USACE ERDC. Moderator: Courtney Chambers September 16, :58 am CT

Transcription

1 Page 1 USACE ERDC September 16, :58 am CT Courtney Chambers: Hello, everyone. I m Courtney Chambers from the ERDC Environmental Laboratory. I d like to welcome you to this Webinar series hosted by the Army Corps of Engineers invasive species leadership team as well as the aquatic plant control research program. This series is intended to share topics of concern on invasive species issues across the Corps of Engineers. The Web meetings are recorded and our archive files are going to be posted on the EKO and the natural resource management gateways invasive species pages so you can reference those at a later time or share with colleagues that you think would benefit from viewing. Okay, just a few reminders before we begin our presentation today. As a courtesy to all of our participants, please remember to keep your phone on mute and also be aware that during the presentation I m going to apply a listen-only feature that s going to mute all participants until we begin the question-and-answer session. Following our presentation today, you can take your phone off of mute and ask your question verbally or if you re more comfortable utilizing the chat feature, you can type your question in the lower right hand corner of your screen.

2 Page 2 And please note that you can select to send your question to everyone which is preferable if it s a question about the topic today. If you have a question about some technical component of the meeting, feel free to send that message just to me, Courtney Chambers, and I ll help you. If you re having trouble being heard at any time during the meeting or have a question or comment and need help getting heard, feel free to select the raiseyour-hand button that s located just under the participants list on the righthand side of your screen and that ll let me know to address you. Please do not put us on hold with background music at any time during our meeting so we can limit our distractions. Lastly, if you re calling-in with others, please take just a moment to identify your organization and the number in your group by sending me a chat message. I would greatly appreciate it. Thank you. At this time, I m going to give you today s speakers. Dr. Kurt Getsinger and Dr. John Madsen. Dr. Getsinger has been studying the biology, ecology and management of aquatic plants since 1973, focusing on chemical control of submerged, floating and emergent invasive species. After staff appointments at several universities, he began his federal career at the U.S. Army Engineer Research and Development Center in Vicksburg, Mississippi in Since 1988, he s been the research leader of the Chemical Control and Physiological Processes Team at ERDC. For the past six years, he s conducted herbicide evaluations against the invasive flowering rush. Dr. John Madsen, our second presenter or co-presenter today is a research biologist with the U.S. Department of Agriculture, Agricultural Research Service Exotic and Invasive Weed Research Unit in Davis, California. Dr.

3 Page 3 Madsen has been involved in research on the ecology and management of invasive aquatic plants around the country for over 25 years. His expertise includes studying the ecology, life history and phenology of invasive aquatic plant species and developing management approaches to target specific life history stages of these species. He has also worked on methods to measure plant communities using these techniques to both assess the effectiveness of operational scale management but also evaluate the impacts of management on native plant communities. More about both of our speakers can be found in their bios which are posted on the invasive species Webpages that I mentioned earlier, along with today s presentation and recorded meeting. Gentlemen, we are very pleased to have you sharing with us today so at this time we ll transition to your presentation and I will enter listen-only mode. Operator: All participants are now in listen-only mode. Kurt Getsinger: Thank you, Courtney. Courtney Chambers: Certainly. We re hearing you and it looks great. Kurt Getsinger: All right. The research objectives for this work are to link phenological data, life history events of flowering rush, with chemical control strategies and we re focusing on attempting to control flowering rush both in its emergent growth forms and its submersed growth form. We re focusing on growing plants under mesocosm conditions to determine those weak points in the plant s life cycle, verify those mesocosm results in

4 Page 4 field populations and then to utilize the results of the phenological event studies to improve to improve the efficacy of herbicides against flowering rush in the field. So with that brief introduction, I m going to turn the floor over to Dr. Madsen and he s going to speak for a while on life history events and biology and phenology of flowering rush. John Madsen: Thank you, Kurt. Flowering rush is an aggressive invader, non-native invader to shallow-water habitats and water resources what we refer to as the littoral zone, the area that will support rooted aquatic plants. It grows from the shoreline out to at least three meters deep. It can also invade up onto the shoreline into moist soil habitats. It can reproduce in part by seeds but the formation of rhizomes and growth of rhizomes and rhizome buds are very important to the propagation and over- wintering of this species. It can also form a vegetative propagule known as a bulbil. I ll talk about that a bit more in a moment. It can grow in both quiet water and in flowing water. We see it both in lakes and in rivers. It s very adaptable to a variety of aquatic environments. The other thing and this is particularly important in the West, while it can grow in lakes that have a very stable water level, like the Detroit Lakes of Minnesota that the water levels maintain within a foot or so of the mean level, it s also very well-suited for growing in reservoirs that have widelyfluctuating water levels such as many of our Western reservoirs where the water levels can fluctuate 10 feet or more during the annual cycle.

