Field Crops Webinar Series - Mitigating Control Failures in Bt Corn
March 19, 2018
MSU Extension Field Crops Webinar Series
Mitigating Control Failures in Bt Corn
Well good evening everyone at seven o'clock on my cock and we're going to get started with tonight's program my name is Jim misled I'm an M. issue extension educator housed in Alger County Michigan and I'm hosting the program tonight in along with me online we have Dr Christopher Johnson all from Michigan State University who will be our speaker tonight if you're interested in gaining one recertification credit for Michigan our recall aside applicator recertification this program will be worth one credit and we'll deal with that at the end of the program so for now I want to wing introduce Dr Di Fonzo She is our field crops entomologist in the argument and Knology and with Michigan State for a good long time I'll let you describe that a Christian Christmas or go to person for all things field crop insect related and with that Chris is yours OK Well yes I have been here a good long time and Friday I got my first young man ringing me up at Grand Traverse pie company for a senior coffee so that was really exciting first time that that's ever happened anyway OK So on the field cups etymologist here at Michigan State and I didn't quite know what to do with this kind of had the title wanted decided to do was kind of walk through BT trades a little bit about their history and then how resistance has happened over time so old people like me and Jim we can remember before the advent of the corn there was a lot of hidden loss by specially corn bore boring insides dogs but also root worms under the ground it was tricky to scout for these past it was hard to go in the field do this and we had either full year or granular insecticides that had to be applied and they often didn't work very well so sixty percent of controlled corn more study seventy percent would have been very good the same with with his corn root where but people just kind of lived with it. Well for many years at least one hundred we've had BT insecticides BT is a bacteria it's out there are living on soil in water on on leaf material it's just out there naturally and for some reason that we do not understand it makes a protein. And it under the microscope can use my little pointer here it looks kind of like a crystal people thought it looked like a crystal so they call that a cry protein and people. Realise that when insects ate these bacteria that that they sometimes died and eventually it was discovered that there was this crystal in protein that actually was the the toxic portion and then people began to grow BT in vats and kind of industrially produced it as an insecticide and it's been used for quite a while as an insecticide. So the team out of action this is for example a caterpillar has been cut in half or used the slide a lot in class an extension just a kind of show how B T would would work so the BT bacterias are ingested by the insect as it feeds and it goes into its digestive tract and it gets to the mid gut which is kind of like your stomach and the PH of the mid gut of an insect is not a CITIC like our gut it's actually more like Ph seven it's more basic and in that when that when that bacteria gets to that ph the crystal in protein is actually what they call activated which simply means that it's kind of cut apart a little bit under that high ph and when it is cut it becomes a not just a protein it becomes a toxin to that insect if it's the right insect so the second the first thing that has to happen is that the that the that the protein is changed and the second thing is it has to bind in the gut if the binding sites are not there it's just excrete it out of the insect but if the binding sites are there like it's a caterpillar type of BT The binding will occur and the gut membrane is disrupted it becomes leaky and the insect gets bacteria that is inside of its body and it kind of like dies a gruesome death so very small larvae are most susceptible to this effect larger larvae sometimes it's like the gut gets damaged but they can survive and kind of crawl away and move on so this is how BT works it has to be eaten and then it has to have the right ph and then the specific binding site That was the leaking of the of the gut. So in one thousand nine hundred six the year I actually started at M.S. you the first commercially available BT corn was created so the idea was that the that. BT insecticides were expensive and they were. Hard to apply if so frequently that to kill enough insects a very light sensitive they break down very quickly so companies thought well why don't we just take the crystal and protein the the gene for that and insert it into corn and make the corn make its own toxin is essentially and that's what nature guard was that was from my kitchen and Seeburg ID It was the first commercially available BT corn and the type of cry protein that was an it was cry one a B. and that was specialized to kill corn bore European corn more was the target here so the idea was you could plant the seed the cordon grows the green parts of the plant produce the toxin the corn bores when they're very tiny eat a little bit of plant material and they're susceptible and you get one hundred percent control to sell BT corn the companies