(Jim) Good morning folks. Welcome to That’s My Farm. I’m Jim Shroyer, your host. And we’re in luck because we’re on the agronomy farm and we’re gonna be talking about corn disease and soybean diseases with Dr. Doug Jardine, our Extension Plant Pathologist. So now is the time to get a refill on that cup of coffee. Hurry on back and we’ll start the show. See you then.Closed Captioning Brought to you by the Kansas Soybean Commission. The Soybean Checkoff, Progress Powered by Kansas Farmers.
(Jim) Good morning folks, welcome to That’s My Farm. I’m Jim Shroyer, your host. And we’re in luck because today we’re on the agronomy farm on the campus of K-State and also we have Dr. Doug Jardine our Extension Plant Pathologist for Row Crops. And Doug, thanks for being on the show first thing. This has been a really weird year with being dry early, wet early, you know in the corn planting time and bean planting, sorghum. And I’m guessing that this has kind of set up for all sorts of problems with diseases. So, give us kind of a general overview of diseases so far for the state. (Doug) OK. We’re talking about large amounts of rainfall at planting time. There’s a couple of different things that we can be dealing with. One is in corn; most corn comes treated with fungicide. It will actually tolerate pretty harsh germination conditions. But if it gets wet enough, long enough, those seed treatment materials will tend to deteriorate, and then we can start to get some stand loss. And so we had that. And of course in many places they just flooded out so there’s not much… (Jim) And erratic emergence like we had here behind us. (Doug) And that’s probably where some of those plants may have been lost from the seed treatments. Same thing holds true with soybeans. We got a very important disease called pythium out there. Seed treatment, or soybeans doesn’t come with a seed treatment unless the producer orders it on there. And fortunately now days probably better than 75 percent of people are using a seed treatment. So that helps a lot. (Jim) Protects against these kinds of situations. (Doug) It protects… (Jim) A lot of times it wouldn’t matter, but in these situations like we had this year… (Doug) Right. It protects against the diseases that are in the soil that like it kinda cool and wet. And so, those producers that used the seed treatment this year, they’re probably relatively happy with their emergence stand counts. Those who didn’t, are probably wishing they did. The other thing about the wet soils is there are some diseases that the infection period occurs early in the season when it’s wet, but then the disease kind of lays dormant in the plant and then if we get the right conditions later on in the season then we have problems. The two most important ones of those are actually in soybeans. We have the Soybean Sudden Death Syndrome; it infects early, not much going on, right this time of year. But if we start getting some significant rains or under irrigation in late July or August, then we’ll see that disease start to bloom if you will. The other disease is just actually the opposite, and that’s charcoal rot. Charcoal rot likes it wet early in the season for that initial infection and then it just kind of lays in wait in the plant, and if it gets hot and dry in late July or August which… (Jim) Which it always seems to do. (Doug) It’s often the case in Kansas. Then we’ll start to see that disease blooming. And charcoal rot to the average farmer is going to look like they’re just dying from drought, but the organism is helping them along a couple of weeks earlier than what would otherwise be normal. (Jim) Right, right. Any other diseases, let’s say for grain sorghum? (Doug) Well, grain sorghum is again, similarly comes with a standard seed treatment. We have two soil born diseases that can affect grain sorghum, pythium, same one that affects soybeans. And then there’s a fusarium disease that affects it. In fact, we just had a case come into the K-State Diagnostic Clinic yesterday from north central Kansas, that had really a pretty nasty case of fusarium seedling blight. The good thing about fusarium seedling blight is it doesn’t necessarily kill the plant and it will recover. And you’ll end up with a reasonable crop. (Jim) Doug, we gotta take a break here, so don’t go away. And we want to cover more in detail the diseases of those crops again. So, don’t go away. Folks, you don’t go away either. And nows the time for you to get a cup of coffee and rush right back and we’ll see you in just a second.
