Field Crops Webinar Series - Evaluating Insecticide Seed Treatments

March 21, 2016

MSU Extension Field Crops Webinar Series 2016
Session 5, 3/21/16
Title: Evaluating Insecticide Seed Treatments
Presenter: Dr. Chris DiFonzo

Video Transcript

>> Speaker 1: Good evening and welcome to the MSU Extension field crops webinar series. My name is James DeDecker. I'll be your host this evening. Tonight's presentation is evaluating insecticide seed treatments with Dr. Chris DiFonzo. So, I will go ahead and turn it over to you, Chris. >> Speaker 2: So I think the title of this talked about the efficacy of neonicotinoid seed treatments, but it's actually broader than that; it's kind- what I'm gonna talk about is what's going on in the newspaper, in the scientific community, in government agencies; considering neonicotinoids. And when I'm talking about seed treatments I'm only talking about the insecticide portion of that seed treatment. I'm not making any judgments about your need for fungicides or nematicide seed treatments, I'm only talking about the insecticide portion of that when I'm doing this, this talk. So this was really started're probably seeing a lot of things in the newspaper about honeybees and seed- seed treatments. Over in Ontario now, the use of seed treatments has been severely restricted, especially for next year, for 2017 planting season. A farmer can have no more than twenty percent of their acreage with a seed treatment. So, what went on here and how do seed treatments fit into Michigan? So, as an entomologist, it has been stunning to see how neonicotinoids have taken over the insecticide market. When I was in graduate school, we used organophosphates and carbamates, and pyrethroids were just becoming popular. And in the last few years, neonicotinoids have really taken over as the OPs and carbamates have fallen out of favor. So this slide just shows you all the different ways that we use neonicotinoids; not just on crops...and on fruit and vegetable and field crops, cotton, but also in nursery and ornamental market; around the home, not just in turf, but for all your home pest control needs; termites and such. We use it for tree injection, for things like Emerald Ash Borer in Michigan, and even on pets for control of fleas and ticks and such. So, neonicotinoids are now used in one hundred and twenty countries. They're a quarter of the global insecticide market, and they account for a lot of the sales, so if you go to Home Depot and look at the insecticide labels like I do, you cannot escape these. They've really taken over. So the next few graphs I'm going to show are from a paper by Douglas and John Tooker, who is my colleague at Penn State. And it's a really great paper if's a good review paper; if you want to copy of it, you can email me and I'll send you a P.D.F. or somehow get it to you. But in that paper they, they took data on sales of neonicotinoids to try to figure out what the use was by year and in different crops, and this is been very hard to find through government data because it kind of doesn't exist, so they put a lot of data together to, to make these, these graphs. And when we're talking about neonicotinoids, we're really only talking about three of them that account for the market. Imidacloprid; that came out first in the early nineties. That's the red bar on the graph. Clothianidin and thiamethoxam- those now account for the majority of neonicotinoid use in the United States, and this graph shows the tremendous increase, especially since 2003 or so, in the use of these products by pounds in the United States. This shows you where the use is occurring. And yes, we can use neonicotinoids on turf and on cotton and on animals like, for fleas and such and around the home. But the majority of use, the red here, is crop use. Most of the neonicotinoid is not homeowners or nursery folks, it's used on crops. And which crops? Well, pretty much, corn and soybean are the biggest two. The next one up would be cotton. But corn and soybean account for the majority of neonicotinoid use by pounds in the United States. And that is via neonicotinoid seed treatment, or N.S.T., as I'm going to call it throughout the rest of this, of this talk. These maps are from the US Geological Survey. And they show the, essentially, the pounds used per square mile of neonicotinoids. And you can see that because we're talking about crop use and corn and soybean use for the, for the most part, the most intensive use is in the Corn Belt. Across Minnesota, Iowa, the 'I' states, up into Michigan into Ohio. Down the Mississippi River, where you get some cotton use. And then you see some areas of fruit and vegetable use in, like, Florida, along the East Coast, California, and Washington. So clothianidin is the active ingredient that's in Poncho. So when I'm talking about that, think about Poncho seed treatment that we have a lot on corn. Thiamethoxam is the active ingredient that is in Cruiser or Cruiser Maxx. So, that, we see a lot of use on soybean. So if you added up the- I'll go back- if you looked at this, at this use pattern, and you added up the pounds that are used and then looked at the area that they're used on, the actual acreage, it's about forty percent, maybe fifty percent of soybean acres are seed-treated throughout the US. Fifty percent of cotton, and eighty-plus acres- probably close to ninety- of corn. If you added up that acreage and put that onto a map, it would essentially equal the size of California being treated now every year with neonicotinoid seed treatments just in these three crops. So again, as an entomologist, this is a stunning amount of insecticide use that is coming pretty rapidly from these...from this one set or one group of insecticides. So, essentially, we're treating the area of California every year. So why were neonicotinoids adopted so fast and so quickly? Well first, their toxicity profile is better than OPs and carbamates; those of us who are old enough, like me, to remember what it was like to use an organophosphate- OPs and carbamates are extremely toxic in the insect nervous system and in the human