were required to do resistance management This was the first time that that this had been done this was not required for any insecticides but it was required for BT because this was a new technology the T.'s were used an organic agriculture and there was a lot of concern so the companies came up with something called the high dose refuge strategy and I'll explain that in a in a minute the refuge part this was a twenty percent refuge for corn warming a twenty percent non BT area in a field or on a farm to essentially produce susceptible insects and we all remember if you planted BT corn right at the beginning twenty years ago you remember having to plant a separate twenty percent refuge. And this strategy was supposed to. Delay or stop resistance actually that the time frame was it was about a ten year time frame the idea was that we could buy a ten year time frame if we implemented this US strategy and it was always thought that you know eventually you could get resistance to this technology but this was going to delay and stop resistance and this strategy would work if a few things were true. The first thing that had to be true was that the corn itself produced a high dose of the toxin like a whopping dose far greater than you could spray on to the plant so that was the first thing and the high dose would kill the really weak susceptible insects that are were were not resistant at all it would also kill what we call heterozygotes or ones that are partially resistant maybe they have one gene for resistance and one gene that's not so they can they're sort of resistant. But they're sort of susceptible to and if they get up big enough dose they would be killed and the only survivors would be the stupor and sex the tough insects that are. Completely resistant and they would be super rare So that's this the second. Assumption is that there's not many of these superbugs floating around. And the next assumption was that. This says this resistant insect would be able to fly around and find susceptible ladies to meet with could be guys too and this is where the refuge Kamen you are planting a refuge in order. To create these susceptible insects you are essentially giving up a little bit of your corn to create a susceptible population that was not exposed to BT so that this meeting would take place now for court more this made a lot of sense because corn bores will often leave the field and go to the field edges and try to find mates there and so if you had a refuge right nearby or or on or on one edge of of a of a field it was likely that this super resistant one would find some susceptible Zz to mate with and remember he's very rare and so he could be dampened out by these susceptible. And then when these two come together a highly resistant and the highly susceptible their their kids their larvae are going to be partially resistant but remember we've put a high dose of toxin in this corn so these are are all going to get wiped out and and so that is kind of how the high dose refuge is supposed to work. The final assumption is that there is no cross resistance meaning that if I plant a field of say Nature guard or one of the Dekalb kind of kind of BT and I get a survivor and it. Is able to. A larvae into a Hercules field or her killer X. corn for field these larvae are not going to survive that they are not cross resistant if I'm resistant to one bt I'm not resistant to another type of BT and they're going to be dead. So each of the bts is independent. So the high dose refuge strategy for corn bore has been amazing it has exceeded the ten year time frame or now at twenty years of good efficacy and this is lucky data to have this is court more populations in Minnesota they have a Department of Ag folks that go out every year from one thousand nine hundred sixty two to the well this could go up to two thousand and seventeen and they sample for corn bores in corn by cutting the stocks apart and they figure out the average number of corn bores per stock one per stock is a lot that's heavily infested So all these little populations going up and down this is each year and you see that corn Boris habit outbreak and then they kind of crash and then they have an outbreak and they crash and that you have this this outbreak and crash cycle. From the night from the one nine hundred sixty S. the last outbreak was one thousand nine hundred ninety six again what that was the year that I came to M.S. you when there was almost four corn Boris' per stock on average in the fields that they sampled and after that year this is when BT corn was introduced and then this gray shading shows the increase and BT acres so the corn more populations have dropped precipitously and they no longer have outbreaks and that's at the same time as the BT acres have increased so for all intents and purposes corn bore is still out there but it is not it's just not a key pest anymore in in field corn it isn't sweet corn. Orne potato pepper gladiola other other crops but it is not a key passed in corn. So that was the corn bore piece that came out in one thousand nine hundred six in two thousand and three might Monsanto introduced nature guard root worm this was the first commercially available BT corn for root warm and it had Cry three B.B. The Cry three type of toxins are beetle toxins and this is a