5 Page 5 Why don t we go to the next slide, Kurt. Flowering rush is interesting biologically. The scientific name is Butomus umbellatus and it s obviously been known for a long time because it was named by Linnaeus himself but it s a member of its own family, the Butomaceae and if there is anybody from England listening, I apologize for how I pronounced that. But this is the only species and the only genus in that family so there s nothing else quite like it, but it is in the plant order Alismatales which means it s more distantly related to the arrowhead species of the arrowhead family; so let s go to the next slide Kurt. Flowering rush is introduced from Europe and Asia, the plants that are commonly found are probably mostly from Eastern Europe. There s two biotypes in U.S. - in North America I should say - there s a diploid biotype and a triploid biotype that for those of you who are familiar with different ploidylevels of plants. As you might expect, the diploid biotype produces large number of seeds that are fertile so a diploid plant can produce over 20,000 seeds and it ll also produce a vegetative propagule up in the inflorescence referred to as the bulbil. So if you look on that picture on the lower right-hand side, that s a cluster of bulbils around the inflorescence of a flowering rush plant and many of those bulbils will actually start sprouting while they re still attached to the parent plant. Work that was done on diploid plants was done in Southern Canada, in that peninsula of Canada that sticks down into the U.S. and it was done on the diploid biotype.

6 Page 6 The triploid biotype again as you might expect from understanding ploidy levels produces very few seeds and while it does produce those bulbils up in the inflorescence, the number that are produced are much lower. It relies almost entirely then on the formation of these rhizome buds so the upper right-hand picture just about where I think there that s a bud on the rhizome. That ll produce either a new branching rhizome or a new ramet of leaves so that are actually an inflorescent. That s a very important structure in this species and it s a key - I would say it s the key - propagule or the key life cycle stage in trying to manage this species and I ll get to that more later. Let s go to the next slide. Flowering rush is distributed now pretty much across North America from East to West. It s in the northern tier states of the United States. It s in most of the provinces across Canada. It is an invasive weed that doesn t respect geographic boundaries - I know I ve talked to some folks in Alberta that are trying to manage flowering rush - and certainly there s problems in the Western states, Washington, Idaho and Montana. I ve worked on flowering rush in Minnesota and a lot of the research was originally done around the Great Lakes particularly the Eastern Great Lakes. Initially from what I d heard in addition to the diploid populations to the Eastern Great Lakes, there were two populations in Idaho that were determined to be diploid. And I ve since found out some recent research by John Gaskin who s with USDA in Montana working on the genetics of this species. He s determined

7 Page 7 that in fact all of the Western plants let s say in Montana and west are genetically identical. And while he hasn t done the ploidy levels yet, that would seem to suggest that they re all triploid and not diploid populations as I had previously been told so we know for sure that there are triploid populations in Minnesota, Montana, Idaho and Washington and I think more will be coming-out on the genetics of this species across North America. Let s go to the next slide. As I mentioned the plants propagate and spread by pieces of the rhizome and the rhizome buds on those rhizome pieces like Kurt s pointing at there and then the diploid seed formation and bulbil formation are also quite important. The plants we re working on are going to be triploid so primarily the rhizomes and rhizome buds are the important thing. Those rhizome pieces can be spread by boat action, the wake produced by boats will dislodge them and they ll drift in the water. Wave action will likewise dislodge these pieces. Quite often you ll see the initial population will be formed right at the water level where rhizomes have been blown-up onto shore or drifted up onto shore and established. And then lastly the waterfowl here is not indicating that the waterfowl eat the rhizomes and then transport them but rather in the process of pulling-up rhizome from the sediment, they leave pieces that are too big to eat like that piece on that lower right-hand corner. The picture on the upper right-hand corner, that s Tom Wolfe with Idaho State Department of Agriculture. We were doing a study out on the flats of Pend Oreille Lake in Idaho and the, well, several years ago anyway and, you know, when we first pulled-up a flock of geese got up and flew away and we could

8 Page 8 see evidence of the geese walking around, pulling-up of the rhizomes and leaving them on the surface. So let s go to the next slide, Kurt. The plant forms very dense monocultures. The spread of the rhizome is such that while it doesn t form new clumps far away, it tends to form a dense stand right around where the initial population is and it forms what s almost like a piece of turf, a very dense-packed rhizomes and densely-packed culms altogether. So it forms these very dense monocultures whether we re talking about Minnesota like the lower left-hand picture there or I think all the other pictures are of Flathead Lake in Montana so let s go to the next, that s good so flowering rush the dense stands exclude native plant species. They reduce the biodiversity in aquatic systems. They can degrade fish and wildlife habitat. They reduce critical habitat for listed species so they ll displace the desirable species. In areas of the West these plants have infested irrigation ditches in irrigation districts and they ll obstruct the flow. Water in the West is very important for irrigation and other uses. They ll interfere with navigation and recreation. They ll obstruct the use of the waterfront so particularly we re working on Detroit lakes, there would be these dense bands of flowering rush growing right outside the beach area and obviously people were not happy about that and it ll tend to reduce the value of waterfront property. So the two areas that there s significant information gaps with flowering rush is first of all we need a better understanding of the life history of this plant across the growing season. That s sometimes referred to as the phenology of

