2015 Wisconsin Plant Insect Update  Our next speaker today is Krista Hamilton. Krista is an entomologist with the Plant Industry Bureau at DATCP. She has directed and continues to direct an exceptionally-productive state-wide pest-insect survey program. She's been doing that for the last 17 years. Hard to believe 'cause I think I remember pretty well when she started. She's the primary author of the Pest Bulletin, which if you guys are not receiving it, I would encourage you to make sure that you go to her web site and sign up for it. It's a very informative insect entomology piece that she puts out during the summer months when insects are active. Krista's originally from Wausau, Wisconsin. She now lives in La Crosse. She holds a bachelor's and a master's degree from the University of Wisconsin in entomology. 

Please welcome Krista Hamilton. (applause)  - Thank you. Thank you very much. So this morning we'll be taking a look at the results of Datcp's insect surveys from last season and what they can tell us about potential crop-pest pressure in 2016. Most of the surveys are ones that the department has conducted for a long time. Our European Corn Borer Survey, for example, is nearly three-quarters of a century old. Our rootworm surveys started back in the early 1970s. So my point in telling you this is that we have extensive data sets on these insects. And when we compare 2015's results to those long-term records, it's apparent that levels of all but one of these pests are exceptionally low, and in some cases historcially low, so you'll be seeing some low numbers in the next 20 minutes or so.  To begin, I just wanna take a minute to provide some background on the Wisconsin Pest Survey Program. 

So we're the group that's responsible for the survey results you'll be seeing. We've been around 100 years, tracking pest populations and documenting growing-season trends through our surveys. One of the main points of this work is just simply to help Wisconsin growers anticipate pest problems so that they can take measures to avoid losses.  Another important objective of the work is exotic pest detection. So we conduct surveys to detect new or exotic pests as they show up in the state. Some of our survey work also supports the process of export certification by confirming presence or absence of certain regulated pests. So those are the main objectives of our work. We sample thousands of fields across the state each summer and we cover all the major agronomic crops as well as specialty crops, so everything from wheat and corn to apples and grapes. And in addition to our own surveys we also receive information from networks of cooperators around the state who send us insect counts on a regular basis. And I think most of you are probably familiar with that. 

Some of you are our cooperators or have been at one point. And the help of our cooperators is really vital to our program. So in short, we collect a lot of information through the program each year and we've been around a long time.  Here's where we publish our survey results. This is the Wisconsin Pest Bulletin. It's our weekly newsletter. It's published each Thursday from April through August during the growing season. And it's a compilation of topics. It includes things like insect growing-degree days, alerts to new pest finds, and a diversity of observations from our surveyors and from growers around the state on different pests. If you're not a subscriber, please go to our Web site and sign up. 

I know that a lot of consultants consider this a really useful and timely resource.  So these are the insects that we'll be focusing on today. We'll start with our corn-pest surveys and then I'll conclude with just some brief notes on a newly-established pest in the state, the brown marmorated stink bug. So we'll get started with the result of the European Corn Borer Survey. As I mentioned, this is the oldest of all of our surveys. It dates back to 1942, when the corn borer was still an exotic pest, brand new to the state. The survey objective has always been the same. We're sampling corn fields in September and October to determine the size of the fall population of corn-borer larvae. So these larvae will overwinter in cornstalks, much like you see at the stage here. They'll pupate in spring and then begin emerging as moths in May and June. 

So that fall population is really our best predictor of the size of the spring moth flight. And in years when corn-borer populations fluctuated a lot more than they do now, this was really a key predictive survey. At this point you know the corn-borer population has collapsed in the last 15 years or so. So I think what our survey helps to document at this point is just really a continued low population trend.  So this map shows the 229 sites that were surveyed for corn borers last fall. What you'll notice immediately are a lot of black circles. So these circles are negative sites where we found no larvae or no signs of corn-borer infestation: things like broken stalks or tunneling in the stalks. That was 86% of our survey sites. The green circles represent sites where we found 0.01 to 0.5 borers per plant, so low counts that are less than half of threshold. The yellow circles are where we found moderate counts in the range of 0.51 to 0.99 borers per plant. 

And then the one orange circle you can see over in Winnebago County is the only site where we found an economic population above one borers per plant.  The 2015 state average was just 0.02 larvae per plant. That's two caterpillars per 100 cornstalks. It's the lowest average we've documented in the history of Wisconsin Corn Borer Surveys.  What should be obvious is just corn borer was very very scarce again in 2015.  When we look at the district averages, I think what you'll see right away are just a lot of zeros. Again, these numbers are really low. All of our nine districts had averages of 0.04 borer per plant or lower, so four larvae per 100 stalks. These are low numbers. We did see some increases in five of the nine districts, but these were very minor insignificant increases. 