nervous system. So, they're acetylcholinesterase disrupters. They can be quite dangerous, and many of us have probably been poisoned or felt queasy after using something in, in the past that was an OP or carbamate. So neonicotinoid seed treatments or neonicotinoids as a group, they work better in the insect nervous system than they do in the human nervous system; they have a better affinity or better binding. So they're actually- I don't want to use the word 'safe', but they are safer than an OP or a carbamate. So neonicotinoids hit the market at a lucky timing. In the middle of the 1990s. This is when the food quality protection act or FQPA had just been passed, and that was asking companies to replace OPs and carbamates with something safer. And what was there? Pyrethroids and neonicotinoids. The other lucky thing for neonicotinoids was that BT corn, the first commercialized BT corn, also came out in 1996. And, you know, that corn was more expensive; you had a...a certain amount per bag extra that, that was paid, and companies did not want complaints if the corn was eaten by grubs or some other insect. So neonicotinoid seed treatments were put on BT corn as just a matter of course. All BT corn is seed treated, and part of that is to protect that extra investment, reduce the workload of folks going to your fields and having to investigate claims, and that package the...acreage of neonicotinoids greatly. The reason that neonicotinoids could be used on BT corn as a seed treatment was that they are systemic. That's unusual; there's not...pyrethroids, for instance, are not systemic; you can't put the pyrethroid on a plant and it, and then it moves into the plant. So this is a pretty incredible property of neonicotinoids that they are systemic. And once they move up into the plant, say corn or soy bean, they're protecting for about three to four weeks until the seed treatment is gone and the plant breaks it down, and then there's new plant parts growing. And this systemic movement and use as a seed treatment was also highly favorable because now you had less exposure to workers or to people that had to mix and load insecticide. So there's less broad spectrum impact of a neonicotinoid compared to spraying. So all of these things- the lucky timing, the systemic properties, the way that you could put it on seed- made it highly favorable, and it replaced a lot of the OPs and carbamates that, that we were using. So this is a kind of a busy slide, but by 2013, we were treating most of our field crops' acres with seed treatments. And, the EPA, as problems began to occur and people began to talk about this, a section of EPA that are economists sat down and did a, an ec- an economic assessment of neonicotinoids on soybean; not corn, we're talking just about soybean. And they called in data from a lot of studies that weren't published and called in data from the public sector, and did an economic analysis, and this is what they found; the underlined parts are the most important. And they came to the conclusion that soybean growers derive limited to no benefit from neonicotinoid seed treatments in most cases; that the use did not protect soybean yield better than essentially doing nothing in many cases. Much of the observed use was preventative- in other words, insurance use not providing actual pest control. That, if for key foliar pests; I'm thinking soybean aphid here, there's efficacious or good alternatives that are foliar sprays. And then ultimately, seed treatments have a short early-season period of bioactivity. So this report came out in 2014, in October 2014; you can go to an EPA website and read it. So, what's behind this report; what's the truth in it. So the amount of 'benefit' that you get from any insecticide or using it, including a seed treatment, on your acres, year after year, is a function of a couple things, so I just made this up out of my head. The first is efficacy. So, in the case of the seed treatment, it had better work; it had better kill something, or control something and protect your seed and the stand. The next thing you'd be interested in would be the timing. Is the insect that you're interested in controlling- is it exposed to a lethal dose of seed treatment before the seed treatment breaks down? I already said that the seed treatment moves up into the plant. You have a three to four week window, and then it begins to break down. And the final thing you'd be interested in would be the probability that the insect you want to kill- is that important? Is it there every year? Is it in all of your fields? Is it something where you are going to get a benefit if you control it year after year? So if we work through these things, first of all, what's the efficacy of seed treatments; what do they actually control? Well, we have a number of pests here, and I've got corn and soybean up on the screen. And in corn you have things like black cutworm early in the season and beetles, flea beetles; on soybean you have aphids and bean leaf beetles that attack early. And then for both crops, under the soil or on the soil surface, you have seed corn maggot. That's this big guy here if I can see my, my pointer. Grubs, which we have a lot of. Wireworms. And then slugs, which are an increasing problem. So if we look at seed treatments, these things- I'll do it again- these things immediately drop out. So black cutworm and flea beetles are not well controlled by seed treatments up on the plant. And, if we go back again, we had slugs. Slugs are not insects. They are not controlled by neonicotinoids. And finally, grubs. Grubs, we have a tough time with neonicotinoids. The original labels had words like 'suppression for grubs'. The grubs are not controlled, that the populations are reduced but not eliminated and controlled one hundred percent, so there, we would use the word 'suppression', which I think of as, 'doesn't work very good'; that's what 'suppression' means to me. And we have a lot of grubs in Michigan. And I would rate that most of these neonicotinoids help when populations are not very heavy; kill a portion of population. But if you