(Jim) Welcome back to That’s My Farm. I’m Jim Shroyer, we’re here on the agronomy farm and we’re talking with Dr. Doug Jardine, our Extension Plant Pathologist about diseases this year. And we talked a little bit about diseases early on in the season and some problems. What about here and now diseases, what we’re seeing right now on say corn? (Doug) OK, well this was really a prime time for the foliar diseases on corn, because most of the corn in the state, with a few exceptions is just at tasseling or at silking. And when we have diseases that are gonna require a fungicide application this is the absolute best time to get them on. So, it’s important that people be out scouting right now to know what’s going on. And if you take a look historically in Kansas here in early July, Grey Leaf Spot is going to be our primary disease. And I’ve been doing some scouting over the last week or two and with all the spring rains and cloudy weather that we had, particularly through May and into early June, those are ideal conditions for Grey Leaf Spot. And in fact, we are seeing a probably higher than normal amount of that disease. I was talking to a consultant in south central Kansas just last week and he was estimating that of the fields he scouts and the irrigated acres about 70 percent of ’em were gonna need a fungicide, on the dryland acres about 50 percent. So, that’s quite a bit. People should be looking for that. It’s a pretty easy disease to identify, the kind of thin, rectangular lesions. They start on the bottom of the plant and work their way up. And we have guidelines available that people can check out, for what exactly those thresholds are. The other disease that they may be hearing a lot about, especially if they’re listening to the neighbors to the north in Nebraska and Iowa, is Northern Corn Leaf Blight. And Northern Corn Leaf Blight it’s these fairly large cigar shaped lesions, usually start in the lower to mid canopy. And in northern climates where they have a lot more cool weather through the summer, Northern Corn Leaf Blight is probably their primary foliar disease that they have to worry about. We’re fortunate here in Kansas, that with our normal summers, where we’ve already had some 100 degree days, that pretty much stops that disease in its tracks. But there is some Northern Corn Leaf Blight out in the canopy. We had several pictures and samples come into the clinic and people are wondering about it. Pretty easy to identify, but for our Kansas producers we just we’d really not like you to go out and spray specifically for Northern Corn Leaf Blight. Probably not gonna get your return on your investment. (Jim) North east, north central where is that gonna be? (Doug) You know you can probably find it just about any where. I mean they can even find Northern Corn Leaf Blight down in Mississippi and Louisiana. But typically in our normal summer, it’s not gonna develop to treatable levels. If there’s a little bit out there, and you’ve got Grey Leaf Spot, if you treat for one, you’re gonna get the other automatically. (Jim) Well what about Goss’s Blight? (Doug) Well Goss’s Blight is a bacterial disease. Over the last ten years, it’s really become important in Kansas. It overwinters on old crop debris. So where we have continuous no till corn is where it’s gonna be worse, especially if we get a little hail or blowing sand on it, that provides a wound for the bacteria to get in. And we have some resistance in our hybrids, but not really great. But the bad part about Goss’s Blight, is we don’t have any spray materials that we can put on once it’s there. You’re pretty much stuck. (Jim) With what you got. Doug don’t go away. Folks, now’s the time to take a break and we’re gonna be right back after these words from our sponsors.
(Jim) Welcome back to That’s My Farm. I’m Jim Shroyer, your host. And I see you’ve got a cup of coffee in your hand there. With us we have Dr. Doug Jardine, our Extension Plant Pathologist for Row Crops and we’ve been talking about corn, talking about corn disease like here and now. Let’s talk about down the road. (Doug) Well, as we get later into the season, there’s basically two groups of diseases that are of interest and they’re collectively called the stalk rots and the ear rots. And there are probably four different stalk rots that we can get in Kansas. And they each have their own specific environmental conditions that will bring them on. We also have three or four primary ear rots and again they have their own specific conditions that bring ’em on. If we want to go back to the earlier segment when we talked about all that water earlier in the spring, one of the problems it did is it took a lot of nitrogen out of the soil. (Jim) Right. (Doug) And depending on the producer’s ability to go in and side dress that we may have a lot of corn that is short of nitrogen for the rest of the season. And that is typically a prescription for disaster when it comes to stalk rots. Because what’s going to happen is the corn plant is trying to fill that grain and there’s not enough nitrogen in the leaves and maybe not photosynthesizing because they’ve lost some of those leaves due to nitrogen deficiency. The plant will start to cannibalize nutrients from the crown and the roots. (Jim) Remobilizing within the plant. (Doug) Remobilizing within the plant. And when it does that it allows a window of opportunity for those fungi that live in the soil to enter through the roots and then move up through the stalks. So, that you know, tells me right now that potentially it could be a big year for stalk rots, both in corn and grain sorghum. And so we need to watch that. If it’s wet later in the