And I'll just say it again, these are some of the lowest averages that we've seen in 74 years.  So for 2016, what those results suggest is that populations are still historically low. I don't think they're likely to change anytime soon. To date there's been no evidence of corn borer resistance to BT or any BT trait. So that's good news. I think that extremely-low larval population that we saw in fall should produce a really small flight of moths next spring, and in a small subsequent first generation of larvae. So a favorable forecast for 2016.  Next up is the corn rootworm beetle. So this survey takes place from mid to late August, and it's timed to coincide with peak beetle emergence. So we go out into the cornfields once 50% or more of the population has emerged. 

And the idea is that we're surveying cornfields to get a snapshot of beetle populations, which in turn are a predictor of larval root damage potential in next season's corn.  So the reasoning is that high beetle numbers would lead to high egg populations in the soil that hatch in the spring and then become damaging larval populations. So it's just a way to forecast the risk of root damage from year to year and to evaluate beetle pressure.  The 2015 Rootworm Survey found a state average of 0.6 beetles per plant. That's an increase from 2014's very low average of 0.4 beetles per plant; yet it's still below both that 10-year average and the threshold. If you look at the map, again, the black circles are negative sites where we found no beetles; the green circles are sites where we found low counts of 0.1 to 0.4 beetles per plant; the yellow circles are where we found moderate counts: 0.5 to 0.7 beetles per plant; and then orange circles are, again, the economic populations above 0.8 beetles per plant. And remember that what's considered the threshold is 0.75 beetles per plant or about seven to eight beetles per 10 plants. 25% of our sites had economic counts last year. That was an increase from 2014 from 16%. But again, that was a really low-beetle year. 

So 25% is about average. It's what we often see.  So when we look at the district averages, I think it's more clear where those increases occurred. The first thing I would point out is just that populations increased in the eastern two-thirds of the state, so these six crop districts. Of those six districts, the largest increases were in the south-central area and in the east-central area where those average counts rose from 0.3 to 0.8 beetles per plant, so they more than doubled. We also saw moderate increases in the Southeast, Central, and North-Central Districts. By contrast, in the western part of the state we saw decreases in all three districts. Except I would point out that in the southwest this average of 0.8 beetles per plant is still considered high. So what this suggests is that rootworm pressure in 2016 should be greatest along those southern three tiers of districts, so that's no surprise, but also in the east-central area. And then when we look at the rest of the state, rootworm pressure is really pretty low, those averages are quite low. 

 So again, the higher numbers that we saw last season do suggest we'll see increased rootworm pressure in 2016, but not statewide. There's definitely some key areas where we're expecting higher numbers of beetles and potentially root damage; and that would be those southern three districts and the east-central area. And Brian Jensen's gonna be up next talking about rootworm resistance management recommendations so I'm just gonna keep my notes here brief. I think the three key things to remember about rootworms and their management is that crop rotation is still an effective management strategy and it's the simplest one, it's I think one that everybody should consider; especially if you're seeing rootworm problems. Also, rotating traits is really important. Avoid using the same trait or the same product year after year; otherwise you're selecting for resistance. And then lastly, scouting is just so critical. It's not that hard to do. It takes once or twice going out in late August or September. And there's really no substitute for knowing what pressure is like in those fields, scouting is imperative. 

 So now we'll move on to the result of the Western Bean Cutworm Survey. The western bean cutworm, as you probably know, is a pest of corn and dry beans. And it first started becoming more prevalent in the state about 13 or 14 years ago. We began monitoring the adult flight, and there's just one flight per year, back in 2005, and we've seen some really I think dramatic change in the last 11 years.  So our survey consisted of 96 traps. So each one of these circles represents a pheromone trap. And in those traps, during our 10-week monitoring period, which was from mid-June to mid-August, we caught a total of 644 moths, or seven per trap. That was an increase from 2014's very low count, but very very low in comparison to the survey record documented back in 2010.  In looking at the map, there's a lot of green circles. Most of our traps caught fewer than 25 moths during this 10-week monitoring period, so really low numbers. 

The highest trap count was just 112 moths at a site in Columbia County. So although the annual flight was larger than 2014's flight, it was still comparatively small. These are low numbers.  Here we have the last six years of survey results. And the bold orange number at the top of the maps represents the state total moth count for the year, so that's the cumulative count. So from 2005 to 2010 the trend that we were seeing was an almost doubling of that count every year. And then the number peaked in 2010 at almost 11,000 moths. Since then, you can see that populations have declined dramatically; in fact, they've really plummeted in the last three years. So we've now seen three years in a row of really low western bean cutworm moth counts.  And I think this is encouraging news for 2016. 