really have grub pressure, they don't do so much. So what's left? Neonicotinoids work very well on seed corn maggot, typically. They work pretty good on wireworm. And those are under the soil. So, as far as efficacy, there's efficacy on a certain group of insects. The next question is timing. Now, the insects under the ground, like grubs and wireworm, are present at planting. So the timing matches up with when the lethal dose of this seed treatment should be present. Seed corn maggot attacks the crop just after it's been planted, or the female flies are coming in and they're attracted to decaying material, so they would also be there at planting. So for those three pests, that makes some sense. Now as far as on soybean, bean leaf beetles overwinter as adults. They are present right as the crop is coming out of the ground, and beetles are typically hungry. Now to be fair, I have never seen a bean leaf beetle population in a field over threshold, but they would be there to be killed should they be there. The one pest on the slide where this doesn't fit, where timing doesn't fit, is soybean aphid. So if we look at the relationship between the dose of neonicotinoid seed treatment and the typical soybean aphid populations in a field, if you look at the early vegetative stage, that's when the neonicotinoid concentration up in the plant is the highest. And then it dec- it...declines over three to four weeks until it is quite low. It could be detected with chemical means in the plant, but it's not a lethal concentration. That decline is happening just as we're getting into flowering stage, and late flowering into early reproductive stage is when soybean aphid really takes off; that's when the plant becomes a banquet for soybean aphids. So you've got this time period where you have a non-lethal dose of seed treatment sticking around in the plant but not really killing aphids. You then have aphid colonizers arriving right at that time and colonizing the field and taking off. And the third thing that you don't typically see, because you're not out in the field crawling around like me, is you're not seeing the effect of that neonicotinoid on that seed early in the year on natural enemies. So if I'm a natural enemy- some kind of predator; a ladybug; whatever- I am not going to be interested in your field if you've used a neonicotinoid and that neonicotinoid is present in the first few weeks. There's nothing there for me to eat. There's no aphids. There's no thrips. I have no reason to colonize your field and be looking for these early aphid colonizers. So we know, from a lot of different studies, that when you have these neonicotinoid treated fields, you also have fewer natural enemies there because there's just no prey for them to eat. So you have a triple whammy. Non-lethal dose of insecticide, aphids coming in, nothing to eat them. So this is why the EPA stated that seed treatments had a very short early season period of bioactivity. This declining concentration here; three to four weeks is all that you get, and then you're in a non-lethal dose. So here's some actual data from Michigan on soybean aphid, and this is 2005. Those of you who remember 2005 up here, this is Saginaw County. 2005 was the aphid year from hell. It was the biggest aphid infestation or outbreak we've ever had, and we had the biggest outbreak in the entire country. So this is my data. I'm moving some things aside here. This is my site in Saginaw County, and on the axis going up you see that's the number- the average number of soybean aphids per plant. And along the bottom we've got time. So, the untreated plots are in, like, a brownish color. I also had a Cruiser seed treatment. And then I had a set of plots- and these are not small plots, I should say; these are over-acre size plots. I had a set of plots that were sprayed with Warrior at threshold, so we were scouting every week. So the first thing that you see is right at R1, when the plants are just starting to, to flower, that was fifty days after planting, and all plots are infested at this time with aphids, including plots that had been Cruiser seed-treated. By July thirteenth, all plots crossed the 250 threshold. It didn't matter if they had Cruiser on them...we spent money on Cruiser at the beginning of the season or not. That made no difference. The timing was exactly the, the same whether I had Cruiser on it or not, because the Cruiser had already run out. So if you look at the aphid numbers, the plot in green, this was a plot that was sprayed on July thirteenth when we were at threshold, and it remained low with aphids through the rest of the season. It had some aphids kind of hanging on there, but it wasn't re- recolonized, and that was the end of the story for that plot. The plots that had no treatment got up to, in the early August, sixteen thousand aphids per plant before they ruined their plants, and then the populations dramatically dropped. And then, the plot with- plots with Cruiser on them were delayed a bit compared to untreated, but they still got up to twelve thousand aphids per plant. Once that Cruiser was in a non-lethal dose, the aphids began to multiply and they were able to reach twelve thou- twelve thousand or so aphids per, per plant. If you look at the yields compared to the untreated, yes, Cruiser, you had thirteen bushels back from that treatment. But just by using Warrior and spraying at threshold in a very judicious way, you made almost twenty bushels back. So the right thing to do in 2005 in this county was to spray Warrior at threshold. [SOUND] Whoa...there we go. So, here's this same exact plot...the same exact study in the same exact location in 2006, so 2006, the next year after the outbreak, there were very few aphids at this location; in fact, I didn't even reach one aphid per plant. And you can see my, my peak throughout the season was less than half of an aphid per plant in July. So the untreated plots ha- the yield was fifty seven bushels. My sprayed-at-threshold plots, fifty six, and Cruiser, fifty five. The difference here is that this sprayed-at-threshold plots that had fifty