The History, Ecology and Management of Gypsy Moth In North America

for people that that will see this as a recorded version they will see that survey link and they’ll be able to access it even from the recorded version but I can look at the timestamp for when they access the database and and at least for the Society of American foresters they do not accept credits for an on live viewing of this presentation so so use that if you’re a certified forest or licensed forest or Master Naturalist whatever please use that hot line that will be disappearing when we start the presentation and the the bottom and the lower right hand quadrant you’ll see chat pod number for our speaker dr. Andrew libeled has inserted several websites related to gypsy moths and those are accessible for you and those again will also be accessible if you come back and watch the recorded version of this you will be able to click on those hot links so you can click on them now they should all open on the on the background screen of your computer they shouldn’t interfere with this presentation but those also will be disappearing here and in two or three minutes when we get started so and I’m assuming everyone can hear me okay Katelyn can Bob Stanley can hey James and Ron good sandy do you want to turn your microphone on and just do a quick hello good morning hey Peter I just turned it on so hi everyone great can everyone hear sandy this is sandy sounds like it works good amazing so explain how this works for you something right now I won’t so you can’t it sounds like a lie you can go back to the advanced settings and turn your microphone down try it down on like a 50 or 55 so go to the meeting meeting with an audio setup and then click all the way through to you get to the end and you have the option for advanced settings and then set your microphone level at 50 to 55 you or the participants you can look go ahead sandy yeah I just set it down to 48 as is yes well I think it is for those of you that thought that was loud before there’s Tim hi Tim so you can also adjust the volume on your speakers when we when I introduced sandy here in just a minute I will stop talking and so there will be a single speaker single presenter and you can adjust the volume on your on your personal computer or headset or whatever you’re using to at whatever a comfortable level is hey I’ve got about a minute till the clock says zero but that timer pod clock is notoriously inaccurate so just a quick reminder for those of you who are interested in a certificate of participation use the hot link in the left center portion of the screen and for those of you who would like access to some additional websites related to gypsy moth those are in chat pod number four in the lower right-hand quadrant we can bring we can bring those those pods back at the end of the presentation or you can check the the forest connects dot info website and the next day or so and this will be presentation will be the recording will be posted online and you can access those websites at that time as well so all right well let’s we’re gonna jump over to the main presentation screen and I’d like to welcome everyone my name is Peter

smallish I’m the New York State Extension forester based at the Cornell University campus in Ithaca we’ve been running the the program that I manage and direct is the forest connect program one piece of that is to run this monthly webinar series and we’ve been we’ve all been fortunate and benefited from having access to some really good speakers including today’s speaker who’s coming back for a second time and it’s my pleasure now to introduce sandy libeled he’s with the u.s. Forest Service in West Virginia and I’ve seen Sandy’s name in the scientific literature for decades dealing with about every aspect of gypsy moth ecology and management that you can imagine so he’s he’s been a player in a lot of different aspects of this base of insect and he’s offered to come and talk with us today about the ecology and management of gypsy moths North America so sandy I’ll turn the microphone over to you okay Peter well thanks so much I I really love the the format of this webinar from he it’s like a real luxury to be able to get a talk without having to get on an airplane so I think probably everyone else he feels the same way so it’s really a great thing um I’m gonna be obvious as the name would still be talking about Tripp seamoth and I’ve been working with this insect for pretty much most of my career which is about 25 years and it’s amazing it’s a very well studied insect there are probably hundreds of people who have done research with this insect over the last several decades so I think because so much is known about it it actually makes a nice model system and of course a lot of people I have to admit I actually like the one but I think most people who it’s probably not liked it so and I can understand that because there’s a lot not to like about it but oh one thing I was gonna mention you know if in those who participated before you know you can type in questions over there in that chat pod and I I’ll try to keep an eye on them and maybe I can address some of the questions as they come up or I mean I do have a lot of slides and work there so I may save some to the end and then also you you feel free to contact me by email you can just google my name and I have you know have lots of web pages plaster over the internet with my email address so feel phone send me an email okay so we’re gonna move along in the gypsy moth as probably most of you know it’s not native to North America it’s native to most of temperate Eurasia northern Africa and it’s that’s an example of a biological invasion in contrast to a lot of invasive species the the gypsy moth is its its pest in its native range that is that it causes problems where it’s you know it has evolved for thousands of millions of years because that not the cases a lot of insects say for example emerald ash borer which really is not a problem in its native Asia but is here in its the gypsy moth is an example of something that’s it’s a problem it’s exotic and native range um I actually have this little collection you can see if names from gypsy moth around the world my favorite is is actually this one the the see the none was a big head with just the name the gypsy moths Slovak so so and again gypsy moths being just an example of a much larger problem which is this continual flow of exotic species into North America and this is something that probably maybe no it’s particularly problem here in the Northeast that we have this is a map showing the number of non native forest pests and we have is from my for my last seminars Peter just it’s it’s a pretty map and I thought I chose an example the larger problem so I’m gonna jump in just a little bit of biology of the gypsy moth and one of the most important things that and maybe some of you may be familiar with a little bit with the troops that even though we do there just wants is considered a single species lie man tree at this bar but within its its range they’re kind of too strange that gypsy moth they recognize that the Asian strain and the European strain or the North American populations that we have originated from Europe and probably the biggest difference in their biology is the European strains most of the females are incapable flight and the Asian strains most females are capable of flight it says that means is that once we have here in North America are incapable of flight it turns out that this thing is not strictly just an Asia or non Asia thing in fact you’ll find