actually an efficacy trial a regulated trial that I had near the near St John's with the untreated to the left. Which is clearly this was loaded with with corn root worm and then the mani sixty three which was the cry three B.B. on the right and it was really pretty spectacular. And here's just some route pictures this is not treated so that's all eaten up here's a soil insecticide I think it was force and here is the Cry three B.B. and these turn out to be a lot of times pretty much the same although the the soil insecticide often will have more damage all this black these black roots or have all been damaged now when this corn came out it was also required of a refuge and the refuge that the university scientists calculated or some of them asked for was fifty percent because we were seeing a lot are survivors out of this product and it's a lot harder to get the BT toxins to express in the root tissue to be made in the root tissue than it is in the in the above ground plant but because twenty percent was already the refuge for corn bore. National Corn Growers and others really lobbied for a lower refuge for a twenty percent for a twenty percent refuge so that's what the marketing ended up being Chris could I interrupt just for a minute Sure I sailed to encourage people to type any question. Actions that they may have as you call US are your talk in the Q. and A Just click on the Q. and A tab and type your question in there sorry Chris No that's good yeah and I'll try to answer as as we go and Jim will but in because I ramble and I may not see the question so right now this is where we stand as far as the proteins in the U.S. all the ones at the top These are all Caterpillar proteins Here's the original cry when a B. This is the Hercules Hercules talks in Cry one F.. These are the proteins that are in some of the other. Smart stacks some of these and then this is the dip three a toxin which doesn't kill corn bore but has good efficacy against like your worms and Army works and then we have a series of Cry three S. that attack corn root worm not just the original Cry three B.B. one but cry thirty four thirty five is the Hercules toxin. So our transgenic corn acres are now quite high the latest. Figures that I that I that I could get we have very little just bt only corn going out there it's just a couple percentages and most of our corn is a BT plus a herbicide and many times there are multiple types of BT in that crop so we are well low we are we are close to or eighty percent if not more in some cases but eighty one percent nationally I think Michigan's pretty pretty typical. So when you use this much when you get up to eighty percent of the of the acres with this with a certain number of toxins. You would think that we were a group that we might see problems and the first shoe to drop was not corn or anything it was fall Army worm which which we typically don't have a lot of in Michigan and it wasn't in Michigan or the or or the mainland of the US It was in Puerto Rico in two thousand and. Rick so almost more than more than ten years ago so this was really interesting because Puerto Rico is where a lot of the seed production takes place the winter seed nurseries for a lot of the a lot of big companies it's huge and fall army where we occasionally get in our field corn but it's not a typical passed every year so this came out actually Dow was the first to report this and this was the first what we call field evolved resistance to BT corn meaning it wasn't done in a laboratory it was an artificial It happened in in nature but Puerto Rico's weird it's got a tropical climate so it's got pests all year round it's got corn all year round it's an island so it's isolated this is the is the a typical corn production region for the companies and you can see it's like in a bowl it's surrounded by mountains they had used a lot of BT sprays in the past so these army worms had been exposed to Beachy before and the companies irrigated and these fields are very attractive so it was like the worst case scenario to develop resistance but what it showed was that it was possible for for some of these past to develop resistance to a transgenic crop and that's why it's kind of important. The second shoe to drop was root worm and it was closer to home in Minnesota and I've showed these pictures before if you've ever come to any extension meetings in the last few years this is a continuous cornfield that is essential e could not be harvested because it's laying its lying on the ground this was an Cry three B.D. for corn for corn root worm control for like three to five years and here is an aerial picture showing that this was the cry of three B.B. corn that is is a lodged and falling down and yet the corn that is there was. Planted in the in the remainder of the field is a is a her killer X. type of corn that corn was still standing tall so it this was a cry three B.B. One problem initially Cry three D.D. had been released first in two thousand and three and the Hercules corn root worm came I think three years later like in two thousand and eight or two thousand and nine so there had been fewer years of selection on this but but the Cry three B.B. was was a failing. When we see fields like this you have to respond to these damaged cases and it can be really difficult you got to