation plantings” had become synonymous with “Palmer.”

In the last year, I’ve seen this phenomena play out everywhere from professional meetings to farmsteads. I’ve heard stories from across the state about inquiries on CRP contract termination. I’ve talked with landowners that have dismissed high-diversity plantings out of fear for being the source of a new Palmer infestation. I’ve read gloom-and-doom articles implicating CRP in fueling the spread of Palmer on pages of periodicals from across the Midwest.

Vigilance and education are unequivocally important. My concern though is not with the messaging in educational efforts on this emerging threat, but rather the implicit deduction often drawn. That is, if Palmer is the effect and conservation plantings the cause, won’t less of the latter preclude more of the former?

I don’t have any data to support the veracity my concerns. Only my own experiences and anecdotes, which of course is shaky ground as a scientist. Dr. Bob Hartzler, the respected authority and defacto leader of the important response to the Palmer outbreak in 2016, recently told Iowa Learning Farms in his Conservation Chat podcast interview that he didn’t think concerns over Palmer were driving people away from conservation. I hope he’s right.

Professional educators and everyone in the agriculture and conservation community need to continue to address this emerging threat. But, we need to do so while retaining and building on progress for conservation of pollinators, soil, water, and wildlife that are fundamental to our quality of life and the sustainability of rural landscapes in Iowa. We need to be careful to not lose sight of the original goal of the high-diversity conservation plantings. We need to push a uniform message that less conservation isn’t the solution but rather that more vigilance is. Palmer is a huge deal. But I hope we don’t forget, conservation is a huge deal, too.

Adam Janke

Thank you to Adam Janke, Bob Hartzler, and Meaghan Anderson for their willingness to share photographs for this article!

Dr. Bob Hartzler Talks Weeds on Conservation Chat Podcast

Bob_labelIn the latest episode of the Conservation Chat podcast, host Jacqueline Comito sat down with Dr. Bob Hartzler, Professor of Agronomy and Extension Weed Specialist at Iowa State University. Dr. Hartzler has spent decades studying weeds and helping Iowa farmers manage weeds. Most recently, Dr. Hartzler has been involved in the response to Palmer amaranth and its spread into 49 of Iowa’s 99 counties. The Palmer amaranth weed has been particularly difficult for farmers to control, as it has a similar appearance to waterhemp, a common weed in Iowa. Palmer amaranth, however, grows much more quickly than waterhemp, making early Bob_am_label2identification important (before the plant produces seed).

“We’ve gotten complacent with weeds, because, until recently it was so easy to control them with glyphosate and the other products. A lot of people don’t pay as close attention to the weeds as we would have 20, 30 years ago. If we want to stop Palmer amaranth, we need to pay attention to details again.”

The spread of Palmer amaranth is a reminder that we must implement more diverse weed management programs rather than relying exclusively on the power of herbicides. Dr. Hartzler speculated about whether the need for more comprehensive weed management plans might ultimately change our cropping systems.

“Whether we can continue the current production system relying solely on herbicides, I think that’s up in the air. We’re not discovering new herbicides like we were 20 years ago, so we’re running out of options. I think it is going to force us into a more diverse management program . . . It’s hard to believe that something as simple as a weed might force us out of the current production system that we have.”

Palmer vs waterhemp_labelIn the current management system, “We’re relying almost entirely on the herbicides, so that make it very easy for the weeds to adapt,” Hartzler commented. “A more diverse crop rotation would be the best route to go. . . [the weed] has to find a way to survive in a crop that it’s not adapted to.” Tillage is another tactic that farmers have historically turned to for weed management; however, there are many benefits to no-tillage or minimum disturbance of the soil.

larvae3_labelIt’s clear that Dr. Hartzler has a deep passion for weeds, and for helping Iowa farmers find tools to eradicate weeds now and into the future. Tune in to this month’s chat and learn about Palmer amaranth and so much more – cover crops and weed suppression, monarch butterflies and milkweed habitat, and even herbicide carryover related to grazing.

If you’re on the go, take the Conservation Chat podcast with you – find it on iTunes or search for “Conservation Chat” on the podcast app of your choice!

Julie Whitson