2015 Wisconsin Plant Disease Update  - We're gonna welcome Anette Phibbs from DATCP. Right now, she's gonna give us an update from the 2015 Wisconsin crop diseases. And she has a Bachelor's Degree and Master's Degree in Botany from the University of Wurzburg Germany. She's been working for DATCP since 1992. Right now, she is currently the director of the plant industry laboratory and her job is to diagnose plant diseases and nematodes on agricultural crops and ornamental's grown in Wisconsin. So, welcome Anette.  - Thank you, thank you for the nice introduction and I'd like to ask you to please hold your questions and fire til I'm done with my talk, since we're being taped. No pressure.  Today, I'll be talking about our survey results from last year. And if I'm going a little too fast or you wanna revisit some of these things, we have a website called pestsurveywisconsin.gov and there is a lot of reports on there and you can read it all at your leisure later. 

 So, I'd like to focus on a number, a couple of groups of pathogens that we encounter during the year. We're looking mostly for exotic and new things and new things is sort of loosely within the last 10 years still pretty new to us. One of those groups are the Phytophthora's or the omi seeds of soybeans, soybean viruses, corn diseases, and then we'll look ahead a little of what we might do next year.  The Phytophthora subspecies or Phytophthora,  the omi seeds are water malts on soybeans. These are the organisms that are sort of like fungi, but not quite. There are many different species of them. We've been looking for a number of years to identify how many species we have in Wisconsin. Often, they also occur in combination with Pythium, which is a closely related group. And this is an image of a sample that we took a couple of years ago. Where you can see the fine roots and the tap roots affected by both a Phytophthora and a Pythium, which you often find them in combination. 

 The Phytophthora sojae is the one we're used to. It's more common in Wisconsin. All the red cross hatches, those are the counties we found this particular pathogen in in 2015. Every year, we sample about 15 soybean fields in the vegetative growth stages and that takes place early in the year in June. But, Phytophthora sojae can affect any life stage. It can cause seed rot, pre or post emergence damping off stem lesions in the reproductive stages. And then you also have rotting lateral and tap roots and it causes very characteristic shock led color lesions on the stem. But, we're finding more and more Phytophthora and I wanna talk to you a little bit about those. As I said, we've been doing this survey for a number of years. We started in 2008, looking for Phytophthora sojae. 

 When I say we're looking for them, we're using methods that are based on genetic material. It's very difficult to identify these organisms just by morphology under the microscope. So, we've been fortunate to have these methods available now and you can see that over the years, we've had quite a bit of Phytophthora sojae, those are the blue bars.  Last year 49%, this year, I should say in 2014, it was 49%, in 2015, 38%. So, it's still a lot of Phytophthora sojae. When we started looking for Pythium, we realized, well pythium is just about everywhere and all the time. So, there's a lot of pythium and there's a lot of pythium species. And we tried to speciate them, but that's still a lot more work that needs to be done there. In 2012, we found a new species, Phytophthora sansomeana, 2014 and 15, we found two new species each year. So, I'll be talking a little bit about those. 

This is just an overview map of where we all found these species in soybeans.  You can look at this at your leisure later, but there's a lot of different species and the take home point is that we have more than just P. Sojae now, we probably need to realize that Phytophthora sansomeana is a player in the disease component. The other new species, we're not so sure that Phytophthora pini, Phytophthora species personii, that is so new that it doesn't even have an official name yet. Phytophthora inundata, and Phthopthora iranica are also very new and we don't know a lot of these, a lot about these newer finds.  Just to talk a little more about Phytophthora sansomeana, the interesting thing about that is that it has multiple hosts, P. Sojae's only on soybeans, but sansomeana is also on corn, and on wheat and alfalfa fields. And we also found it during a totally unrelated survey on Christmas trees and AB's or noble firs, that's Balsam, Fraser, and Douglas fir. And it does a really bad number on those trees as you can see.  So we combined the data from those two surveys and we really can find it in quite a few areas of the state now, in 15 counties. So, that's a lot of counties that have it present. Now it's not in every field, but it's certainly widely distributed. 

 Some of the newer things are quite exciting to look at under the microscope, as you can see. Sort of like a space station, it looks like. So, these are really fun to look at, but you need the genetic testing to actually identify them. The reason I grow them out, and I'm showing you this pictures is because well the pictures are much nicer than a picture of a pi pattern on the tubes, boring. And also, I grow them out because I want to share them with researchers that can use them in their research to find out more about them. So this particular one, we found this year in Buffalo county. And it's really known to affect hardwood trees, shrubs, and not so much soybeans.  That's a new one.  But, a lot of these new species that we find, have in common that they are on wet and flooded soils.  The finds that I have are homologous with finds from Europe and South America. 

That doesn't mean they're brand new here, we have new methods, and they may have been here for a while, but it's sort of an affect of having new tools. There's a lot more we need to learn about them. But, a lot of what these new one's have in common, that they like flooded soils, and they thrive in these flooded soils. So when we have flooding in soybeans and wet years, that might be a reason we've started to find them. Another commonality of these new species, is that they're always and often in combination with Phytophthora sojae or phthopthera sansomeana. So, that might indicate that there more opportunists. We really don't know that. The Phytophthora irranica has been known since 71 from Iran.  And we found it in Lafayette county in 2015. And those hosts are eggplant, potato, tomato, and sugar beets. 

The more solanaceous crops.  There's a lot of research going on on this group of fungi. So, it's an explosion of taxonomy and species. The next one that we found, last years actually, interesting also for our nursery growers because it causes a lot of issues with rhododendron production, I find it particularly on nursery stock that's imported from other states. The old name was plurivora citricola. So, for some of you Phytophorologist's, you might recognize those names. It also survives and actually thrives really well in reservoirs and rivers. So, if you're irrigating from rivers and ponds that's a thought you should have to be cautious because you might be introducing more than water when you do that. This one was found in Eau Claire together with sansomeana  And, the last one in Winnebago county from 2014, personii, we don't know any of the hosts. There's only been two reports in the US and originally it was found in Australia. 