take a field history and make sure that it's not compaction or some other problem maybe her herbicide issue you have to make sure that the corn is making the B.T.N. which means you have to have these check strips these are not cheap they're actually over a dollar each typically So for those for a public university we don't necessarily have a lot of checks trips or even just a regular business might might not have these you have to make sure that it was real corn damage and is it high enough damage to be unexpected because you do get some feeding on on the on the BT corn this this route that I'm showing you is quite bad and this was from a field in Michigan and then you have to take samples take pictures you have to report up the company chain which can sometimes be difficult and the most important thing that the company is supposed to do but it often times did what did not happen is you have to collect insects for a resistant screen and if you don't get out there right away then the insects disperse or you get a bad sample and for a roo worm it's extra hard because root worms first you've got to convince them to lay eggs and they lay eggs in soil and then you have to take the eggs and you have to put them in cold store. Ridge over the winter because they won't emerge in less they've had a cold period that's just the biology and so you don't start so you can't do the bio assaye on the population until six or eight months later so you have a real delay in being able to tell a farmer what what's going on so for the bio assaye we the we I don't do this but I have colleagues that do this they actually take some of the eggs of the larvae for example from a field if you if you had a problem and they put it on BT a non BT corn and they look for the for the damage by the larvae in in the pots so this can take a super long time. And if I got a question or not there but. There is one Chris China asked Can I. Go ahead John asked swing spraying for bugs are insecticides subject to alkaline hydrolysis possibly requiring an acidifier offering agent. For just any insecticide. So I mean if most insecticides do not like if you're thinking like. Like M.S. added with a certain herbicide applications and things like that for insecticides we usually don't think about adding these other other things to make them work better most of the time whatever it needs is is is in the formulation. So we don't usually unless you have extremely bad water and it says something on there's a recommendation on the label to add something most insecticide formulations would not need that though that's more of an issue usually with herbicides. Thanks Chris OK. OK so. When the insects from Minnesota were examined what they did was they took the insects and they from these problem fields and they put them on non BT corn and then BT corn and on the on BT corn of course they all they they both populations survive very well but on the BT corn only the population from the problem field where the corn is falling over was actually surviving and that's an indication of resistance the susceptible insects are dying out on the Cry three B.B. they're they're from a field that doesn't have a problem and these growers that had a problem they're insects are surviving and that's the classic definition of resistance so this popular these populations in Minnesota in two thousand and nine were resistant to cry three B.B. and that was the first case of resistance in the mainland US in regular Midwestern corn production so resistance so it turns out that root worms are very different from corn corn borers they're easy to work with they're. They have very rare resistance they like to distribute and made on the edges of fields corn root worms aren't aren't like that the the the BT corn itself was only moderate dose it was actually low to moderate dose so a lot of these survivors came out of the corn many of them were completely resistant and when they mate they like to mate right in the same field with their neighbors so you have cases of resistant and resistant matings would be a lot more common and Rouer Mysis dense to be developed very quickly because their biology was was different. This is a picture from Michigan this is a field that I visited in two thousand and thirteen and I was completely confused because it was heavily damaged it was it was a cry three A which was a different kind of BT for root worm I had never heard about resistance to it before yet they the plants were making a lot of BT they did pretty well this is the interior of the field that was all lodged and when we did the tests on corn where BT is absent of course. The Beatles from the the bad field and a neighboring field that's fine sir survive just just fine on Cry three A The Beatles from the from the resistant field were surviving so they were resistant to cry three A And they were also resistant to cry three B.B. It turns out that this farmer had used Cry three B.B. for a few years and then when them cry three A came out he switched to a different hybrid and what we didn't know it at the time but we know now is when beetles develop resistance to cry three B. B. They also are resistant to cry three A There's actually cross resistance there. So there's cross resistance between these populations and in fact there is cross resistance between all