9 Page 9 the plant and using a phenological approach where we observe the transitions of the life history stages of the plant. And we look for particular cues like flowering or fruit formation or the appearance maybe of bulbils or other stages in the life history that are easily recognizable and we can compare that to what we know about less easily observed traits such as the dynamics of starch or carbohydrate storage or the production of rhizome buds or other events that are of importance in the life history of the plant. We ve used that phenological approach to improve the management of a number of other aquatic plants, sometimes quite dramatically like with curlyleaf pondweed where by targeting the time management before turions are formed, you can dramatically impact the population of curlyleaf pondweed. The second area is that there are no reliable long-term control strategies including herbicide use. There s been a lot of sporadic efforts to utilize herbicides, to manage flowering rush but the information has largely been anecdotal and has not published in peer review literature. Kurt and his team recently published a couple of papers at the mesocosm scale and then the laboratory scale of herbicides that were effective on flowering rush but you need to take that next step of how can we implement those into a long-term control strategy for flowering rush, targeting the rhizome buds and reducing the rhizome bud population. Let s go to the next slide. Flowering rush is very interesting as well in that it can grow quite happily as a completely submersed plant like the picture on the left and then sometimes

10 Page 10 quite unexpectedly will form these emergent leaves. The submersed leaves are very limp, almost like water celery so they ll be quite flaccid. The emergent leaves will be quite stiff and they ll stand erect out of the water and anatomically the two leaves are virtually identical. They both have an epidermis. They both have a cuticle layer. They both have stomates so this transition between the two at this point is largely not understood but it does have significant implications for management. Let s go to the next slide. The plant reproduction can be from the formation of new rhizomes, the formation of rhizome buds, the formation of those bulbils on the inflorescence on the upper left there and then through flowering and the formation of seeds so the seed of the plant as that photo in the center but the seeds are only a significant form of propagation in the diploid plant. So let s move to the next slide. There has been one phenological study done in the field that was done by Michelle Marko of Concordia College and myself on the Detroit lakes. The plant production of rhizomes, the rhizomes don t die back. They re pretty persistent below ground but the leaves follow a very discrete pattern where they ll tend to sprout and to spring out of the rhizome buds that in the Detroit lakes appeared to happen in April probably even just as the ice is coming off the lake, biomass will growth quite rapidly. It hits a peak in June to July and then about the time when you start seeing flowers but the plants that are dying back don t have to actually flower. You start seeing a decline of biomass, the leaves will start browning and they eventually did back.

11 Page 11 The interesting thing is that they will die back even without a hard frost so there appears to be some sort of a photo period cue or a temperature cue and that s something that we can examine wherever the plant is growing. The rhizome buds sprout in the spring. They reach maximum biomass in the summer then as fall forms you tend to see an increase in the number of rhizome buds form and you see a decline in leaf biomass and then the leaves die back as winter approaches. Let s go to the next slide. So management of this species in my opinion must be directed at the population of rhizome buds, reduce the number of rhizome buds and prevent the production of new buds and any control technology has to address the rhizome bud issue whether it s biological, chemical, botanical or physical controls. We ve done some work on Detroit Lakes monitoring rhizome bud populations and looking at the effect of herbicide treatments on reducing the population of rhizome buds and it so far appears to be a fairly successful strategy. We need to see how that would apply using other use patterns or other management techniques. Let s go to the next slide. So our research is first going to look at the seasonal timing of the plant of the growth stage, production of propagules and the allocation of carbohydrates or the storage of starch. Let s go to the next slide. As you may recall the leaves produce sugars through the process of photosynthesis. The sugars are translocated to the rhizome. In the rhizome this is occurring in the summer and the rhizome, the sugars are converted to starch for storage.

12 Page 12 The sugars are converted to starch for storage and then in the spring when growth is starting and the rhizome starch is converted to sugars, the sugars move up into the leaves and those sugars are used for the leaves to increase in length and build structure. Let s move to the next slide. So the seasonal dynamic we ve seen thus far is that in the spring as the leaves are growing, the storage starch in the rhizome is turned into sugar and that material is used for growth. As you get into summer photosynthesis is able to produce enough storage or enough sugars for the metabolic needs of the leaves. And when you stop using stored starch and start storing a new year s selection of starch, then towards late summer you ll start seeing a continued movement of sugars down and into the rhizome and starch levels increasing for overwintering and then in the fall as the leaves senesce photosynthesis obviously halts. You have a high amount of starch rhizome and that s how it will over-winter. Okay, let s go to the next slide. We tend to see with perennial plants is that there will be a low point in the storage of starch and this is often a point at which we can target management whether it s chemical, mechanical or whatever. Carbohydrate storage is important in three ways. The low point itself can be a good time to target management because the plants will have the least amount of material to regrow. Secondly, by following starch dynamics it using a contact herbicide or harvesting and you can see how many times you have to manage to deplete starch storage.