season it’s gonna be fusarium stalk rot. If it’s dry later in the season it could be charcoal rot. If you live in northeast Kansas, they get a lot of anthracnose stalk rot. So, it’s gonna have the same shredded symptoms when you split that lower stalk open, but there’s just minor details that would help you identify one from the other. And again, we have lots of picture bulletins that can help ’em. The bottom line is, it’s gonna cause yield loss and potentially lodging, so they have to be watching for it. (Jim) So, how does this play into next year, or that sort of thing, just the build up of the population of the disease? Anything like that? (Doug) You know, we don’t really see carry over from one year to the next when it comes to stalk rots. There’s plenty of inoculum in the soil naturally and it comes in through the roots, so that crop debris laying on the surface is not playing an important part, so that’s not important now. We mentioned ear rots earlier and that could be more important if we have…there’s two ear rots we might be looking for this year again depending on how the weather plays out the rest of the year. One is diplodia ear rot and diplodia is characterized by the slight white almost like shaving cream mold growth on the ear. And the primary conditions for that are when you get a lot of rain at tasseling time, silking time. And we’ve had that in some parts of the state. The other one we worry about is aspergillus rot, because that produces aspertox. And a lot of people are familiar with aspertox and that likes it kinda droughty and humid during the grain fill period. So you know that disease is down the line. We don’t know at this point whether that’s gonna be a problem or not. But those are things that they need to be watching for because both could result in significant dockage at the elevator. (Jim) Right, right. Doug, thank you for talking to us about the corn. We’re gonna take a break here and talk about soybeans here in a second so don’t go away. Folks, don’t go away either. Stay with us. We’ll be right back after these words from our sponsors.
(Jim) Welcome back to That’s My Farm and with us we have our Extension Plant Pathologist for Row Crops, Dr. Doug Jardine. And Dr. Doug, we’ve talked a little bit about corn and we’re standing in the soybean patch right now, so let’s talk a little bit about soybean disease. And so, tell me a little bit historically what’s been our major issues? (Doug) OK, well historically we do these annual disease loss estimates, at the end of each year. And if we look back over the last 20 years, clearly the number one disease in Kansas in soybeans is terminal rot. We mentioned it a little bit in an earlier segment. The one thing that people should know about terminal rot is it goes to corn, it goes to sorghum, it goes to soybeans. So, rotation… (Jim) You can’t rotate out of it. (Doug) Well to a point, because it turns out that there are some that like corn a little bit better, and some that like soybeans a little bit better… (Jim) Oh, you mean the strain of the charcoal. (Doug) Yea, the strain of the fungus. So if you go corn, corn, corn, you start to get to the one that really likes corn and the same with soybeans. So if you rotate, you’re still gonna get charcoal rot, but it won’t be too severe in any particular year. We mentioned it likes hot, droughty conditions. It’s a really tough disease because there are no chemical controls available for it. The companies continually look for seed treatments that will work. So far, we’ve struck out on that. There are no over-the-top foliar fungicides that work and quite frankly most of our varieties are pretty darn susceptible. Now there is a range of susceptibility from you now, bad to really bad. But they’re all still pretty bad. And so, the kind of things that you can do to deal with charcoal rot, typically are going to be reduced seeding populations. Because then if it gets dry later in the season there’s fewer plants competing for the available moisture. (Jim) Right. (Doug) And that actually seems to work pretty well and we’ve had research in the past in Kansas that demonstrates that. The seedling blight again, we mentioned a little bit earlier, the two primary ones that we get here in Kansas are pythium, which tends to be a little bit earlier in the year. And then our later planted double crop soybeans the disease du jour, if you will, is rhizoctonia. It likes a little bit warmer soils. They both like it wet. The good news is that we have plenty of seed treatments that really do a pretty darn good job if guys are willing to make the investment cause it’s gonna be several dollars an acre to treat that seed. But I think over the long run, they’ll be more than happy to do it. I kinda keep a seven year rolling average on yield increases from seed treatments. Right now it’s about two and a quarter bushel per acre. So that’s a pretty good return for a three to five dollar investment. (Jim) Right. (Doug) And then the last of these that we have is soybean systemetic that’s been in Kansas for 30 years. It goes mostly undetected because typically there are no above ground symptoms. And so guys need to soil test to make sure they have or that or they’re managing it if they have it. And it’s best treated by rotating appropriate resistant varieties. (Jim) Right. (Doug) Make sure you sample directly in the rows. Head lands are always a good place to look for it because it comes in with dirty equipment. And so that’s a good starting point to look in a field. (Jim) Doug don’t go away. I know we’ve got more to talk about on soybean diseases. Folks, stay with us, we’ll be right back after these words from our sponsors.