three of the proteins that are listed above so the Cry three B.B. One was a month's end. Product sold in Dekalb seed for instance and these other two proteins were us and gentle protein so if a bee little is eating one it's resistant to all of them and we did not expect that. So the current status of root worm resistance is there's resistance to everything beetles depending on where you're out specially I one Minnesota southern Wisconsin South Dakota North North Dakota these beetles are resistant to the original Cry three be either resistant to these Agnes or toxins and there are there's growing resistance even to her chillax corn root worm we have very isolated cases of this we're very lucky but on the Central Plains this is a widespread failure and a lot of people are just planting a root worm trait but essentially doubling up with the soil insecticide. This is just the resistance worldwide I mean it might not mean anything to you but you see a lot of arrows you see a lot of places lead up these are individual instances of. Resistance of insects to Bt cotton to BT corn in the Philippines. BT corn in South Africa Brazil and corn for and there's are Puerto Rico and then here is our U.S. there's just a lot more pests There are becoming resistant to BT. The last shooting drop was the Western being caught worm and this isn't our area we kind of pioneered this I guess it's a it's not fortunate but that's that's what happened so western being caught worm is native to this region and in the early one nine hundred. Does the pioneers went forth and planted corn and dried beans in this area and starting in one nine hundred ninety it has moved across the northern tier and it is now found all the way to the Atlantic Ocean and we found it in two thousand and six in Michigan for the for the first time so it's not a new pest to the to the north america but it it's new for us and in the documents that E.P.A. was given to register a lot of these B T's it was called a secondary pastor or it was never even mentioned. But at some point in think two thousand. Maybe two thousand and three or four Wester being cut were begins to appear on the cry one F. corn label and it's which is the Hercule X. corn label and in marketing materials not that there was data to show that there was control but that's how it was being marketed so this is the adult and you see the larvae the big the big and the small larvae. So two thousand and one is when the Hercules straight was introduced by Pioneer and like I said this is a corn bore toxin it was initially a corn bore toxin and again in two thousand and four. The Western being caught worm appears on the label of her kill X. with very little backup information or backup data it and it started to be marketed widely marketed as this past began to move west or east. So we had a few years where the population was beginning to increase as the pest moved into Michigan and then by two thousand and sixteen and seventeen we had seen some fields that were struggling to control Western CO or but these are just pictures from two that this is two thousand and sixteen. Of damage plus some of the extra air mold issues that happen when you get Western being caught worm. And these this is all corn that is testing positive for cry when F. This is the this is actually genetically engineered corn. This is an interesting picture that's from my colleague in Ontario is at a place called Bothwell which is over let's say between the Canadian border with the U.S. and Toronto it's maybe about halfway and it's a very sandy area that's much like parts of Michigan and the top layer of corn here this is non BT and it's all eaten up and full of mold from Western bean and a layer below it this is smart stacks from the same field and it looks just about equally as damaged and so smart Sachs has cry one F. in it so it was not doing its job and it was not stopping this insect. This is just some data that was from my colleague it Cornell and he happened to have a hybrid trial where he was looking at not at Wester being cut were but he was able to take data on that so he had a double pro hybrid that had these to talk sense and these do not control Western being Cut-Worm so we didn't expect any control and eighteen percent of his ears were eaten up. But he also had a Hercules hybrid out there and it had Cryo one F. it was expected to control Western bean and it had almost identical amounts of infestation this hybrid was a failure in this study he also had an egg or sure that Tara hybrid This has cry when F But it also has the VIP protein which was constructed or made not to control corn bore but to control some of these other caterpillars So it was expected to have control and it was perfect so this failure had to do with cry want to cry. Neff was what was failing not the hybrid itself this hybrid did just fine so we knew something was up with cry when F.. And furthermore we have some assaye data from my colleagues in Ontario where they do complicated little assays they take these little trays with little individual little These are called Wells little holes and there's a little artificial diet in there and they take newly hatched larvae and they place them in on to that food and see if they die or not and they what they can do is put varying levels of BT proteins mix them into the