there are some places in Europe especially here in this overlap Reed is to refer to the Asian gypsy law flight capable but there is this tendency and I mention that um so just moving ahead with the life history the so the adults gypsy balls mate in the maybe mid to late summer and right after mating the female laser all four eggs on in a single mass covered with these spiny hairs usually the egg masses are are laid on the on the trunk of the tree but they can be on branches things objects in the ground and so then the they spend the entire winter in the egg stage and then in the spring is anywhere from like 300 to 800 so they have a very good capability of population growth because the large fecundity so the larvae immediately it’s actually done since the adults actually don’t feed at all and one thing I should point out is the the what’s the larvae get to be large they they actually just in most populations they just feed at night and and then come down out of the canopy and see cryptic resting sites like bark crevices or even in the forest floor we don’t really know why they do is complete but we tend to think that they’re somehow trying to avoid predators or parasites by doing this and so the then usually by mid-summer the larvae goes through their final larval molt and they enters the pupil stage which is the resting stage between the larvae and the adult and they tend to pupate the same location where the larvae rest that that they these shows typically on tree trunks you would see the PP the pupil stage it only lasts maybe a week or ten days or so so um the gypsy moth even here in North America there are many different natural enemies and of one group of natural enemies or virtuous parasitoid a parasitoid as a refers to another insect that it it’s it’s a parasite mostly the the adult they’re either flies or wasps they lay their eggs either the outside or the inside of a the larvae or pupae and then they lay their eggs in there the eggs hatch and basically turn it to a maggot that eats the inside of the it’s sort of like I always thought it would be a good subject for a science fiction movie because it’s kind of gross you can be watching a larva and all of a sudden this maggot comes crawling out of it but it’s very common pretty much all moths butterflies have these things and the gypsy moth most of these are not native to North America they were actually introduced at the turn of the century in an effort to to control the gypsy moth population via biological control and we don’t we think that they do contribute some control but they obviously are not totally successful in eliminating outbreaks um the other group of natural enemies it’s one that’s important or the pathogens and in virtually every gypsy moth population in the world there’s a call it nucleo polyhedrus viruses the virus it’s specific only to the gypsy moth and it it usually causes the collapse of high-density populations at you know when populations reach outbreak levels eventually this virus catches up with them you find larvae wilting on the trunks of trees in the last 15 years almost there’s a fungus which I’ll mention more a little bit later as come on the scene in it it has a rather similar behavior that caused the server wilting dizzy symptoms in the larvae and kills them so the the final group of Natron amines I was gonna mention are predators and most of these are what we call generalist predators which means they feed on many different species not just gypsy moths and and we know that birds will prey on gypsy moths but they’re not really a preferred food item for birds and some invertebrates like ants predications beetles but we there’s no question the most important predators and in fact probably the most important natural enemy at low densities are small mammals these are deer mice and shrews and we know that they’re capable of

eating many thousands of gypsy moth larvae and even though they don’t necessarily prefer gypsy laws but Ponchatoula populations are at low densities they are probably the most important to predator so in terms of of gypsy moths hosts again gypsy moth larvae feed on foliage and there we refer to them as a politican sauce or poly Fagin speeding that they have they will feed on species many different species of of trees and even though they they are poly feigus there certain species that they prefer and in North America oats are by far the most common preferred species but there there are other species such as Apple Aspen and other species that gypsy moth larvae do quite well on there is another group of species that are not necessarily we don’t call them preferred and it’s a little tricky to kind of define just a mouthful it’s preference because the the very young larvae tend to be more picky than the old that is the the the Yellow Turban will pretty much only feed on these preferred species like oak etc where’s that when the alarm you get to be large they can feed on a much larger variety of species so for example Eastern hemlock and some spruces can be fed or white pine are fed on and it just wants to do quite well on them Laden stars and in fact during outbreaks you may sometimes feet see the site like this hemlock that’s been completely full in contrast to most deciduous trees can tolerate getting defoliant at once because they’ll refund of most conifers cannot tolerate defoliation will die immediately so mandir certainly an addition to the the species of trees that gypsy lost where he’s tend to see egyptian health outbreaks the the types or associations of species that we most commonly see to field outbreaks in or of course in north america that once they’re dominated by oak so these would be oak hickory oak pine stands seem to be particularly sucessful outbreaks because these are drier sites and gypsum law seems to do really well on ridge tops this is something we don’t completely understand and then of course in more northern latitudes aspen aspen outbreaks developing there as well but one of the things is sort of a rule of thumb that we find that you really won’t get a gypsy moth outbreak developing unless you have at least 20% of the basal area composed of the preferred species like Oaks and Aspen that sort of thing so and actually one of the one of the people list the participants in our webinar today is Randy Warren who used to work here he actually made this map I’m so so proud Randy this is great anyway this is a map that shows the distribution of of these we’ll forest types in in the US and one of the things you can see is that and this this black line here represents what essentially where the district loss has spread so far from its introduction site period Boston and you can see it really hasn’t gotten to some of the really good places like the Ozarks so there’s no dog gonna be a lot of interesting things to come so for any of you have ever experienced gypsy moth outbreaks I can imagine you can have some interesting stories they they tend not to be a lot of fun that the gypsy wants because we’ve outbreaks call it you know they can cause see these impressive scenes have just you know thousands millions of acres 50 full Asian in a single year this is actually a shot from a couple years ago up in central Pennsylvania and it’s something and so every year that the Forest Service in conjunction with this with states they do aerial surveys and this is a map from 2007 and here’s just the number of acres defoliated in the last few years you can see the populations that actually our biggest outbreaks were the late the early 1980s and then the the early 1990s we haven’t had a really big one like those periods but ancient populations in general have been a little low slide but but the last few years the populations have have been up again I expect next year as the populations will decline in the east but we’ll see and in one of the things we affect one of the reason why I say they’re likely to klein is that when you look at the the time series of gypsy moths defoliation over a long time period they tend to have the serve boom-and-bust behavior that is there certain peaks or they’re very high and that usually won’t repeat they collapse and and they are dominated by a periodicity of about ten years although we do also know that in addition this