(Jim) Welcome back to That’s My Farm. I’m Jim Shroyer. And during the break Doug didn’t run off. And so Doug, I appreciate you staying here for this one last section here on soybeans. So, Doug talk to us a little bit about new and maybe emerging problems in soybeans. We talked about the good old standards, unfortunately, now let’s see what have we got coming. (Doug) Well right. That’s one thing about plant pathology we seem to have job security because just when we get one disease figured out, a new one comes along. Probably the most important disease that is actually…it’s been around 10 or 15 years now, but in the last few years it seems to have really blossomed, is sudden death syndrome. And sudden death syndrome is caused by a fungus that lives in the soil. We mentioned previously that it infects early and then kind of goes dormant and then if it gets wet during the reproductive phases, you’ll see it-the leaves will start to turn brown and they’ll drop off and you’ll have large areas of the field potentially foliated. (Jim) It’s a nasty looking disease. (Doug) It’s a nasty looking disease. The good thing is, is that there’s a new product out on the market called ILeVO, that works really, really well. I know all the university pathologists, we’ve had it in our testing programs. It doesn’t cure it, but it can increase yields, five or ten bushels an acre. It’s out this year on a limited basis. But that’s something that they might look for because that is probably the best thing that we currently have available. (Jim) It’s gonna be a game changer then I guess. (Doug) It is. It is. And there is some difference in varieties. But if conditions are bad enough, they all seem to kind of break down. (Jim) How is this related to soybean systemic? (Doug) Actually that’s a good question because since it enters through the roots if you get soybean systemic going in ahead of it, it kinda creates a little opening. (Jim) A pathway for it. (Doug) A little window of opportunity. It just follows that nematode right in the root. I would say at least 90 percent of the fields that we have sudden death in also have soybean system nematode. And the other 10 percent the nematode probably hasn’t built up to levels where we can detect it yet. (Jim) Right, right. So what’s the product again? (Doug) It’s called ILeVO. (Jim) ILeVO. (Doug) They’ll see it. And if they go out to company sponsored field days this year, they’ll see it in some of the trials and they’ll hear company personnel talking about it. But it is a really good product. (Jim) What else? What’s another disease? (Doug) OK. Well the one that I kind of worry about most is frogeye leaf spot. (Jim) That’s been a big one in the Mississippi River Valley, right? (Doug) Oh yea. From Mississippi River Valley up into Tennessee River Valley. Tennessee gets it terribly bad. Southern Illinois, southern Indiana, parts of Missouri. And in the last five or ten years we’ve seen it coming into Kansas, moving from the east gradually west. (Jim) What’s so bad about it? (Doug) Well it has the ability to explode really fast and suck nutrients away from the filling pods. It just gets a little nondescript brown spot with kind of a dark red ring around it. Some people think it looks like the eye of a frog and that’s where it gets its name from. We have good resistant varieties out there but unfortunately some of the most popular, high yielding varieties are susceptible. So, people need to be scouting for it, fungicides are available for use. But it’s just one… it’s not necessarily wide spread in Kansas, but with a rainy, wet spring like we’ve had, it’s one that could be there in the next month or so. (Jim) And so when…that’s what I was gonna ask, when do we see it and when do we treat it? (Doug) Alright so typically we’ll start to see it right around the flowering time of the soybean. Our window of opportunity for spraying is between the beginning of pod set and the beginning of pod fill. (Jim) So somewhere between R3 and then R5.5 and R6? Well R6 is probably getting a little late. (Jim) It’s too late. (Doug) Yea, you might get some benefit from it, but you’ve already let some of the horses out of the barn by that time. (Jim) Doug I really appreciate you taking time to talk to us about soybean and corn disease and problems we’re having across the state, or will have. And folks thank you for being with as well. And don’t forget we’ll be back next Friday with another show of That’s My Farm.
Closed Captioning Brought to you by the Kansas Soybean Commission. The Soybean Checkoff, Progress Powered by Kansas Farmers.