six bushels an acre were never sprayed, because I never reach threshold. So that was essentially like an untreated treatment. The Cruiser, however- there were no significant differences in these yields. But I had to pay for Cruiser; if I'd been a grower, I would have had to pay for that Cruiser seed treatment [NOISE], and I wouldn't make that, that money back. So just because Cruiser can work on aphids if aphids are present very early in the season, that tells you nothing about the probability of infestation, which is very important. So when you look at insecticide efficacy trials that are shown to you in ads or brochures...on T.V. advertisements, or in magazines, in marketing materials; those studies were not done in random fields. When I'm called by a company to do a study, I am biasing that study to try to find a pest so that they can test their insecticide against a pest. I find a natural infestation, I create an infestation, or I plant in ten locations- one location is infested and I use that location to gather the data. I'm not- the company is showing you trials where there was a significant difference because there was a pest infestation. They're not accounting for trials that didn't show a difference, or that didn't have insects. So that's a very important thing to realize. So here is the aphid infestation over time from 2001, the first year that we had soybean aphids, all the way up to 2014. This is the average number of aphids per plant. And in the first five or six years, we had this every other year cycle. High in 2001, high in 2003, super high in 2005, the aphid year from hell. But since 2005, after that initial up-and-down kind of cycle, aphid numbers have been actually pretty low in Michigan since 2006. We had a little mini outbreak in 2013 in a few places; some people sprayed, some people didn't. What's the difference? Well, now, all of our predators out there- ladybugs, parasitic wasps- they've all learned to eat aphids. They've learned to use aphids as food. And it took them awhile to, to figure that out, but once they did, they've been able to keep our populations in check almost every year. So back in 2001 or '03 or '05, you might have thought, well, using Cruiser was a no-brainer; I'll always have aphids and I'll get some kind of effect. But since then, if you look from 2006 on, we've had aphid numbers that have been quite low. And this is very different compared to folks in Iowa or Minnesota. They have continuous outbreaks every single year. And the difference seems to be that they spray at the drop of a hat; when they see aphids, they, they spray. Unlike, I think, farmers in Michigan that are trying to do a better job and wait to spray if they have a problem. We actually have predation and parasitism that they never, ever see. So if you were going to look at aphids- aphid infestation, the probability of a troublesome infestation has been greatly reduced. So, if you look at other insects- other early season insect problems. I don't have a lot of good data in Michigan, specifically, on some of these other insects, but some of my colleagues do. So these are a couple studies that were done by my colleague John Tooker, who did the initial maps of the...or the graphs of the different types of neonicotinoids in, in the market. So he has been funded by his soybean board to look at early season scouting and early season insects in Pennsylvania. It's not exactly Michigan, but Pennsylvania shares a lot of the same crops that we do; a lot of the same landscape and field sizes. So, I think it could fit for Michigan. So they did two different studies. One where they went to twenty four fields and they had people scouting and trapping them for early season insects across one year. But twenty four different places. The other study was to go to twenty fields and scout those, in, like, 2012, and they went back to the same twenty fields for four years in a row, so essentially eighty site years, looking for...insects over threshold. And this is what they found. In the early season scouting, twenty four fields, they found seven insects. Not seven fields infested, seven insects. Two grubs, four bean leaf beetles, and one wireworm. So it shows you that in a lot of these fields, there's not a lot of early season insect pressure. Slugs seem to be the thing that they get a lot of in Pennsylvania, but not insects. In the sentinel plot program, where there were eighty- essentially eighty field years, throughout those four years there was only one field that had a treatable population. And that was a soybean aphid infestation. And it was sprayed and gotten rid of. So that was one out of eighty times did they find an insect population that was over threshold. I also asked some of my colleagues around the Great Lakes, you know, 'What do you see in your fields? Do you typically get phone calls?' And we were trying to be very generous, like, how many acres at our- in our state would be at risk for an early season infestation of a soil pest? The average was fifteen percent. For Michigan, you know, I would say it's five to ten percent. Some years are a little worse than others, but I rarely get calls about early season insect problems. Unless, maybe, grubs here and there. And what pests are the most common? Well, for me it was slu- for me, it was white grubs. For some other folks, it was slugs; as we go to more reduced tillage, we're seeing more, more slug issues. Number two is black cutworm; number three was wireworm. So if you look at these four pests, grubs are suppressed by seed treatments. Wireworm I would say is controlled. But black cutworm and slugs are not well controlled, or not controlled at all in the case of slugs. So, two of our top four don't even- aren't even controlled by, by seed treatments in the first place. This is why EPA said in their economic benefit document that the observed use of neonicotinoids in their view was preventative; it wasn't really providing any actual pest control for many people. So that, there just wasn't- there's just not much out there to kill, especially in the Great Lakes region. When that seed treatment