dominant ten year period is there’s sort of the sub-dominant five-year period azeez this is this is something where people like myself we spend a lot of time researching you know trying to figure out what’s the mechanism operating behind these population cycles and the population cycles are of course they’re kind of approximate they’re not it’s not like a sine wave but in general that the outbreaks did the the big outbreaks tend to be about 10 years apart 9 to 10 years apart so and as I mentioned before it probably will never really know for sure what really is the driving force behind the outbreaks but our our best theories these days are that it really is a results for a combination of two factors one is these generous predators which are I mentioned before the deer mice and they consumed large numbers of gypsy moths of low densities but there’s no real feedback that is if the populations go up the populations the generalist predators don’t go up and then but it and so eventually it just involves populations will reach very high densities and then they do hit some feed back and that’s when when populations get very high then you get pathogens such as the virus and fungus that eventually wipes the populations out and causes up to collapse so this is essentially I’m not going to know the details businesses from a type of simulation model that we many of one of many that have been used to describe to population dynamics and so the basic idea is that and when the populations are very low you have predation very high levels of predation by these generalist predators but then the chip sealants population slowly build up and then eventually reaching these very high levels and at those high levels the disease kicks in and causes the populations to crash back down to very low levels so that’s our theory of what causes these outbreaks to cause us boom and bust the dynamics to call this doom boom and bust behavior and I mentioned that in the virus there’s a gypsy most specific virus which is thought to be the main cause then of sort of the cyclic behavior it but and then you’ll find this virus everywhere in the world where the traditionalist exists but the in about 15 years ago that all of a sudden it was notice there’s a new pathogen of a fungus pathogen also causing killing large numbers additional population so different ministries actually to USDA tried to introduce it back then century in 1900 and they thought they failed it’s only only place in the world where it snowed the existence of Japan and then it’s all of a sudden it took off and it’s caused large amounts of mortality and in fact it’s some of the population so I’ll just skip over that this is some work that my collaborators and I’ve been doing up in central Pennsylvania and we go to some of these populations we don’t even see the levels of virus are actually quite low and where’s the the mortality from the fungus it’s called anti-mafia by mica or much higher so it almost seems some of these populations that the fungus almost these beasts are just taking them taking over the role of the viruses as being the agent that causes the collapse of populations but to be honest we don’t really know it’s gonna take us you know 10 or 20 years before we really understand the role this fungus interrupts dynamics um another interesting thing that we noticed when we look at edges lost outbreaks over large areas over large air time periods is this phenomenon of a spatial synchrony if you see this refers to this phenomenon where you you get outbreaks occurring over large areas in essentially the same year so you can see in this case the New England states around 1980 and again 1990 there are the synchronous outbreaks occurring in all these these states and again it’s it’s a complicated thing and it and again it’s a great topic for people like me and that like to study population ecology because spend several careers trying to figure out what causes this and it’s a phenomenon that’s actually common and a lot of a lot of different animal species and we tend to think with the gypsy moths that that it probably represents maybe the synchronization of populations may be mediated by the by the trophic essentially goes back to whether that is that you have variability in in weathers you have dry years hot years some new ways and and it’s fair in some years and not in others and these patterns extend over large regions and these weather anomalies can affect both directly affect populate defects the population dynamics in loss but also affected populations of the small mammal predators and and all in addition mass seating is it turns out that these generalist predators these small mammals are are their populations themselves are driven by mass seating that’s right someone has

commented that some they Rick ausf a lose narrow organ stops very nice nice nice work with this in fact actually related the the the stories even a little more complex because these small small mammal populations themselves are also influenced involved in in the dynamics of Lyme disease it’s a very complex thing so the consequences of gypsy moths outbreaks again there they really spectacular things when you see them and the conflict that consequences can become rather complex and one of the things that that can happen is is tree mortality as trees dying usually I would say basically the main take-home message on tree mortality is is that usually the mortality from most gypsy on outbreaks is not that expensive unfortunately there are a few exceptions where you can get catastrophic mortality that is where you’re getting you know greater than 95 percent of basal area being killed and these tend to happen in in pure oak stands and again it’s the exception rather than the rule but it does happen and when gypsy loss does kill a tree it usually doesn’t kill trees by themselves they’re actually altitudes mammoth really does is that weakens the tree which then allows secondary agents to colonize the trees one of those being our malaria root rot which is a fungal pathogen which colonizes the roots of Oaks and eventually causes the shutdown of those eylem the other is a insect the g-line chestnut or in the actually that for those of you are familiar with the emerald ash borer this is actually in the same genus as the emerald ash borer so but it’s native to North America and it’s not as aggressive as the emerald ash borer but in some ways is similar it’s basically what happens when you get Egyptian outbreak you get large numbers of these and these tree line Cheston pours their populations build up and and then they reach pretty high levels for sometimes four if you have a lot of stress trees their populations can reach pretty high levels and see you can actually have these insects starting to move on to even to some of the fairly healthy trees and so it probably sort of amplifies some of the mortality caused by by gypsy moth um so but but this is actually the result of a single study I just haven’t here just to point out the fact that usually the percent mortality is rather low especially if you only have one year of of if you just have one year of defoliation you might expect you know less than 10 percent of basal area to die and even with two two percent you may only expect a little bit more of what very often is very critical is whether we have other factors like say if there’s a drought there are a very few cases where where there have been a single year of deflation coinciding with a year of intense drought and those the tracers you get really extensive mortality but that’s again that’s the exception rather than the rule the other thing that you see is the trees that usually die are the trees that are gonna die anyway that is in most dance the trees that died following a single year FIFA lesion tend to be the trees in with poor ground condition and and or are suppressed and say those you may actually have very high levels mortality but the trees aren’t good good health are much less likely to die and so what really this results in this is you know turning additional output in most ants you would find that the trees that are gonna die are the ones that maybe would have died sometime in the next ten years anyway but because of that there have been you will sometimes see some either salvaged or and there are some guidelines available for for sort of pre salvage thinning to basically remove the these trees that are most likely to die before trypsin loss outbreak if that’s anticipated so in terms of the sort of regional impacts are really too many studies available but one of them that was done by Dave Ganz or back several years ago where he took some forest inventory analysis data from the Pocono Mountains and this is an area that received quite a bit of defoliation over a 10-year period and he looked at the chain overall changes in in in oak volume between two consecutive inventories over a 10-year period and actually he saw that for most of the Oaks the actual amount of volume actually increased even though and so this is even though there was more ten there’s no doubt there’s a lot of mortality happening in these stands but the main thing that was driving this increase in mortality increase in volume is that the surviving trees are getting bigger and and you also even get smaller trees that are reaching merchantville