diet so this is how we do a bio assaye to see if there is resistance or not so this is a picture of the bio assaye for cry when asked on this artificial diet so here's the assay data for corn bore don't get wrapped up in these levels the this is like Nana grams of Bt that's put on the diet that doesn't mean much just look at the number this is the amount of or the concentration of the cry when F. that it took to kill fifty percent of the corn population and we use that as kind of like a measure of resistance so this is corn bore in contrast here's Western being data this is the amount of toxin it took to kill the Western bean larvae in the same assaye So corn bore four point seven port four point five west are being caught worm thirteen thousand twenty one thousand eleven thousand hundreds of times more cry one F. was needed to kill these so the cry one after was still killing the corn bores but it does not consider does not control Western being Cut-Worm and this data shows that probably cry when F. was never that great on Western being caught worm and we got survivors out there and it failed pretty rapidly. People have always have have also asked. Besides that not being a very good toxin is there something else that contributed to this and I'm kind of convinced myself that something also changed when we went to refuge in a bag so refuge in a bag is when you know you pour the core now and it's got the refuge mixed in to the bag and it's a different seed color Normally it's a five percent. Of that bag is the refuge so when before we had refuge in a bag you had to go plant a block refuge of of of five percent and I was lucky because I had an efficacy trial in two thousand and ten in my column County and this is the data from that trial where I happened to have a non bt that got all eaten up and eighty two percent of the ears in that non BT were damaged by Western being caught. And I had a gin new to smart stacks that was just the just the transgenic alone and I would have had to have planted a refuge and had I been a farmer I would have had to plant a non BT refuge in this case all this was was just pure BT in there and it had cry when F. and about only a third of the ears were damaged well here is the same product the Giannoulias smart stacks with the refuge added in so in this treatment five percent of my row or my seeds or my plot were non BT mixed in and I'm back up to seventy four percent of the years damaged so I think that this is and there are other people that have a observe this and this has been observed for other types of caterpillars as well when you have this little non BT spot in that field it's likely that larvae can develop on there for a period of time and get bigger and then when they begin to disperse around the field their. It is just not able to be damaged as well by cry when so I think that this refuge in a bag although it's very convenient for you. That I think it can pose a problem in developing resistance. And here's a really interesting graphic example of this this isn't my slide this comes from my colleague in Texas and he came up with a good way to show you. How refuge rose get contaminated so he just used this blue corn and pretend that this is the B T A R O A B T corn and that the yellow corn is there is a refuge row and you can see the cross pollination that occurs from this blue corn into these ears every single one of these individual kernels that turn blue is part of the cross pollination and that's a very good visual effect to show you that if this is a refuge row next to BT or this is a refuge plant that surrounded by BT most of this year is not a refuge year and a more it's in fact producing a certain amount of BT and that kernel and in fact it's probably a low dose of BT So any insect feeding here is getting exposed but not dying this is a recipe for resistance and this is what we've kind of created by going to refuge in a bag and this example with the blue corn just really pops that out so you can really understand it. At a couple of questions Chris OK Well we're almost done if we want to interrupt so my key messages to you is that BT resistance is now a reality it is a reality for our first keep test which is Route worm and for a lot of the second there. Repass like Army worm era warm and west western being Cut-Worm. Corn bore is still holding. But you know we've had twenty good years run with corn bore and resistance management can be pretty difficult we know that with corn bore resistance management plans that you you have implemented have worked really well we know that refuge in a bag has not worked really well for Western being Cut-Worm and we know that the twenty percent refuge for root worm probably wasn't enough so resistance management can't be done just with one percentage probably had to be species specific and because we're losing control by a lot of the B T's we kind of have to go back to the basics for roo worm its crop rotation crop rotation crop rotation crop rotation if you can get crop rotation into that mix anything you can do is better than nothing scouting and spraying for Western being and some of these other pasts is now necessary even on BT corn. You may have to and we should always spray when needed and not as insurance and the goal again is not a higher yield it's higher overall return so if