13 Page 13 And the third thing is by understanding what time of year sugars are moving from the rhizomes up to the leaves versus when they re moving from the leaves down to the rhizomes. That has implications for how much translocation of systemic herbicides you ll have because with the flow moving from the leaves down to the rhizomes you ll tend to get better translocation that the other direction. Let s go to the next slide. So we re going to study different flowering rush populations and mesocosms, not these mesocosms but some sort of mesocosm at the U.C. Davis aquatic weed research lab. We re going to look at some different populations and monitor their growth throughout the seasonal cycle. And record temperature so that we can utilize degree-day relationships to describe or model various life stage transitions so let s go to the next slide. We ll then verify the phenology of those plants by monitoring populations in the field either on a quarterly basis or every other month basis. Okay, so that s why we re going to be more strategic in when we sample to try and compare back the stages and the temperatures that we re recording there with what we re seeing at the what s called the common garden experiment at the Davis facility. By the way the picture on the left there is Chip Welling of Minnesota DNR and he s holding a mat section of flowering rush. That s a piece that s almost turf-like or a piece of sod of flowering rush that he s pulled-up from a mat in Detroit lakes. Okay, let s go to the next slide. Actually I think I m turning it back over to Kurt now.

14 Page 14 Kurt Getsinger: Yes, thanks John. As you can see from John s review, we re dealing with a plant that has a very complex life history and can grow and survive in a wide range of habitats and of course that always makes things more difficult to manage regardless of the technique you re using. For the next few minutes I m going to focus on our efforts with management using herbicides and there are several factors that we have been learning as we ve worked through some of the scenarios over the last few years. For instance, we know the depth of inundation of the shoots is going to play a role in how you manage with herbicides. We ve had some success - limited and short-term - with submersed applications using contact products, primarily with diquat, but again that s a short-term seasonal control scenario and certainly doesn t provide complete control with one application. The problem with submersed applications centers on water exchange processes that can reduce the success with longer-acting systemic products, which in theory, would provide better control of the plant versus the use of a contact herbicide. And when we use herbicides in submersed situations, water exchange plays a role in limiting the contact time that s required for many of the systemic products to get the proper amount of uptake and translocation through the plant. We ve also had the opportunity to review some of the dewatered site application demonstrations up in the Pacific Northwest. And there seems to be a good bit of promise in being able to control the plant using systemic herbicides once the water s been removed and so that is driving this first phase of our field work with herbicides - to quantify the

15 Page 15 process of dewatered site applications and of course as far as depth of inundation, these schematics represent different water levels during the plant s growth cycle. If the plant just has its feet wet and most of the shoot vegetation is above the surface of the water, then emergent treatment should work fairly well because you ll get the contact time and translocation from the systemic products that you would need. Bbut as you increase water depth and there s a smaller percentage of the plant shoot mass above the waterline, the emergent applications are less likely to provide the kind of control you re looking for. Eventually, the tips of the plant shoots are the only portion above the water column and you may not get much translocation with an emergent application. Now, you re having to move into the realm of submerged applications where you re actually applying the herbicide directly to the water column. And of course in submersed treatments water exchange is probably the major culprit in most of the failures that occur - thus we don t get good control making a submersed application. And success is in many cases directly related to the size of the infestation you treat and the amount of untreated water that surrounds that plant stand. In small spot treatment scenarios water exchange is going to have more of an effect to dilute the herbicide than in larger - hundreds of acres of treatments at one time with a submersed application - and with water exchange the most obvious culprit is gravity flow. If you re in a riverine system or in a canal or a stream, water flow can dilute the product and move it off-target before it has time to have enough contact time on the target plant.