ages so a none regional scale it’s very often difficult to say that that juicing oscillation really significantly impacts the overall yield of a species volume so probably a bigger question is well what is the effect on on the sort of next generation of trees and when you look in regenerate stance where there has been heavy defoliation and or heavy mortality this is again it’s just a single study that was done in central Pennsylvania and of course the what you see most of regeneration is good old red maple but and in the in the drier sites there you are getting a little bit of oak regeneration but in the wetter sites very very little and of course for probably most of your those are you’re familiar with Oaks silviculture probably realize that the overall problem here isn’t necessarily gypsy moth it’s causing this regional decline in oak regeneration but it’s probably other things such as grazing by white-tailed deer and if anything that gypsy lost defoliation may basically just sort of speed along a successional trend that’s already an in-progress process which is you know basically the conversion of these oak dominated stands basically converting to to not either non Oaks dance or music sites or the more xeric sites to have stands that continue to have some boat but but perhaps mixed with or of other species so the Gypsy malls probably speeds its process along but it’s not really the root cause of it so in addition to effects on on things like volume timber resources that I don’t have to be honest probably them that timber impacts are probably not them the main impact of the gypsy moth I would say the main impact is on homeowners that there is just sort of a thing about the gypsy moth is that it has these characteristics entrance during outbreaks you can get large numbers these are judith caterpillars crawling over this building or large numbers of cadavers of picnic tables so people just don’t like gypsy losses they don’t like having their trees in front of their houses defoliated there there are a few other things I mean for example water quality in watersheds and in there are a few cases where municipal water water departments have had to had to recommend boiling of water during an extensive juicing outbreak because what have one of the things that happens has been shown is that is that when you get extensive defoliation you get a huge flush of nitrate nitrogen going into the stream water and this in some cases can cause the pot coliform bacteria to bloom in reservoirs and this can be a bit of a problem so but the main impetus is really probably homeowners and people especially you know people who live in forested residential area not liking the defoliation and so consequently this brings us into the management side of things and and then I’m really going to be mentioning kind of three types of gypsy moths management we refer to as suppression eradication and so spread suppression which I’m going to talk about first really refers to try to reduce populations where you have an outbreak trying to prevent defoliation and this is usually done because it usually involves treating large areas the really only practical way to do this is with application of pesticides and so over the years of the amount of area that’s where the Forest Service I think I have another site after that toxins the Forest Service has a it’s called the cooperative suppression program and if you look at the acre sprayed over the years one of the things that but the first thing it jumps out is that the overall trends in from year 2 years are tracked the parent is sick Lissa T and the gypsy moths populations basically during the the boom years in in gypsy moth population since when they do the most spring which is not very surprising the other thing though is you can see there’s really been a big shift in terms of what’s sprayed and back in the in the in the good old days most the spraying was done with materials like seven with chemical pesticides and but what’s happened is over the years there’s been a shift more and more and to the point from now almost all the treatment arrows suppression that’s done is done for suppression is done using what we call PT which stands for bacillus thuringiensis and many of you are probably familiar with it it’s a it’s a wide spectrum bacterial pesticide that kills many different Lepidoptera species ban but it’s a very innocuous material and in fact it’s actually certified for use on organic crops because such a

benign material but yeah so the Forest Service actually operates through the foresters state private forestry has a program they refer to as the corporate suppression program which they carried out usually with with each state and they see and the details tend to vary from state to state in terms of the cautionary in all cases the Forest Service provides 50 percent of the funding for Erol suppression of gypsy moss outbreaks in states like Pennsylvania the the the state then kicks in I think twenty five percent and the landowner kicks in twenty five percent in West Virginia I believe the state doesn’t kick in anything so the landowner has to pay the other 50 percent but it’s basically a way that the Forest Service subsidizes aerial suppression of gypsy moth outbreaks and so in these types of programs usually the decision of whether to treat or not is based on the number of egg masses during the winter so if you go out so because again remember that the they spent all winter this egg stage so it’s a convenient way to to census populations so usually we do this in what’s called a fixed radius plot where we put in these circular plots and people go out into these plots so you put several these in your in a stand and each of those plots people go out and count egg masses either way up high on the tree or lower down on the trunks of trees and based on the other on the actual egg mass density we can then provide some sort of prediction of defoliation levels now one of the things when you look at this relationship it’s a pretty fuzzy relationship that is you can actually have a high a gypsy loss density and not get people Asian and so majal process of aerial suppress suppressing gypsy moth outbreaks really it’s a problematic thing it’s it’s it’s very difficult to predict affiliation it’s also difficult even using this BT it turns out with these suppression programs there’s a lot of trouble with with weather if it’s raining the BT doesn’t really work well if the timings off so it’s a problematic thing but but you know people don’t like to be in a defoliated area so there continues to be a lot of demand for these suppression programs I’m gonna the rest of my talk I’m gonna kind of shift gears and talk a little bit more about the invasion biology of gypsy moths and again with all biological invasions I think I mentioned this my other talk for those of you there we really usually recognize three phases the arrival establishment spread of an invading population and so if the arrival arrival basically refers to the basically that you know process by which the organism is transported to a new area such as a new continent oh yeah someone asked about predators the egg masses well maybe I might say that question to the ad because it’s an interesting question so the in the cases the gypsy moths we know that it arrived in near Boston in the town of Medford in 1868 or 1869 and and actually in contrast to a lot of alien species most salient species we really don’t know how they got there we may have a vague idea where they showed up first and we might have a guess how they got there in the case Egyptian Lots is rather nicing because we know exactly whose fault it is and it’s actually this guy a true valo who was a actually as an amateur he was an F professional artist but an amateur entomologist and he lived in this house in in Medford Massachusetts and as a hobby he liked to play with bugs and he apparently whose native of France apparently brought some back with him from France and was cultivating them in his backyard they got loose to give him credit he did actually notify the authorities about this problem but don’t really care until about 15 years 15 20 years later when the first outbreak appeared in his backyard and five or ten years later the government basically realized they really should do something about this so they mounted a large-scale radication program these photos they’re very cool I think are showing you know these crews of people that are sent out there to scrape egg masses out of trees it is a very gallant effort but you know the problem was they had pretty crude tools such as you know burning for infested forests and so they ultimately failed to eradicate the populations and so by 1900 the law was established in this area around around Boston and it’s basically since then it’s basically just been gradually expanding its range now people have been interested in in in monitoring the spread the gypsy moths and in fact interested in trying to stop its spread for many years there’s

