Purdue #IPM50

For more information on IPM in the North Central Region visit www.ncipmc.org 

Resources mentioned in the episode:
Pest and Crops Newsletter (https://extension.entm.purdue.edu/pestcrop/) 
Corn root worm (cornrootworm.extension.iastate.edu)

Transcript

Speaker 1 (00:03):
Welcome to a special Pest Central limited series celebrating the 50th anniversary of Integrated Pest Management. This collaborative effort focuses on the history and future of IPM in the North Central region and features university faculty and agency staff interviews from around the region.
This work is supported by the USDA National Institute of Food and Agriculture and the North Central IPM Center. This podcast is edited and produced by Michigan State University Extension. MSU is an affirmative action, equal opportunity employer. Michigan State University Extension programs and materials are open to all

Dr. Clif Sadof (00:58):
Happy 50th anniversary from the Purdue IPM Program. Hi, my name is Cliff Sadof, and I'm a professor and IPM Coordinator in the Department of Entomology at Purdue University, where IPM has been thriving since the 1970s.
When it started, we began with starting pilot IPM programs, scouting schools, and then turning it over to private consultants and it thrived for a long, long period of time. And now our most recent entomologist who's working on IPM in agricultural systems is Dr. Christian Krupke, who is who's with us today.
He's going to talk to us about some of the research that he's been doing on BT corn for the past decade or so. So, Christian, I like to start off by asking you to give me a little bit of background about when and why Bt corn was first produced.

Dr. Christian Krupke (01:56):
Okay. The when was 1996, when the first Bt corn hybrid targeting European corn borer was introduced. When we say Bt corn, we mean any corn that has genetically engineered a toxin that is toxic to a specific insect or group of insects. Test insects that is. So 1996 marked the introduction of that first Bt corn, targeting corn borer and later some other lepidopteran pests, corn earworm, and so on. And 2004 was the next major leap when we introduced Bt corn targeting the corn rootworm.
If we fast forward to present day, 2022, the vast majority of all the corn planted in the US, between 80 and 85% expresses at least one Bt toxin targeting one or more pest insects, and usually it is more than one. Usually it's more than one toxin per plant. So when you think of the corn as you're driving through the countryside in the Midwest, and you see a field of corn, the chances are that is Bt corn out there that you're seeing

Dr. Clif Sadof (03:13):
Well, that sounds great, this widespread adoption. So what are some of the benefits of this for the environment and the agro ecosystem?

Dr. Christian Krupke (03:23):
Well, the initial and most widely heralded benefit was reduction in pesticides, insecticides specifically, and therefore improved environmental health, sustainability, and improved worker health. And that was really what made Bt corn so attractive because you're only targeting the pest insects. Bt hybrids are harmless to things like bees and earthworms and other beneficial organisms. So they really are targeting only the pest insects, and that is unquestionably an advance on how we were accomplishing this before, which was primarily using a series of insecticides through the years, most of which the insects develop resistance to anyway.

Dr. Clif Sadof (04:14):
So with all these upsides, are there any downsides?

Dr. Christian Krupke (04:20):
Well, one of the potential downsides is that it's reduced the need and the ability for growers to have decision points or choices in terms of pest management for insects. So for example, in corn, most of the pest management decisions are made when that producer purchases their seed, because that producer decides whether or not they want Bt toxins, whether they want any of those traits, which ones they want. And then corn is sold routinely with neonicotinoid seed treatments on it, Bt corn is. It has some rate of either clothianidin, or thiamethoxam's most common.
And so what that means is there's a lot less reason for growers and consultants to scout fields, because your key pest certainly are covered by the Bt hybrids and your secondary pests are theoretically covered by neonicotinoid seed treatments. So it's an insurance approach to pest management, which is quite different than the way we used to do it before, where we had more of a threshold-based approach.
So one of the downsizes it's been successful. It's been very convenient, but there's less opportunity for off-ramps and to do things differently. So we see all Bt, all neonicotinoids all the time throughout the Midwest. That's generally the way we've been doing corn pest management for at least the last 15 years or so.