16 Page 16 You can have lunar tides, where water can move around, not too much of a problem in most of the U.S. where we treat large inland lakes such as the Corps projects around the country. Wind-induced water exchange is probably the biggest culprit where you have winds that can come-up and move the treated water away from targeted plant stands. You can also have water known as internal seiches or wind tides that can occur in large lakes and another problem can be caused by water temperature, where different layers of stratification can occur based on temperature. And you can have a situation where if the upper portion of the water column is warm and you don t get the herbicide down into the water column, it could get trapped in the warm water at the surface and then a wind could come along and move that water off so that it hasn t had a chance to mix and impact the targeted plants. Clearly, water exchange is a problem with submersed treatments. Our research approach for this work unit is going to focus on field evaluations with herbicides and we re going to build on the results of other studies that have been conducted and documented over the past few years. Some of those involve growth chamber, small concentration exposure time studies and some are field-scale situations. Also for our first effort we are focusing on Lake Pend Oreille which is a Corps of Engineers project in Northern Idaho. It s roughly a 100,000-acre reservoir and flowering rush invaded from Flathead Lake down the Flathead River down the Clark Fork River which enters the reservoir near the drift yard area and then it spread down the lake.

17 Page 17 The first reported colony of flowering rush was in This is a 2012 distribution map, a little bit dated - with the red areas indicating where the colonies of flowering rush have become established. And it s grown considerably since then. Our particular project this year on the dewatered site is in the area called the drift yard and you can see on the satellite photo it s an area t on the northern-northeastern shore of the lake. The Corps conducts a lake-wide drawdown that starts in early October and runs until about the end of April. This process is designed to de-water the littoral zone to create a 10-foot drop in water level. The annual drawdown is being conducted for fisheries management issues. So during most of the fall, winter and early spring, the drift yard area is going to look like this de-watered photo as well as other littoral shelves around the lake. You can see clumps of flowering rush rhizomes in this picture and the drawdown doesn t control the flowering rush because the rhizomes down in the mud and can survive the drawdown. When the lake is refilled in May - and for most of the summer - the littoral zones are reflooded, as depicted in the summer photo of the drift yard area - and you can see how the flowering rush is growing and making monoculture stands. Therefore, our trials will focus on treating the flowering rush during this drawdown period - before refilling of the reservoir. In this particular evaluation we evaluated five treatments with three reps each, and the treatment plots were a quarter of an acre each. Four of the treatments are herbicides and one is an untreated control (or reference). We selected imazapyr and imazamox as our primary herbicides based on some demonstrations that were conducted over the past couple of

18 Page 18 years in that general vicinity by Bonner County. We looked at those plots a couple of years ago, and the posttreatment results were very promising. So we decided to pick treatments that worked the best in the previous demonstrations and try to document those results with some numbers as our initial trials using imazapyr at three quarts per acre and imazamox at two quarters per acre. These are considered low treatment rates. Bonner County also noticed that with a little bit of 2,4-D added-in, they seemed to be getting longer-term control in those plots. So we evaluated some reps with one quart of 2,4-D added in to the tank mix with both imazapyr and imazamox. In addition, all the chemical treatments included a surfactant at one quart per acre. Now in order to conduct these studies - because there is a threatened species - the bull trout - that is in Lake Pend Oreille and uses the lake for migration corridors in the Clark Fork - Columbia watershed - we had to have a biological evaluation developed that was prepared by the Seattle District. And this BE was submitted to the U.S. Fish & Wildlife Service, which concurred with the finding that our treatments would not likely have an impact on the bull trout or critical bull trout habitat, so we were allowed to go forward with the project. We started that BE process a year before we actually were able to conduct the evaluations. But that s standard procedure for us whenever we re working in T&E waters, because of the federal nexus and certainly when we re working on federal lands or waters. In April of this year Dr. Madsen and the crew from the State of Idaho braved the final snowfall up on Lake Pend Oreille and laid-out our

19 Page 19 treatment plots. These are a quarter-acre in size and you can see we re in the drawdown condition at that time. Notice that there s a wooden boom-piling system to the east of the plots e which is actually is the drift yard" that collects the driftwood material that comes-in from the Clark Fork River, and you ll see that barrier system in some of the other photos. Our plots were laid-out in early April. Herbicides were applied prior to reflooding the 24th through the 28th of April. The temperatures had warmed-up and Bonner County - one of our partners - made the application with a spray boom and an ATV that was equipped with mud tracks so they could get across these flats and not bog down. This is when the plants - the flowering rush rhizomes as the shoots - are starting to emerge - about the time of treatment so they were an inch or two tall. The application was made evenly across these plots so that we achieved good coverage on the plants and the soil around the rhizomes. A schematic showing how the plots were laid out in the drift yard, and these represent the quarter-acre reps. This area around the plots and within the plots was pretty much a monoculture of flowering rush and the plots were randomly laid-out so that you - for example - there s an imazomaox plot shown in green. There s another imazomox rep here, another one up here and you can see our reference plots spread through the area. So this depicts the plot layout and treatment scheme. The county went in with the ATV and made even passes across each plot - a process to apply the proper amount of herbicide in a calibrated manner.