actually a program that kind of started on again off again from like 1915 until about 1960 which was a barrier zone that was located along this mostly located along the Hudson River Valley and they used very primitive traps even back then they knew they’d put a female in a trap like this with sticky panels they could it was very sensitive method for detecting populations we you still use these pheromone traps although now we use a synthetic version of the pheromone rather than using a live female but so there was this large barrier zone along the Hudson River Valley and during that program it kind of morphed into different phases they and in the in the 1950s they started when you basically had two things you had the discovery of DDT and the the modernization of aviation and someone basically discovered you could spray DDT out of an airplane and and consequently you could spray large areas and so they produced this as part of this barrier zone effort but eventually there is a lot of opposition for those of you have read a Silent Spring you know the famous book by Rachel Carson there’s a whole chapter in there about the use of DDT for gypsy multiple control this is mostly from this barriers own project eventually by 1960 early 60s there is so much public opposition to the aerial spraying of DDT that this was stopped and so since then the gypsy moths really continued to expand its range when you look at this the only noteworthy thing here is that in Michigan there was an outlier population that became established in the mid 1960s and it was probably the only case where a isolated gypsy moths they basically failed to eradicate it they and that’s I you’re interested in the details and why that failure happened I could tell you but basically failed to eradicate it actually now the mostess main population in the Michigan population they’ve urged that we basically have one big population that continues to expand its range the fact that they they expand their range so slowly really can be attributed the fact the females don’t fly and and so several years ago we actually did an analysis of the historical spread and basically saw that in the early part of the 1900 saying spread around ten kilometers for you in from 1965 to 1990 or so we have spread around 21 converse but this period from 1916 to 65 we had rather slow rate spread around 3 kilometers per year and we feel that the reason for this is probably because these barriers on so the the barriers own efforts say they ultimately fail the Gypsy let’s continue to expand its arrangement apparently slowed its spread um now one of the things that the Gypsy Lots has this nasty habit of very often because the caterpillars crawl out of the trees during the day as I think I mentioned before to seek resting spots they very often become in contact with with human humans and their possessions so like vehicles it’s not uncommon to find egg masses on the other side of a vehicle that’s parked in an outbreak area and consequently every year we have life stages that are transported out to places like California and but every year the USDA and state governments put out over a hundred thousand traps in these uninvested states and these traps are really sensitive a very sensitive tool for finding these isolated populations so this basically brings up the service second type of trip self management which is detection and eradication so the traps are used to find of new isolated populations in places like California and then when they find a population you know indicated by positive trav captures they go in and and spray it in the following year these days most is treatments in these ice in places like California more distant areas or with bacillus thuringiensis the bacterial pesticide and again as I mentioned before virtually every one of them with this exception of the Michigan population has been successful and I don’t actually have the data I think they’re on average over the last twenty years we’ve probably seen there may be you’re probably there probably about forty or so eradication forty or fifty eradication programs so it’s a pretty big thing so so the final thing I’m going to mention is the slow the spread project and and I mentioned this is one of the things that there’s all these barriers owns were ineffective and at sewing gypsy mall spread but we do think that they did serve to slow slow spread and so there’s been renewed interest in this about 15 20 years ago and out of this interest came a new strategy for slowing the spread that

gypsy moths and it was really based on on something the rather basic thing about the way we know that the trips a moth spreads this is actually common to probably a lot of invading species that is simply when the gypsy moth expands its range it doesn’t just gradually expand but instead you have populations where you have populations essentially sort of jumping ahead and forming what we call isolated colonies and the the mechanism here is I think I mentioned before we know that things like recreational vehicles and movement of logs and things like this are ways that just amounts are accidentally moved and this is the way we think that these isolated colonies are founded um now many of these populations get founded way you know long distance it’s like California but but it’s it happens at an even higher frequency as you get it closer to this to this expect infested front and so the whole effort also spread program focuses on trying to find these isolated colonies because the idea is that that that the in models shows that if you can if you can find and nuke these I say colonies it will greatly solace the rate of spread of the gypsy moths and so the way we find them is using grids of pheromone traps and and basically these traps are deployed in a 100 kilometer band that extends all the way from the Canadian border to the Atlantic Ocean and it’s just referred to this as the gypsy moth slow the spread program or SPS and the whole logic behind the STS program is because some people I’ve heard you know told this is some people they say well why don’t you just let you smell get everywhere and get it over with you know it’ll be then you won’t have to worry about but the problem is is that gypsy loss outbreaks when it’s gypsy on this establish an area it just doesn’t arrive there and then you know you have one outbreak and that’s it what happens it arrives there and then you then have recurring outbreaks essentially forever and it’s a the way I sir he’s the logic so they’re basically the benefit of having this little spread program is you’re you’re delaying the year at which the gypsy moths will establish in your area so I sort of say the analogy of you know if I were to ask me whether I would like to have you know I was gonna have Alzheimer’s disease and that I was gonna I could you know I might have it either five years from now or I could have it 15 years when when would you rather have it and how much would you like to pay to prevent it and I’d be willing to pay quite a bit to postpone the date so it’s basically this idea that postponing it has values basically the logic behind it so the the the the biology here is again these grids of pheromone traps are put on at a two kilometer grid oh yeah someone has about temperature extremes it’s true that that to the far north it’s very farther in northern areas especially as you get into Canada two things happen one is he have very cold temperatures that limit the population growth of gypsy moths the other thing is he start to run out of hoes I mean you do have Aspen which is a good host but you do get into snake coniferous forests which are not good hosts but really the main thing that limits trips you must spread and limits the development outbreaks really cold overwintering temperatures which the egg masses just can’t tolerate um yeah okay so with the solidus spread program you know these grids of traps that are put out and every year and then when when the traps indicate the existence of isolated population more traps are put in to delimit the spatial extent of the population and then finally the aridness the Arias is treated to to the growth isolated population actually doesn’t shut usually in the neck the following year it’s then monitored with more traps again to see if the treatment worked um and that’s the gist we want so the spread program has been in place for as a national program all along the exten entire expanding population front since 1999 and in the big in the earlier years most of the treatments were done with BT Bacillus thuringiensis but now in the last five to ten years most the treatments have done these aiding disruption because this is something that you know BT does have a negative impact on things like potentially negative impact on it say for example endangered butterflies sometimes this is a matter of concern where it’s mating disruption has essentially no known effects on anything other than the gypsy Othon basically the way it works as these these tiny plastic flakes are sprayed from an airplane they have a little sticker so they stick the leaves and and then the he basically creates this huge cloud of the synthetic pheromone which then interrupts the ability of males to find females and and the populations essentially a go extinct it’s a rather amazing program though that the forests are is it’s the funding for it comes entirely from the Forest Service these spend about ten million dollars a year the the funds go to the