Dr. Clif Sadof (06:05):
So, this is pretty counterintuitive. You start off with something that has great potential and lots of great realized benefits, and somehow or other it seems to be running a little bit counter to the IPM philosophy. So what kind of work have you been doing to counter this trend?

Dr. Christian Krupke (06:28):
Well, in some ways, this is the new IPM philosophy. So the IPM that's in our textbooks, and that was first coined 50 years ago and refined, and we've all read about, may be a little bit different. So rather than being really dogmatic about it, I think the approach is to embrace what's good about this one-stop shopping for corn pest management, but while still emphasizing that there are choices and options out there.
One of the things we've been doing is trying to show growers, and show wide a range of stakeholders, what the benefits may be in their region. So for example, in Indiana where we are, we have very low rootworm populations. In fact, we have a hard time finding anywhere in the state where we can routinely get economic levels of feeding. And so when we do those tests, and we don't show damage even to unprotected corn, we can show producers that for them, the technology fees, the extra fees associated with these stacked corn hybrids that target root worms are really not efficacious, are really not going to provide any pest management benefit, and therefore won't pencil out economically. You won't get a benefit from any pesticide or pest management approach if there's no economic level of pests.
That doesn't mean the other Bt toxins may not be efficacious in that same region. So for corn borer may still be an issue. But what we're trying to stress is the fact that if growers ask for these choices, if they look at what the options are in terms of Bt, yes or no, and if yes, which ones, they can fine tune the approach a little bit, rather than going with the maximum stacked hybrid at the highest rate of seed treatment every year, which is an easy trap to fall into, but has certain long-term repercussions, including resistance to both of those approaches that we want to avoid.

Dr. Clif Sadof (08:45):
So how could a grower get some information on how to make choices and get different types of seed corn or beans?

Dr. Christian Krupke (08:58):
The primary way, we primarily focus on corn rootworm with these efforts. That's the one where it historically has been more recently the heavy hitter in Indiana and much of the Midwest. And there's a working group, a regional working group that's based out of Iowa State that's produced part of it, and many other universities are as well. And that's where we try to put all of our information, use that as a clearinghouse. That's a website that is cornrootworm.extension.IAstate.edu. And that's where you could find information about things like trapping for adult rootworms to determine if the following year you need to consider Bt corn targeting root worms, for example.

Dr. Clif Sadof (09:47):
That's great. That's a nice action item. How about the pest and crops newsletter for Indiana growers? I know we have a pretty wide circulation with that one over there. Is that a reasonable spot to get other information as well?

Dr. Christian Krupke (10:02):
Well, that would be the approach if you're looking for in season information and information about a wide range of pest outbreaks and issues. The Pests and Crop Newsletter is our Indiana version. For those listening in other states, they all have a newsletter as well throughout the Midwest. All of my counterparts produce newsletter articles as it's necessary. So the there's no shortage of information out there, is the bottom line.
The corn and soybean world is pretty well covered by entomologists throughout the region. So anybody that wants up-to-date information should look in their region at their state, check the nearest land grant university, and find out what's out there for you.

Dr. Clif Sadof (10:47):
Yep. That's great. And it's also good about that working group so that those people who really want to get the advanced information that they would need to justify not investing in the prophylactic control with resistance, they could get some confidence with that sort of decision from the tools on that website.

Dr. Christian Krupke (11:09):
That's right.

Dr. Clif Sadof (11:09):
Well, thank you very much for, for giving us an update on the field crops aspects of IPM in honor of the 50th anniversary.

Dr. Christian Krupke (11:21):
Okay. Thank you.

Speaker 1 (11:27):
Thanks for joining us to celebrate the 50th anniversary of Integrated Pest Management. Check the show notes for resources mentioned in this podcast and be sure to subscribe so you don't miss any future episodes.