20 Page 20 When I show you some of the photos of the plots, you ll probably be able to see some of these untreated buffer areas in-between the plots that still have flowering rush occurring in them and in areas surrounding the plots. These plots were laid-out fairly close together because the preliminary work that we did and the observations that were made from the demonstrations the previous two years showed that we were not getting any type of movement of the herbicides through the sediment that would cross-contaminate the plots - after they were treated - so we were able to put them in a fairly tight area. We are assessing biomass to get an evaluation of treatment effects and this is a photo of Dr. Madsen doing the pretreatment after he laid the plots out in early April. We came back at 12 weeks post-treatment and you can see that the area hass been inundated by the water now. By July - here s the boom/piling barrier - and you can see all of the driftwood material that has been caught as it comes down the Clark Fork River. You can see a few scattered patches of flowering rush in this picture, and the water s about four to six feet deep at this point. We will come back at 52 weeks post-treatment (one year from treatment) to do the final assessment. What I m going to show you next are preliminary results of the application at 12 weeks post treatment. This photo is from the boat. You can see there s an untreated area of flowering rush and then you ll notice there are some areas that seem devoid of plant material. Little bit hard to see but this is a treatment zone right in this area. There s another one on the other side and you can see the untreated buffer strips in-between those plots where the plants weren t controlled.

21 Page 21 As you move out from the drift yard off that littoral shelf, you hit deeper water. Lake Pend Oreille is somewhere around 1500 feet deep, so it s one of the deepest lakes on the continent. Again this water is anywhere from three to 10 feet deep in these flats. This aerial photo that was taken at 16 weeks, a little hard to see because we had some wind, but here you can see the plots. There s one that s been treated. There s another one that s been treated with most of the plants removed. This would be an untreated reference plot - a dark shadowy area indicating healthy plants. There s another reference and again you can see the untreated buffer strips inbetween treated plots, and this is the drift yard area with the boom/piling system. At 12 weeks post treatment - when you sample biomass - this is what we were getting, mushy pieces of rhizomes with a few shoots that were surviving. That s at 12 weeks post-treatment. And then we floated through each one of the plots with four of us onboard taking visual estimates without comparing notes. Then John took those data and analyzed them to calculate a mean 12 weeks post estimated vegetation coverage in the each plot. In the reference plots we estimated there was a little over 60% cover, eyeballing from the surface again and you can see that our least amount of cover seems to be less than 15% as an average in the imazamox alone and imazapyr alone treatment plots. We did not get as good of control in the two plots that had the 2,4-D added at one quart per acre. However, I ll remind you that this is just 12 weeks

22 Page 22 posttreatment, and this is a visual estimation, so we ll have biomass to quantify and backup our visual estimates. So this is just an idea of what we saw on the site at 12 weeks posttreatment. Another picture from the boat on the edge of a plot you see flowering rush that has not been controlled and then here s the edge of that plot, pretty welldefined line between treated and untreated. When you get inside the plot you can see some flowering rush but the leaves are white and pink and they re still continuing to be affected by the herbicide treatment. In the meantime when the water came back up we got a nice flush of native pondweeds dominated by Richardson s pondweed. One of the objectives of evaluation is to selectively control the flowering rush to allow valuable native non-target vegetation to replace it and still maintain good habitat for fish and wildlife and water quality and so forth. So, those stands of pondweed looked good. There are other species mixed in there as well. So to summarize the benefits of the work, as John mentioned - phenological studies will benefit all types of management techniques. As far as chemical control - as we understand more about the life history we ll be able to develop application techniques that can provide improved control, evaluate different products that we might want to use at different times of the year - the timing of the applications. We believe that we will improve cost-effectiveness by linking those weak points in the flowering rush life cycle to the application parameters above so that we could use less herbicides. We aim to achieve consistent control and prolonged control and not have to do many repeated applications.

23 Page 23 Obviously we want to restore native vegetation that improves fish and wildlife habitat - and by the way - improve threatened and endangered species habitat and then ultimately we will be providing guidance to you folks in the field who are charged with managing these lakes and river systems and managing invasive plants. And finally I just want to throw a big thanks to our cooperators. These are some of the major cooperators on this particular work unit and study, particularly the Albany Falls Project on Lake Pend Oreille and Bonner County in the State of Idaho - but we ve had excellent cooperation with everyone in the area and everyone s very interested in what we re trying to accomplish. We recognize that the drawdown situation - while it seems to be very promising - certainly isn t one that occurs everywhere that flowering rush occurs so we ve still got a long way to go. But in the flowering rush situation, even in spot treatments- if you can get the bare ground or the bare sediment condition, I think we have a good chance of utilizing chemical control on that. And of course we re always seeking other sponsors and other cooperators to be part of the project. And that concludes the presentation. Courtney Chambers: Great, thank you very much Kurt. We re going to return to interactive mode. Operator: All participants are now in interactive talk mode. Courtney Chambers: At this time, we re going to open our line to questions. Remember to unmute your phone first so that we can hear you or you re welcome to submit a question through the chat box.