states along the expanding population front who actually carry out that work and so about half the effort actually goes into actually placing traps over a hundred thousand of these pheromone traps are placed along this expanded expanding population front hundred kilometer band and so each in this madness hawala shows up but each dot here represents one trap and so basically all the data is actually fed into handheld GPS is so it’s geo-referenced and then goes into a central GIS which is then used to to generate maps and identify areas that that should be that should be treated the question was how species specific this mating disruption it’s with in the case of just really we don’t know if any other insect that has that that’s affected by the that pheromone these pheromones tend to be quite specific in some cases in some other families of insects there may be some slight cross attraction it’s quite unusual so I would say it’s it’s pretty much completely species specific so it’s it’s pretty neat stuff and so actually the with a slow the spread program the weave from our historical analyses indicated that gypsy moths was spreading about twenty one kilometers per year and then the once there’s actually a predecessor program called ei IPM which was started late 1980s early 90s and since the and then that basically morphed into this slow the spread program and since that program is in effect it looks like we’ve been able to reduce spread by by more than fifty percent which and economists tell us that that has lots of value for people who live in like places like the Ozarks they’re really the people that are benefiting from from this kind of program so and I think that’s actually the last slide I have Peter so that coming up to right around 45 50 minutes yeah so I guess that’s perfect like I said we wanted I guess people can type in questions yes let’s so maybe we’ll have everybody can start typing in questions and I’m gonna rearrange the screen a little bit here so we can see the questions better and let’s do this Oh somewhat I do notice someone asked a question about so that because I mentioned about their mouth outbreaks tend to be most frequent in these Eric stands and and yes it really reflects both you know Roo because really it seems to be a soil moisture so it can be it’s affected both by you know that just the geographical things like you know rain shadows but and slope and aspect and and definitely soils as well very again there’s some other reason I think with ridge tops very often you have these we you know you have tend to have these dry sandy soils where you get these oak pine stands growing and that seems to be where the populations thrive and in fact my pet theory is why the outbreaks tend to be so common there is of course one is that’s the kind of places where you see Oh Oaks dominate but the other thing is the small mammal populations tend to be lower these are the predators again that kind of keeps evolves populations in check during low density years so if you have fewer small mammals and they’re probably more prone to to grow to outbreak levels um so somebody asked the question about how useful is it destroying egg masses in the winter um you know it really depends I would say on if you have an open grown tree because again you know the the gypsy laws they can’t the only way they can move away around between trees is by the the the caterpillar is either blowing in the wind is very young caterpillars the young caterpillars after they’ve hatched they spin down on silk and they blow in the wind so if two trees are very close together it kind of or say if you have a tree that it’s right next to a continuous forest with lots of just females populations it’s probably kind of pointless to try to remove the egg masses because the you’ll just get you know millions of caterpillars dispersing in from nearby forests but if it’s an open grown tree that’s quite a ways from another gypsy moth host then I think actually removing egg masses might actually accomplish something and and one of the ways you can accomplish this I mean a related thing that’s done is the use of burlap bands so you it’s something that people have known about since the turn of the century if you wrap a band of burlap around a trunk of a tree that the the caterpillars again they feed at night and come down they’ll find this broad band and they they think that it’s a really fabulous place to hang out and so you could actually go out there and actually pick the larvae off during the day and put them and say soapy water to kill them even if it

doesn’t do anything it very often feels good people you know it always feels people I think sometimes it’s nice to feel to have some you know some you call it getting even with gypsy moths so okay let’s see someone insists that arrow spraying somehow prolongs outbreaks but I don’t say connection yeah it probably doesn’t but you know there actually is there’s it’s not a completely you know again I think that in most cases arrow spring doesn’t prolong the outbreak but there may actually be a few cases where it does because what happens is you know usually the the population will eventually the outbreak will collapse when when the disease which is usually the the virus or fungus builds up in the population and and in order for that that disease to really get cranking to the juice smells population’s you need to have high densities and so if you you know if you reduce the density down you may actually prevent the development of that that episodic but I eat but I think the reason why it doesn’t really work necessarily is again because usually you know if you look at the places that are treated know whatever has we don’t have that no one has the resources to treat all gypsy moth outbreaks and in fact if you look historically we usually treat maybe it tenses it the area that gets treated as a tenth of the area that gets D foliated so so even if you treat one wooded area the the episodic will spread in from adjoining areas so so I I think in most cases arrow spring doesn’t doesn’t prolong the outbreak so so okay sometimes the question is and oh yeah temporarily interrupt for all the participants there’s immediately above the chat pod you’ll see a note to please complete this exit survey if you could click on that link so that you can open that exit survey it’s it’s essential that we get a high percentage of participating participants taking this exit survey so that we can document the impacts and continue to to be able to offer this it also provides me a very nice way to give some metrics to Sandi that he can share with with people in the Forest Service to you know to demonstrate his impacts and in an among foresters and landowners so that’s your it’ll take a couple of minutes but it it provides great mileage for us so so please do take that exit survey okay sandy sorry back to you know that’s a good idea I have it take the exit survey I have to send my kids to college so let’s see so is the females do not fly what is the physical mechanism by which the population spread well that’s a good question I mean so and we in fact we’ve done the the main natural mechanism that the gypsy moths have for first spreading or disparate wood dispersal the main you know natural dispersal mechanism is this first instar larvae blowing in the wind but there it’s actually a really hard thing to study but there have been a few studies of it and we think that in most cases you know 99.9999% of the larvae only go you know maybe less than 500 meters in a single in a single year and so if they and in fact our models show that if they were just spreading by this wind-borne dispersal of the young caterpillars they would only be spreading about two kilometers per year but we know they you know that they’re still they’re spreading you know I never between 10 to 20 or more homers period so we know the reason why they spread so much faster is because of this artificial movement of life stages that is people accidentally moving things like egg masses being actually moved on automobiles lawn furniture we know household moves or cut way they get around of wood logs firewood so that’s probably the most important mechanism by which they they disperse that affects spread so so let’s see so would you would increasing the number of snags increase the habitat for small mammals help even on the ridge top sites well that’s an interesting question and it really comes down to you know a question of what’s the kind of critical thing for small mammal to Hucky affect your small mammal carrying capacity and you know it may be something it’s an interesting thing and I you know I’m not a biologist I don’t probably don’t have hay for very good useful but I can still speculate on that but at least in some areas at some of the okk dominated stands the critical thing that affects the small mammal populations is the availability of mass