you have a lot of failing hybrids and you're willing to go back to conventional corn and scout it and spray it. You may be OK if you're willing to substitute the ease of BT for the time that you spend with management. And this is my last slide if you do not know what you're growing if you don't know what's what's in a hybrid and you can't you don't know how to read a bag you're not sure how to how to read the bag tag and what just tries ECT mean or what does eggs sure R.W. mean you can go to the handy Viki tray table which I make and my colleague in Texas now made a home. For and you can look that up and on the backside of the handy table it lists all of the trade packages what's in them and what insects have shown resistance so I think that was my last slide and I have left time for questions OK Chris John Curtis has a question for you. Do you think the resistance to reform was due to not having the fifty percent refuge that was recommended. Well we can't go back in time but I can remember the discussions and this is all based on fancy dancy modeling they put stuff into models and out pops up a number of years that you expect it something to last and I can recall that the models showed that if you with the amount of up with the poor root expression of BT in roots and the amount of root worms that survived and came out of the ground the models showed you need a lot more refuge and it had to be fifty percent that might have delayed resistance but I think the bigger thing is that people grow continuous corn and put a lot of generate humongous corn populations and they don't go very far to mate and in the end you're kind of up against the biology of the critter and the continuous corn production that some people do and and you can see that where resistance developed first it wasn't it wasn't in our area or on the you know the ends of the corn belt it was right there in Iowa in Minnesota where you have the most intense corn on corn on corn production so it certainly would have helped. But I can't say for sure. Very good. And you can get a handy BT tray table. At this link. Yeah if you search handy BT tray table and if you google eyes it. Should pop up and you want to go to the Texas insect site because whenever I read we modify this pretty frequently you know we as something comes out that will always be the the the newest version OK so you can google any BT trait cable and look for the Texas look for the Texas like the other the other thing that is up on that website is we've actually posted a second file if you're a complete nerd and you want to read about all these cases of resistance we've actually I've actually made a list of all the publications because I got we got a lot of pushback from industry for including this kind of information on a on a table that there's resistance and so we put the citations in a separate file and if you're interested like where did Army worm how did Army worm get to be resistant and you want to look at that paper you can you know click you can go to that file and you could find that paper and and read the abstract. OK. Another question do do individual larvae and I think this was a corner. Western that were in question do individual larva feed on more than one place. Yeah they sow the larvae will start off on a plant and they typically go straight up and if there's a if there's a world though they will go sorry if they if there is a tassel they will chew into the tassel and eat pollen at first pollens nice like very you got a lot of nutrients and then they'll go down into the silk and that's probably an ten days worth the time when they're really little and you probably wouldn't see him but after that point they start to move and I have actually traced. Like a pattern of like six years in a row where you can see the first year and maybe a day or two later they went to a second deer and they went to the next year and the next year and the next year and then unlike the seven yr you open it up and that's where the larva is at so if you're a big fat larva and you are frosting or pooping a lot it makes very good sense to leave that infested place because you're Frasse is a middling a lot of volatiles and it's a sign for predators and parents a choice to come there so if you just pick up house every couple of days and move to the next year over it you're kind of the think about it you're at your escaping the wolves kind of so it makes sense for them to do that so they were damaged three to four to five years in a row a lot of times down the row. And the other question is for Chris. We've got her here. Not any other question insect questions right living today like how is my four A one K. going to do or something like that don't ask me how it's going. OK Well looks like you're getting off kind of easy CHRIS OK That's OK then we'll go on to the pesticide recertification credit information are you still with us Chris. OK maybe not yes I'm here sorry OK I was having technical difficulties. I want to thank you very much for spending your evening doing this and sharing your knowledge and insights. Chris is a marvelous resource for farmers in Michigan in these in these issues and I also want to thank my friend and colleague James T. Decker for being with us and kind of help me in holding my hand as I work through that evaluation program.