 So, as I said, I collect these things and I send them to Damon Smith at the UW and many other people's collections so they can study them further and find out which one we really have to look out for. Let's switch to soybean viruses a little bit. We've been doing a survey on soybeans during the summer in combination with soybean aphid surveys since 2003. Actually before that, I think, but in 2003, we found soybean dwarf virus. I've been tracking that for a number of years and there's actually, if you can see, sort of the red bars, you see an increase in detection's over the years. Soybean Vain Necrosis virus made a big splash in 2012. It was an new discovery. 2013, we still find a lot, and now it's slowed down a little bit. We also look for a alfalfa mosaic virus, it's kind of the old standby something that seed and aphid transmitted. And what we've seen over the years A little uptick last year on that one too. 

And this is a map of where we found these different viruses in the state. It's basically where soybeans are grown. Six or 12 percent of the fields were infected with alfalfa mosaic virus, soybean dwarf virus 12%, soybean necrosis virus, 6%, so that's significantly down. And to understand soybean vain necrosis virus, we need to know that it's a tospovirus transmitted by thrips. And the thrips count was down this year too. So, if you have no thrips, you have less virus because there is no thrips to transmit the virus. It was first detected in Tennessee in 2008 and it was our most common virus in 2012 and 13. So, it's interesting to see how these populations ebb and flow. And in the field, this is one that's pretty easy to ID or at least to spot because it has these brown, necrotic lesions along the veins, and yellowing.  So, its something to look out for. 

Soybean dwarf virus, as I said, we found in 2003. We know that there's a reservoir in Clover, so they probably come from there. It's a problem in Japan, but it never has any significant effect in Wisconsin, as far as we know. It is transmitted by the soybean aphids, which are persistently feeding aphids, and we know that in Wisconsin we have dwarfing strain and yellowing strain, but mostly dwarfing strain. There's actually very complicated story of different strains of this virus on different hosts. There are up to 50 hosts. But, I think our soybeans may not be as susceptible, so, so far, no problem with that. Shift gears a little bit to soybean diseases, Asian soybean rust was also not detected in Wisconsin. We do a lot of that. We look for exotic stuff and then we're happy when we don't find it. 

So, this one, we didn't find in Wisconsin. But, it made it as far north as central Illinois, but by that time, it was November, so it's really not a big deal at that point anymore. And, it spread throughout the United States. About 10 states were affected. There's a list there and there's also IPM Pipeline website where you can track this. There is a few look-a-like of species or pathogens on soybeans, like septaria, a brown spot, so if you see something suspicious, please submit to an extension office or UW to have it checked out. Another one we want to keep tabs on is Frogeye leaf spot, that we know goes back to at least 2000, when we had a lot of fields infected. But, in the last couple years, we really haven't seen it. But at leaves, it was nice, well frogeye leaf, frogeye shaped spots on the leafs. So that's also something you can spot fairly easily in the field. 

 And on to corn diseases.  We inspect corn for a Fida sanitary certification so, this is a service that DATCP offers.  In 2015, we inspected 53 counties, 53 fields in six counties. 39 fields, that's not a huge number, that's a lot of corn in Wisconsin, you know that. So this is kind of a spot check  of what goes on and we take those samples and we test it for everything just to see what might be out there. We haven found steward's wilt since 2010, which is really good. That's a regulatory concern, although it's mostly deregulated now. Canada doesn't check for it anymore. Goss's wilt was up this year. It's a little bit skewed. 

I wouldn't put too much emphasis on those numbers because of how biased the survey is based on what inspection needs require. But, we found it in Adams, Dane, Eau Claire, and Rock counties. So that's four counties. And it's been more frequent since 2010. So, those are two bacterial disease that are sometimes a little hard to ID. We check for some viruses too. Maize Chlorotic Mottle Virus, that was one that was of concern, in combination with podi virus can cause a serious disease. It's in South America, Hawaii, not in Wisconsin. So those are the kind of exotic things we look for. No High Plains Virus either. 

We find a few of the Maize Dwarf Mosaic Virus, now we call it Sugarcane mosaic virus and those are usually from the same spots. So, there are some lines that are infected. In terms of the real fungal diseases, gray leaf spot was at 18% of the samples I examined, northern corn leaf blight in 60% of the samples. It's always really common, but that was quite a bit. And then, Very Common common rust, aptly named. There's a lot of that and I checked every sample to make sure it's not southern rust and I didn't see any southern rust. It may be out there, but we didn't find it.  If you have any inspection needs for seed field inspections, those are done during the growing season, please contact Ellen Natzke at the office or check out our website. We do inspections on, not just corn, but beans, onions, pepper, tomato, soybean, anything you can grow in Wisconsin, we'll check.  And, just looking ahead a bit, what are we gonna do in 2016... 

 going back to 2015, our neighbor states Illinois and Indiana found tar spot on corn, that was fairly exciting, a new disease on corn. We didn't see it on our inspections or during the pest survey, but it might be out there. So, we're gonna look for that again next year. We're also in the process of doing a survey for serial cyst nematodes on corn and wheat for exotic nematodes. So, we'll be reporting on that next year. And, with that, I'll thank you. And I'd like to acknowledge my collaborators in the lab, Susan Lueloff and in the field Adrian Barta. And all our skilled professionals that bring in the samples and keep an eye out. And our funding agency the USDA aphis and DATCP. (crowd clapping)