24 Page 24 Linda Nelson: Courtney, this is Linda Nelson and I have a question I can start-off with. Courtney Chambers: Great, thanks. What have you got, Linda? Linda Nelson: So Kurt and John, I know the data that you showed with the visual estimate of cover is just some preliminary data in that 12 weeks but, when I look at that I kind of wonder is there a possibility that there s antagonism when you add 24D with the Imazapyr and the Imazamox product? And, I was wondering if you could comment on that or is there any literature or data in the literature that would suggest perhaps 24D and these (Imazadilone) herbicides are possibly antagonistic when mixed together? Kurt Getsinger: Linda, that s a good question and I don t believe that the rate of one quart per acre of 2,4-D is a problem. It s a very low rate and the reason we added those to the tank mix is because Bonner County had evaluated similar plots in their demo two years before and I saw those plots with those rates applied - and at one and two years post-treatment, those plots showed excellent control. I didn t see any imazapyr or imazamox alone plots because Bonner County was adding 2,4-D to their products as an activator at a very low rate - and it s not uncommon to see that used on roadsides and other treatments with these imi-typeproducts. But it remains to be seen if control is improved with adding 2,4-D. Certainly at first look it does not look like we got the control using 2,4-D as an additive, as we re getting with those imazpyr and imazamox products alone. Over time, the numbers will bear that out and if it s not prudent to add the 2,4-D, then adding 2,4-D would not be part of the recommendations and field guidance.

25 Page 25 John Madsen: Okay, can I add something? Kurt Getsinger: Yes. John Madsen: So in forestry it s not uncommon for applicators there to also mix Imazapyr with 24D and my former colleagues in forestry there at Mississippi State University say that the chemicals mixed with no problems but there are little benefits resulting from adding 24D to the Imazapyr so I think this is kind of a case where we re doing a trial that includes a commonly-performed mixture. But coming into it I don t think either Kurt or I had a lot of confidence that adding 24D to Imazapyr was going to make much of a difference in the amount of control you got. Kurt Getsinger: And Linda if we can show that quantitatively then that might change how some of the treatments are being conducted up there now with adding 2,4-D in. If it looks like it s not needed, then you can drop that from your treatment plan. Without that data, those things become embedded in the culture. Linda Nelson: No, I totally understand, thank you. Kurt Getsinger: And Bonner County, has been a key cooperator and we felt that this would be a nod to them to quantify what they ve been doing and see if it makes a difference - so that was part of our approach as well. Courtney Chambers: Very good, thanks guys. Anyone else have a question for Kurt or John? (Damian Walter): Yes, (Damian Walter), (Walla Walla) district.

26 Page 26 (Damian Walter): I have a question in Walla Walla District. I ve seen some other presentations where they talk about flowering rush declining in Europe but nothing is really known or I haven t gotten anything as to any research that s being done to find out why it s declining there. Is that a possible tool for us over here? Is it something ecologically just over there? Do you have any information on that? John Madsen: This is John, no, not really. You know, I m kind of peripherally involved with the biocontrol. I think actually (Jennifer) s more involved than I am and I know that they re doing some work over there but that s a case where the flowering rush is a native and is actually somewhat rarer. It s hard to find flowering rush populations and to find insects that are on them. I think since the plants that we re having in the western part of the U.S. are triploid, they are clearly a variety that was devolved for horticulture and horticulture, you know, often not on purpose but they often will take a triploid because it grows more vigorously and it flowers more beautifully and it seems more resistant to problems. So the plants in Europe are the native diploid. They may not grow as well, that the triploid plants that we have here have that added, you know, vigor from being triploid and being selected as a horticultural strain. So often the plants we see in the wild are from horticulture and they re some selected variety that escapes cultivation but I hope that kind of answers the question in a way. (Damian Walter): Yes, kind of does, yes.

27 Page 27 Kurt Getsinger: One thing I wanted to add-in on that John - is that certainly plant populations shift and they wax and wane - be due to short-term or long-term climate change or other events. But this reminds me a little bit of what occurred back in the U.S. when Eurasian watermilfoil got established in the Great Lakes, in Wisconsin, Minnesota, Michigan and there were some fairly significant declines of milfoil that occurred in the late 70s and early 80s. As far as anyone could tell, those populations were not declining because of any active management. And so there was a line of thought back then that said they re going to grow - explode - for 15 or 20 years and then fade away but that actually did not happen. The nuisance levels of milfoil are back and they ve been back for many years. There was a short-term decline of some sort, but no one could ever pinpoint what caused it, if it was suppression from some insects, some people thought maybe it was a pathogen, a virus. Madsen that was probably going on about the time you were in graduate school back in those days so we have to be a little bit careful when you see something declining. It doesn t necessarily mean it s going to be a permanent thing. Courtney Chambers: Very good, okay, we have just a couple of more minutes if there are any final questions. (Jeffrey Pettingill): I have - this is (Jeffrey Pettingill), (Bonneville County), can I ask a question? Courtney Chambers: You bet, yes.