Just six years ago it looked like this thing could potentially be a really serious threat to corn production in the state, potentially replacing corn borer as one of our major caterpillar threats. And now it seems like it's probably only going to be a sporadic pest, at least for now. Nevertheless I think it's still important if you are in the central area of the state where we tend to see higher populations, or if you work with clients who've had issues with this pest, think it's still important to scout for those egg masses and small larvae as soon as corn reaches the late boil stage. And then the last reminder is just to know your BT hybrid and how it should perform. They don't all perform equally well against this pest. Some perform only moderately well; some have no effectiveness. So just make sure that if you have a BT trait that's supposed to have efficacy against this pest that it's doing what it should.  All right, so that completes our corn pest surveys, so I'll talk just a few minutes about soybean aphid. Our surveys for soybean aphid begin just as soon after soybeans emerge in spring. And typically we see our first aphids around the first week of June. 

This year it was June first. We then wait usually four to six weeks for aphids to colonize more fields and for populations to increase, and then we go in and sample in two intervals, usually the first from mid to late July and then the second in August. And the idea is that we want to see how those populations change over the course of two to three weeks and we really wanna be in those fields as population densities are peaking. We wanna know what those numbers look like. And sometimes if we only survey those fields once, we kind of miss that window.  Here's what numbers looked like in July. So we surveyed 108 fields, this was during the last week of the month and into August, and found a state average of only 15 aphids per plant, so that's very low. 85% of our sites had fewer than 25 aphids per plant. There were just four that had moderate averages of 101 to 249 aphids per plant, and no sites with economic populations above the 250-aphid-per-plant threshold. So what we found was that aphids colonized fields very slowly last season and populations grew very gradually and really remained low throughout July. 

 When we resampled those same fields in August we found slightly higher densities. That state average density increased to 35 aphids per plant, so it doubled, but it's still a very low average. We had a handful of sites that had moderate populations in that range of 101 to 249 aphids per plant. Just one site had an economic population. So what these results suggest is that most soybean fields did not develop high populations last year and most did not require treatment, although there were definitely definitely exceptions. So I think we could call 2015 probably a low to moderate aphid year.  For 2016, the aphid outlook is a little bit uncertain. I think we never know quite what to expect of the soybean aphid. If it follows this every-other-year cycle with populations being lower in even-numbered years then we're potentially looking at lower densities. Another factor that we should consider are those multicolored Asian lady beetles that were everywhere last fall. 

So remember, these things are the number-one aphid predator, and last fall's numbers were really some of the highest in a long time. So all those beetles, while they were sort of a short-term nuisance, could have a longer-term benefit in terms of lowering aphid numbers for 2016.  And then lastly I just want to make you aware that the brown marmorated stink bug is now considered established in Wisconsin. I know most of you are probably familiar with this pest. It's been on our radar for about a decade. This is another exotic Asian insect that's invaded the state.  It was first confirmed in Wisconsin back in 2010. And I guess in the five years following, from 2010 to 2014, there were 18 confirmed reports. Last year there were 35 confirmed reports; so almost double the number in the previous five years combined. Most of those cases were in Dane County in the Madison area. 

Some of the reports were also from Brown County and Milwaukee County. So what we think, or feel certain about, is that it's established in Dane County, possibly in the southeast or eastern areas of the state as well. I think what's important to know is that the trend with this stinkbug is that it tends to start causing crop damage or moving into crops three to five years after that initial detection. So what that means is we could potentially start seeing this thing in crops next year; especially after this mild winter. Soybeans and sweetcorn are both considered high-risk crops.  So this map just shows the current status of the stinkbug. It's been detected in 42 states and two Canadian provinces.  It's considered a fall nuisance pest in 17 states. And it's considered a severe agricultural pest in nine states, so all those red mid-Atlantic states that you see. So I think it's just a matter of time before we become a yellow state and then a red state, so I think it's really important to be on the lookout for this insect. 

And as PJ just mentioned in his talk, it's critical if you think you see this thing, take a sample and get it to the Insect Diagnostic Lab at UW because that's really the only way we can confirm whether or not it's indeed the brown marmorated stinkbug. And then I would also point you to that StopBMSB.org web site.  All these states that have serious problems with this pest are doing a lot of great research, and so there's a lot of good information on how to manage this thing in field crops. So please take a look at that Web site. It might give you some good ideas on what to do about this thing if it does show up next season.  So that completes our review of the 2015 Insect Surveys. I think with the exception of maybe the corn rootworm beetle and this new stinkbug it's a pretty favorable forecast for 2016.  We're looking at some really low insect populations heading into the next season. Just a reminder, please sign up for the bulletin if you haven't already done that. And then I just wanna say thank you so much to everybody who contributed their time and their energy to this program last year; especially during the busiest time of the season. 

The survey results that you've just seen are really made possible by the people who have helped out our program, so thank you very much.  (applause)