is out there, it's being put out there as insurance, not with a target in mind. So if we look at this metric that I had earlier, as far as effi- efficacy, neonicotinoids are effective against some pests, a limited number, particularly seed corn maggot, wireworms, and then bean leaf beetle if you were to have them. Most insects, however, infest fields in Michigan and surrounding states well after crop emergence, when the dose of the seed treatment is dropping and becoming non-lethal. And, for most of us, the probability of a pest over threshold is pretty rare. So that's why EPA, again, concluded- and most of the public sector entomologists like me agree- that growers derive limited to no benefit from seed treatments in most instances. And I think that really, what EPA was talking about was soybean, not necessarily corn. Really focusing on soybean. So when, so what are- what would the situations be if we, if we go back, that in most instances, you don't derive a benefit. What would be the instances that you would derive a benefit? So here are some instances that when seed treatments came out, public sector entomologists like me were kind of excited because these were the instances, or these were the growers, that we thought seed treatments could help the most. And the first would be when you're transitioning a field or an area out of pasture, or CRP ground, or some kind of similar habitat. And that's because wireworms and grubs, some of them live long lives under the soil. Two to three to four years; wireworms, even longer. So where you have that grassy stand, that has a much greater chance of having wireworms and grubs than would an annual field that is farmed every year. So when you're transitioning out of pasture, it would be a no-brainer to use a neonicotinoid. Another situation is where you're using a green cover crop that is, that has made it through the winter into spring. Or you're a dairy, have some livestock, and you're incorporating fresh manure into your field. Or you have a very heavy weed mat early in the season, and you're going to work that in. And that's because the decaying green material or manure, very fresh, is very attractive to seed corn maggot adults. And that's where the adult fly will lay her eggs. Now, once that manure has dried down- once the cover crop is dead and crusty because you RoundUpped it- they're not interested in that. They're interested in dying, dead, stinky, breaking down stuff. So, if you have some fresh manure put on, or you have a cover crop that is being worked in and you're going to plant pretty quickly after that, say a week, a week or two, using a seed treatment would be probably a good idea to avoid the seed corn maggot. Although, to be fair, I have never seen seed corn maggot. I have heard and seen pictures. I have never personally seen a field that was inundated by seed corn maggots, even if it had weeds and some other issues. Grubs can also use some of these green cover crops as a bridge, so sometimes you do get grub populations. If you grow specialty soybeans, food-grade soybeans, seed soybeans; not so typical in Michigan, but bean leaf beetle can spread a couple different viruses and...they would be killed by a seed treatment early in the season. I have, again, have never seen a field over threshold for bean leaf beetle ever in my life early in the season in Michigan. I've heard about them in Minnesota and Iowa; I've never seen this in Michigan. And the final thing would be double-cropped beans; these double-cropped beans that go in late, like after wheat. They can be kind of a tasty morsel to aphids because they're, they're young when the rest of the soybeans around them are getting old and some of the aphids are coming off onto these young beans. But...I would always prefer to manage soybean aphid with a foliar spray that I can time, and not use a seed treatment. So in this case, I know- I understand why, if you're going to double-crop beans in southern Michigan, that you would do this and use a seed treatment. I would just prefer to- to spray the little buggers. So I do think these first two, the transitioning out of pasture, and this green cover crop weeds and manure; the top two situations really are kind of a no-brainer for seed treatments. So we've talked about the efficacy, the timing, the probability. But we haven't really mentioned the costs, and by cost, I don't mean the cost of the seed treatment, because it does cost you something if you're going to put on the full seed treatment. I'm talking more about some of the costs we don't talk about a lot, which are resistance and environmental impacts and things like that. And these are the things that have...that you've seen in the newspaper recently. These are the impacts that we're hearing about more on the news. So the first thing that we discovered about neonicotinoids is that there can be off-target movement at planting. So we wouldn't have thought that. This is a seed treatment. It's on the seed. The seed's going into the ground. What possible thing can that seed treatment do in the environment other than it's sitting there in the ground? Well, we had to learn the hard way that with some planters, especially like a vacuum planter that's venting or exhausting up into the atmosphere, that as that seed, that treated seed, moves through the planter, it is abrading. Seed treatments are rubbing- the seed treatment is co- the seed coating is sort of rubbing off; it's powdering; it's becoming like a dust. And then that dust can vent out of the planter. That contaminated dust moves on the wind to the edges of the field. And it lands on, say, dandelions or other early season flowering weeds that are worked by honey bees. So, this original work was- or this original problem was identified first by folks at Purdue in Indiana. There were bee kills in Indiana real early in the season when there was nothing going on, nothing was being sprayed; the only thing that was being done was planting of corn. And that was traced back to high neonicotinoid content. The bees were dying from neonicotinoids on the edge of their hives. The pollen they