28 Page 28 (Jeffrey Pettingill): Thank you. Kurt and John, John I know you were going to make it out here to kind of look at this gem-like process that we have with flowering rush in the irrigation system. We re going to take divers back down next week and go after that small patch in the lake but we tried to a similar thing that Dr. Getsinger was looking at that (Brad Bloomer) s been doing at Bonner Lake in an irrigation canal last fall. We went in there as soon as we could after it watered-out like two days and we put in the imazapyr. We also tried imazapic mixed with imazapyr and the triclopyr and all that and we had absolute failure so I know that Bonner County s had success because they could do it in the spring right before the storm. So my question for you both of you we re talking to (Tom Wolfe), we re looking at maybe trying to do some diquat because I know it has a Section 24 to utilize diquat in irrigation system. This is a very small nine-mile irrigation system that goes through Ag lands and then through a small community. What do you guys think about taking the Imazapic and mixing it with the diquat and then going down through there? Kurt Getsinger: Is this a submersed application or after you ve dewatered? (Jeffrey Pettingill): This will be immersed above the water, half of it is and then the other half of the plant is obviously because of the rhizome it starts at the banks and then you can literally just look at the rhizomes working its way back across the irrigation system. It s only about foot wide, it s pretty small so it s going to be a combination of both but it will not be after dewatering because we learned our

29 Page 29 lesson. We can t do it in the spring because of the number of days needed before you can utilize that irrigation water again. Kurt Getsinger: Yes. I have actually not worked with imazapic. John, have you had any experience with those combinations? John Madsen: I haven t worked with Imazapic because I m not aware of an aquatic label but I do know that 2,4-D can be antagonistic with some of the systemic herbicides. We did some work with 2,4-D and I think it was imazapyr and I know we did it with (wypitie oxlam) and it was actually antagonistic. (Jeffrey Pettingill): All right now John I m thinking of Clearcast. Is that imazamox? John Madsen: That s imazamox. Kurt Getsinger: It s imazamox, yes. (Jeffrey Pettingill): Okay, imazamox, I m sorry, not imazapic but imazamox. John Madsen: You know, in theory, you know, if you re using a quick-acting contact in combination with a slower-acting systemic... (Jeffrey Pettingill): It would be antagonistic. John Madsen:...well, not just antagonistic but you may shot that plant down before it has a chance to translocate... (Jeffrey Pettingill): Right.

30 Page 30 John Madsen:...Imazamox but it s something we could look at and maybe if you want to send offline send me an , I ll look into it and see if I can come-up with some answers for you on it. (Jeffrey Pettingill): Well, we re going to play with it a little bit either way. John Madsen: At this point some of those trials I think anything people are looking and doing as long as it s legal, probably have some value and we may hit on something rather than trying to say no, it s not going to work. (Jeffrey Pettingill): Right, but I was just thinking about the combination because I need one to be above the water and one to be below the water. Maybe we can do something. I was just curious if you guys have tried anything with that combination so thank you. John Madsen: Yes, I ve done some work with diquat by itself as a submersed application and had some success and then I know that the manufacturer or whatever you want to call them of Imazamox has done a lot of trials with Imazamox as applying to the emergent portion of the plant and, you know, the pictures look good but I haven t seen any data. (Jeffrey Pettingill): Well, okay. Courtney Chambers: All right, well with that guys we are at the end of our time - our scheduled time here - Kurt and John do you all have any final comment for us today? Kurt Getsinger: My final comment would be if any of you - and some of you already do this - but as you conduct trials or studies or have some information available that might be useful to us or other folks, we d be glad to talk with you or take a

31 Page 31 look at some of your data, - to get some ideas about what we need to do and are we seeing or are we missing some things we need to be looking at? Our next phase will be to start trying to tackle these submersed applications which are going to be tougher to do. Courtney Chambers: Very good. Anything else from you John? John Madsen: No, I appreciate you all listening to our presentation. Thank you. Courtney Chambers: Yes, well we re grateful for both of you sharing today and thank you participants for tuning-in. Please watch your for announcements for our upcoming meetings. We do have one scheduled for let s see (Julie), can you help me out? We do have a future Webinar scheduled for... (Julie Marcy): One on the 14th of October Courtney on Avian Vacuolar Myelinopathy with Dr. (Susan Wilde). Courtney Chambers: That s right so the 14th of October, if you want to mark your schedules. Be watching for Outlook invitations and we would love to have you join us again. I hope you all have a wonderful afternoon. John Madsen: Thank you. Kurt Getsinger: Thanks. END