because it’s the small mammals Japan Don massed eg you know acorns to survive the winters they cache them and so of course the ironic thing is the thing that that that is good for the small mammal populations is to have a lot of Oaks but then of course the you get large on the more Oaks then you know of course that’s more habitat for gypsy moths but so but I know we’ve done studies that you can actually if you feed the we’ve actually artificially provided food for small mammals over the winter and you can elevate the small mammal populations and and also increase the mortality in gypsy moths but none of the things like there’s never been any evidence that you know things like creating more cover or snags really affects the small mammal population so I’m aware of it but it might be an interesting thing to look into is um let’s see someone asks is it important to trap for gypsy moths in areas with established populations for example upstate New York to monitor population actually that’s a really good question I’d say the quick answer is no and which is a sad thing because and the reason is that for some reason and this is to be honest is a little bit mysterious even though we know did these pheromone traps are really effective tools for detecting and measuring populations when at the expanding population front for some reason the actual correlation between trap catch and actual local population density it seems to fall apart once the populations become established over large areas and I I’m not really sure why that is it may have something to do with dispersal of males that it sort of mixes up the population so basically the the there’s been a lot of work that’s gone into trying to use pheromone traps for monitoring populations in in places like New York where it’s been established everywhere and it they just don’t provide very useful information and so instead the the standard method for monitor populations in infested areas such as like New York Massachusetts would be via permanent plots where you count egg masses that is you go to the back these permanent plots that you count the number of egg masses say no fortieth acre plot the problem is they’re not very sensitive at low densities you go to if you have these plots most years you will get zero egg masses but that doesn’t mean the populations extinct it’s just they’re very low densities so but they still will give you at least one year lead usually on whether the population is rising in some states I know Massachusetts does have a network of permanent plots where they they count egg masses and the idea is it provides you a little bit of a early warning so you can start to see populations rising before they reach defoliating levels let’s see is yes so if 15 without breaks are not considered creating a negative impact on forestry is the forest or spraying to protect forest recreation areas rather than marketable timber well first I would say it doesn’t have any effect on timber it’s just that when you when you look at the economics the economic impacts on on residential land is is probably greater than the impacts on on forests impacts in fact I mean I’ve seen some studies say that the the you know again the impacts on timber they’re not zero and in fact they may in some cases justify aerial suppression however I would hazard a guess in most situations they probably don’t and so so yeah the answer is is that in most cases the aerial suppression is really targeted at places where people live so most of the state again the Forest Service doesn’t have such strict rules but most of the states would actually carry out these programs do you have and I know for example that Pennsylvania will not allow you to participate in the cooperative suppression program if there’s not a house in a area in fact there has to be at least one house for every I can’t remember the number maybe every ten acres or to qualify so in other words you can’t get the cost-sharing if there’s not a house nearby so so let’s see the next question so if if we have traps to monitor populations why don’t we have traps to sell why don’t we have traps to sell commercially well actually they just sell transfer you go to area hardware stores and you can it go on the internet and buy your pheromone traps but again the pheromone traps are not going to be useful well a one things pheromone traps are not useful for control at all so you mass trapping has been attempted it’s very difficult to get mass trapping to work and it definitely if it works would only work in these very isolated populations where they’re very low