were collecting had neonicotinoids. The nectar they were collecting had neonicotinoids. So what we know now is when you plant, and you're planting with a neonicotinoid, that stuff is coming out the tractor exhaust, it can move to the edges of the field, and again, it's moving either to low-growing weeds that are flowering that are very attractive to bees; the only thing for them to feed on, then. And, the edges of the field, these tree lines, are loaded with trees that are blooming. There's trees that are blooming now, actually. So bees early in the season need something. They need, they need some form of nectar and pollen, and they get it from these tree lines and from these low-growing weeds and flowering plants along the edges of fields. My colleagues in Ontario have done a ton of work on this through looking at how neonicotinoids exhaust through the planter, how far they move, where they move, and, and this seems to be a real effect. So this is one thing that we would have never thought of as entomologists. We would never have predicted that this early- that there would be early season impacts on pollinators that's due to planter dust exhausting out of the planter. The other thing that can happen is that once the crop is planted, and the neonicotinoid is moving up into the plant, there's a portion of it that does get taken up by the crop. And it's actually shockingly low, like, two to twenty percent. But some is moving up into that crop. And I already told you that early on in the season, this crop, whether it's corn or soy bean, has a lethal dose of neonicotinoid in it for a period of, of time. And that would kill any, you know, aphids or thrips; tiny, tiny insects that you probably don't see that are alternative prey for beneficial insects to come in and colonize your fields early. Things like ladybugs, minute pirate bugs that you've probably never seen, spiders- things like that that come into your field, set up residence early, and that are there when things like soybean aphid comes in later. If you have a neonicotinoid treated field, it can be kind of a desert; not a dessert, a desert for some of these insects. And they just won't be there. I'm not saying that they're dying from the neonicotinoid, because they're not necessarily- they're not feeding on that plant; there's just nothing for them to eat, so why would they be there. We do know that natural enemy populations- we know this from many treated crops- can be reduced, first of all, by that lack of prey; we've already seen that. Another thing is that there are a few of our natural enemies that will feed not just on other insects but take a little bit of pollen, or even feed a little bit on juices from treated plants, and one of them is this minute pirate bug that's at the top of the slide here. This is a little teeny teeny tiny bug, but very heavily predacious. And they eat a lot, tiny caterpillars, like little European corn borers for instance, or Western bean cutworms, or aphids. They're very heavily predacious. They will actually sap-sample; kind of feed on plants to get a little bit of liquid. And we, we know that minute pirate bug populations are very much reduced on, on treated plants. Another impact that we did not expect would be that you could create toxic prey on, on seed treated plants, and the most common example, or the example that is the most famous, are slugs. Slugs are molluscs; they're snails. They eat through a seed treatment, it does not affect them; they just ingest it in their bodies and essentially use it as food, essentially. But as they're ingesting it, and as you know, slugs are kind of gross, and there's not many things that eat slugs. But some of the things that do are some species of ground beetles or carabid beetles; these are like little tanks that motor across the soil surface, find slugs, and there's a few species that really like to eat them. So when you have a slug problem the thing you want are ground beetles. Well, this is some data from John Tooker at Penn State again; he's done a lot of- he's kind of a slug ex- slug expert. This is throughout the year, May through October. These are fields- these are actually corn fields- where you have seed treated fields; that's in the red. And then, corn without a seed treatment. Or- not a seed treatment; I should say, without a neonicotinoid seed treatment. And that is the blue line. And since slugs are not killed by the neonicotinoid, you'd expect the lines to be exactly the same- that there's no impact of neonicotinoid on slug populations in fields. But you can see that the red line is consistently higher than the blue line. There are more slugs where you have treated seed than where you have seed that does not have a neonicotinoid, and what the heck is going on there? So what- what my colleague did was, he got slugs that had fed on treated corn plants, and he realized the slugs are just fine. But when the ground beetles encounter these slugs, they either die, or they feed on them and kind of have a toxic reaction and kind of hang upside down and twitch a lot. So the slugs themselves are toxic. And on the bottom here you can see, these are...where it is 'not detected' on the top, this is actually taking slugs and grinding them up and testing them to see if they have thiamethoxam in them, one of the neonicotinoids. And in corn that does not have a seed treatment on it, of course that- it's not detected. In corn where the slugs have encountered the neonicotinoid, the slugs have a lot of this neonicotinoids in their bodies. And they are not harmed by it, but their predator, the ground beetles, are harmed. So, in John's area- in Pennsylvania- he has some dairy producers that their biggest pest are slugs. Their biggest problem is slugs. It reduces their stand, they're guys. And so for them, some of these fellows have gone to a seed that does not have a neonicotinoid on it, and this is corn, mind you, in order to produce a crop, because the slugs were a bigger problem than any other pest that they could have out there. So you can see that if we get into a very sluggy kind of situation, neonicotinoids might actually exacerbate the problem by creating toxic slugs and harming their predator. So another impact of neonicotinoids would be impacts on non-targ- non-target organisms after the other plants, not, we're not talking about the corn and the soybean here; we're talking about plants in or around the, the field. So we've already said that neonicotinoid dust can blow out of a planter. Well, soil from a neonicotinoid treated field- we can detect neonicotinoids up to two years after a neonicotinoid has been used in that field, and you haven't used it for two more years. So that means that...that soil can be blowing around, it can land on the edges of fields, in and on other plants, and that neonicotinoid, being systemic, can move into other plants around the field. Weeds; for instance, dandelions, chickweed, and even into things like milkweed. So these are just a few examples. There are dozens and dozens of papers from Europe, from Canada, and from the U.S. looking at lots of other organisms across the landscape and trying to see if there's an effect of neonicotinoids on them. One of the most famous cases of- is of course monarch butterfly; that's on everybody's mind all the time, this is our national insect, kids raise it. We know that monarch larvae, the caterpillars exposed in the lab, to low levels of neonicotinoid- they're smaller, they don't weigh as much, they develop slower. So we know that out in the field, monarchs exposed to neonicotinoids...likely, there's the same effect. Bees are a big issue. Here are some native bees on this side; not honey bees, just- there's hundreds of other bees out there that are native that are pollinating crops and pollinating lots of plants. And there was a study done in the, in the southern part of the U.S. looking at flowers around the edges of fields, and a quarter of all the flowers that were sampled, the nectar in those flowers contained neonicotinoid. So of course when these bees, these native bees are, are working flowers, they're likely being exposed every day to some low-level amount of neonicotinoid. What does that do to them? I don't know if we're exactly sure. But they need to navigate and find flowers and find their way home, and if they're...maybe not dying outright, but maybe getting stupider because they're ingesting this neonicotinoid, we really aren't sure. And even things like- in Europe there's a great study on birds, and that shows that there's, like, not just one species of insectivorous or insect-eating birds, but like, I don't know, fourteen, fifteen, sixteen different species. The population of those birds tracks inversely with the use of neonicotinoids in Europe. So as the neonicotinoid use has gone up in European crops, the bird populations have, have gone down. Now it's a, it's, like, a correlation, but it's kind of interesting because neonicotinoids overall early in the season kind of dampen any insects that are, that are in those, in those fields, and that's what these birds eat. So it could be just reducing prey. Another thing about neonicotinoids; the great thing about them is they're systemic, right, so they move up into plants. But, because they are systemic, and they're water soluble, they also can move around the landscape in water. So neonicotinoids have been found in puddles in fields, along the edges of the fields in ditches, they go out of the tile line; they run into ponds, into streams. And, because they're insecticides, they then cause re- reductions in the insects that live in streams and ponds and ditches. And these are insects that are kind of at the base of the food chain for things that you might like, like fish, if you're a fisherman, and other aquatic organisms. So we know that- from a number of papers- that we're seeing dequ- declines in aquatic invertebrates in water that's contaminated. And they're, and they're gone. There's a couple of big studies that were recent. This one at the top here, this was a study done by the U.S. Geological Survey, so I think it's a pretty good study where they are sampling waters across the United States; in this case, in twenty four states. And they have found neonicotinoids in half the streams tested; that would not be a sup- a surprise; we use so much of it as seed treatments in the soil it would not be a surprise to have some of it running off, and I know James is interested in this and in wanting to do some, some testing himself. Another study that was done, again, by my colleagues over in Ontario- so if you look at this, this is the map of Ontario; here's Lake Erie, I don't know if you can see my, my pointer. They actually worked with their beekeepers and their corn growers to sample water and soil all around corn fields that were near bee yards in Southwestern Ontario, so very close to us, and every sample that they collected of water and soil had some amount of neonicotinoid in it, and they even sampled snowbanks and found neonicotinoids. And that makes sense; if the neonicotinoids are there in the soil, and the soil is blowing...blowing around and you get those dirty snow banks at the end of the season like now, that dirt's probably carrying some of that neonicotinoid and we're able to detect that. So the bottom line is, we're using- so many acres are treated with neonicotinoid, it's no surprise to find it around the environment. And now people are trying to determine, what does that mean. The final thing that we worry about because we're using so much neonicotinoid seed treatment- is this the risk of developing insecticide resistance? And this is a graph accumulating the number of insects or arthropods that are resistant to one of the neonicotinoids from 1994, when Imidacloprid came out, to 2013. And you see a few years of use when nothing was happening, and then we've had a slow stairstep up toward about twenty...nineteen, twenty different species. Most of these are not relevant to field crops; they're in greenhouses...they're insects in nursery. But there's one that caught my eye. And that's Aphis gossypii. This is the cotton and melon aphid, and what it can do in cotton is it can take the neonicotinoid