densities like for example I mentioned with the spread program uses mating disruption that only works at very low low low density populations so in places like New York Massachusetts where channels have been established mating disruption and mass trapping won’t work at all so let’s see what about the common practice of burning the tents or nests in trees ah yes this is one something I should have pointed out gypsy moths do not make a tent in trees they don’t they they make they do produce silk but they produce very um you don’t usually notice the silk produce so normally the when you see many times there’s confusion between the gypsy moth with other insects like there’s the fall web worm and caterpillars and their infect particularly the tent caterpillars the larvae look very similar to gypsy out there they’re hairy and they have colorful stripes spots on them but they’re native insect and usually they’re outbreaks are much they’re not as extensive and so it can’t count for states and places like in Minnesota Wisconsin I believe parts of Michigan you do have some pretty extensive outbreaks where there’s some aerial suppression that’s done but in in the New England states and central Atlantic areas the the tent caterpillars and fall web worm the damage I would say is usually negligible I know Allegheny plateau there have been a few outbreaks and again in most areas there haven’t been a precursor are negligible so and even with fall web worms if you have them in your property I know there’s this thing about burning the tents but I always instruct me as sort of a dangerous thing to do I mean you I actually do that in my property I’ll go in and actually manually prune to remove the colonies but again those aren’t gypsy moths but but it’s some of that can be useful let’s see are there studies on impacts from BT non-target LEP’s yeah that there have been in fact it’s a really good point that that the the BT does have some negative impacts on native lepidopteran so as a result very often many areas you really can’t use BT because if there’s an endangered species of Lepidoptera of and so that’s it’s a really important concern and I one other thing I should point out is that there’s another product called JIP check which is it’s a formulation of the naturally according to P mouth virus there’s very limited quantities available it’s not available commercially only the Forest Service Forest Service makes about enough to treat someone retain ten and ten thousand of 20,000 acres every year and but it’s the nice thing it’s very specific to the gypsy moths and doesn’t have effects on non targets Peter I notice if we’re actually at at one o’clock or all past do we can we keep going as long as you’re available we can the you know the site is gonna be open all afternoon in theory we could go we could go two hours if you wanted let’s probably another yeah over ten minutes and then we can release people from there okay to get back to the rest of sure yeah so renee has a question about that mouse brain in Orange County New York yeah I’m just me a little person was trying to recruit folks to chip in for aerial spraying an Orange County nerd good idea or bad well again it you know this is something because this is what happens with very often sometimes it’s do the coop suppression program in which it’s usually done through and again it varies with each state on absolutely sure in New York out have some I believe in New York does actually not participate this is a state-level decision will state and lower decision since the last I heard New York doesn’t participate in the cloth suppression so that means they’re not getting any subsidy from the Foreign Service so instead of it it would mean that in some municipalities or even sometimes private landowners will go out and contract with aerial operators um the one thing I would urge a certain amount of caution a certain amount of caution of having just individual landowners contracting with private applicators because there’s you know actually carrying out a aro suppression program can be kind of tricky and particularly if you’re using bTW the timing has to be really perfect for it to work or otherwise it’s pointless of so I would say it’s better if you can get some government agency involved I mean whether to do it or whether to treat or not you know if it’s a if it’s just a purely forested area I suppose if it’s a super high-value oak resource you know same veneer trees and there may be some value in it just in terms of timber impacts but probably

most most most cases probably the timber resources don’t justify the aerial treatments in a forested residential area it really comes down to the homeowners and and very often you know for those of you experience it’s not fun living in a gypsy one because you know you have trees you know you’ll have total defoliation of trees which can you know young trees very often can’t tolerate defoliation I mentioned before conifers as they get defoliate as can completely die so something that a lot of us you know that I can definitely understand why wanting to treat but if you do do it I would suggest getting because Aero treatment it’s a tricky thing to do again because the timing and what material use some of the aerial applicators are not necessarily knowledgeable and there been a few hopefully exceptions where there have been you know somewhat unethical operators taking people’s money and not really and basically treating in a way that’s not likely to have an effect so I would try to do it something where the county or local municipality at least is involved so let’s see the next one so the best method for to control by individuals is either to scrape off egg masses and winter or to put the canvas traps on trees and collect larvae um well again it depends really what’s the situation if this is Justin your yard and it really depends on how big your trees are if your if your if your trees are small enough you can you know say if they’re less than say 30 feet tall you can even use a one of these sprayers that hooks to your garden hose to get to the top of the canopy and apply a BT usually you could go to your hardware store and the BT is sold under the most common name is Thoreau side or Dipel or for Ray and you’d have places by I’ve seen it seen for somebody’s in places like Lowe’s and Home Depot don’t sell its you have to go to maybe more of a good garden shop and they’ll have it usually and it’s usually a material you mix with water or you mount the thing directly with your garden hose you can spray up into the canopy of a small tree if it’s a large tree you’re not going to get up in the canopy and so then then you’re either going to deal with either arrow spraying or sometimes you can get pest control companies will have one of these large hydraulic sprayer so we’ll get up into the canopy of it of a tree but again the timing is critical and so again if you’re using BT once that you get past say the third third instar it’s not going to be effective so essentially once the caterpillars get to be larger than say a centimeter in length you can forget about using BT you could use something like you know seven or dim illan but you know those are probably going to have bigger effects on other organisms so so it’s you know kind of decision make the scraping off egg masses and putting wrap Bank cart but you know bounce on trees on the trunks is something that probably you’ll find to be less effective and again it will be most effective if you do it on an isolated tree if it’s a tree growing in a canopy with other trees it’s probably not likely to be effective at all or so let’s see there’s last question or Ted capper gypsy Ellison competition for the same foliage and does it mean anything well it’s an interesting thing I mean mostly the answer is yeah yeah some cases although that in most areas in say the mid-atlantic states they’re usually not the tent caterpillars are usually feeding on black cherry is usually their most preferred species and gypsy moths it’s not a preferred distribution species for gypsy moths so I’d say the mid-atlantic area they’re not competing when you get up into the northern areas like up in in northern Minnesota Wisconsin these areas you do get in in Aspen and birch you can get tent caterpillars and and gypsy moths and they’re gonna compete for the same foliage which and to be honest we whoever really feels it’s just now spreading it to some of these areas for the first time so we haven’t been able to see what happens I mean from ecological standpoint it’s kind of interesting to to think about of what is going to happen because again the tent caterpillar outbreaks these areas are somewhat cyclical the gypsy moths outbreak should be too so be interesting to see how they interact we don’t really know so well Peter it’s 110 and it looks like we got the last question so do you bring this to a close

thank you very much sandy this was a great presentation and you covered an enormous amount of ground and you did it very smoothly and gracefully and I appreciate knowing more about gypsy moths although I don’t like them any better but uh but I’m I’m informed about them so with that let me I’ve put your e mail address so folks can can click on that and send you an email if they like and we’ll officially call this to a close and Sandy I will see you back here I’ll be on by 6:30 or 640 tonight and you can join sometime in that 6:30 to 6:45 650 window and and we’ll have another go-around of this at 7 o’clock tonight good it’s absolutely the happy hour I hadn’t thought about it like that that’s that’s a good marketing tool well it just stinks yeah I was just gonna say thanks to everyone I is very nice questions if anyone wants to contact me feel feel free to send okay with that I’ll officially close the webinar and wish everyone a good afternoon thank you all Thanks