into its body, and then it has enhanced metabolism, so it's breaking it down extra fast so the aphid survives. And you may say, 'Well, so what? I don't care about cotton aphid.' Aphis gossypii is the kissing cousin, the near cousin, of Aphis glycines, which is the soybean aphid, and it would not be a surprise to find some populations of soybean aphid becoming resistant to neonicotinoids. We now have soybean aphids that are resistant- I say we; I mean Iowa and Minnesota- has populations of soybean aphid that seem to be resistant to pyrethroids from overspraying, and we do not need soybean aphids resistant to neonicotinoids. So it's a cautionary tale about overuse. So, is there a benefit to using neonicotinoid seed treatments? Yes. Around the Great Lakes, we have certain situations like coming out of the pasture, C.R.P., or the manure or cover crop kind of situation. These situations are limited, and they're predictable. You know that you're using a cover crop that's going to survive through the winter and it's going to be there in the spring and you're going to have to deal with it. You know you have a field that was an old pasture and you're bringing it back into production. So these are predictable, would know that you need a neonicotinoid seed treatment. But instead, we've taken this technology which is pretty amazing because it's systemic and on a seed, and we're overusing it like we've done with many other technologies for pest control, like DDT and RoundUp now that we have so much resistance, and some of our OPs and carbamates that- that we got resistance to. So this is our current use of neonicotinoid. Remember I said it was- we're essentially treating California; this is the area the size of California, with neonicotinoids, and because we're doing that, we're now seeing large-scale landscape issues, contamination throughout the landscape, and there's problems like this planting- this planter dust issue that we never realized could happen but now see because of this use. If instead we used seed treatments on the acreage where it was really needed- more like this- we would be treating something the size of maybe Massachusetts, or Connecticut. And we probably wouldn't be having these conversations and seeing all this stuff in the newspaper. So what can you do as an individual grower? For corn, options are limited. Biotech GM seed is going to come seed treated. And corn populations are much more...that- it's harder to have plants lost in a cornfield and keep up yields compared to something like soybean. For soybeans, I think that they're good at compensating for lost plants or something that was eaten, so for soybeans I think you could get by in many situations without the neonicotinoid portion of your seed treatment if you can convince somebody to do that or sell you that. And of course we've already ordered seed for 2016 and already have it, but, you know, from- most of the time, soybeans might be treated downstream, and so you're able to perhaps opt out of that neonicotinoid. And if I had soybean aphids, I would manage them with foliar sprays. And we do have some aphid resistant varieties that- or, we have the genetics for aphid resistance. Some of the companies have not put it into their, into their seed yet. So, I think for soybeans it's a lot easier to think about not using a neo- the neonicotinoid portion of your seed treatment. In your overall operation, it was planter dust issue is hard to deal with. Anything we can do to reduce planter dust would be good, but the engineering controls companies have not been that interested in them because the issue was found in Canada, and Canada is a small market, so why should we bother. However, this morning, or just, just recently, but in the- I think it was the Minnesota Star Tribune newspaper- if you look that up, there was a court case in Minnesota where, at planting, a grower legally planted his seed; there was nothing wrong with his planting, but the state of Minnesota has determined that there was some nearby beekeepers who suffered hive kills, and those folks were paid, I believe out of a state...a state budget or a state acount. They got damages. This would be, I think, the first time in the United States that a beekeeper got damages from legal planting operation early in the season. So it's s- seems like this planter dust issue which has been very important in Ontario, we may be hearing more about that in the United States if, this spring, people are alert to bee kills and those are reported. Anything you can do to manage insects without insecticide- using crop rotation, for instance; having good soil health, scouting and following thresholds- anything you can do to keep your insect populations low is good, and anything you can do to reduce soil movement and runoff, because if you're using seed treatments, I guess you should assume that your soil does have some neonicotinoid in it. So much of what I've talked about is in this bulletin. Effectiveness of Neonicotinoid Seed Treatments in Soybean- it goes over, it covers much of what I've talked about. It's on this Purdue website for free; you can download it. It's also on my MSU website, which is I have it up there for free. It's seven, eight pages. And you just [SOUND] print it off as a P.D.F. So this was written by soybean entomologists from twelve universities. S- seventeen of us putting our brains together, and we all agree with what is said in this bulletin. If you can't find it, if you can't get it; you can contact me or one of the other Extension agents in Field Crops, and we can mail you a, an actual hard copy because I have those too. Or if you want a few hard copies for some customers or some other folks, I can try to get those to you. So I believe that that is the end of my talk. >> Speaker 1: Excellent. Thank you, Chris. That's some really important and interesting information. I guess that just about wraps it up for tonight. I will say good evening. Hope you all have a good rest of your night. Thanks again, Chris. Great to... >> Speaker 2: You're welcome; bye-bye. >> Speaker 1: Bye-bye.

You Might Also Be Interested In