Lorenz, Bateman, Thrash sound the alert on stinkbugs, fall armyworms and plant bugs. (7/1/2021)

URGENT message from Division of Agriculture entomologists who are seeing significant numbers of stinkbugs poised to raid early rice when heading begins; urge growers to avoid making applications too early.  Be on the lookout for corn borers, fall armyworm in beans, plant bugs in cotton and midge in sorghum. 

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Title: Sound the alert on stinkbugs, fall armyworms and plant bugs (7-1-21) 

Arkansas Row Crops Radio providing up to date information and timely recommendations on row crop production in Arkansas.

Ben Thrash: Welcome to Arkansas Row Crops Radio, my name is Ben Thrash, extension entomologist for the University of Arkansas System Division of Agriculture. And today we’ve got Nick Bateman & Gus Lorenz with us today. So we’re going to talk a little bit about what’s going on with insects out in our row crops. Nick, you want to kick it off with rice?

Nick Bateman: Yeah, we can, so you know we’ve talked about rice water weevils a lot over the past month. I haven’t seen many of adults around here lately. It looks like we’re starting to cycle through. So they’re probably, but be aware if you’re still going to flood, it’s going to be attractive, especially that small rice, so if there are still some around you need to get out there and be vigilant. As far as rice stink bugs go, you know we’re getting into boot split, getting into late boot and some of this early rice and you know that lines up about that time about fungicide timing, right and we put that dollup of Lambda in there. You know we don’t agree with that, we don’t see the benefit of it. We know there’s a lot of that going on. We also think it could be part of the issue we’re having with some of the misses late in the season with rice stink bugs with Lambda. The threshold for that for rice stink bugs is going to be five to ten sweeps during that first two weeks of heading and ten for ten sweeps the second two weeks. We’re going to wait until we’re 75% headed before we start sampling it. We need a majority of that field headed out before we start sampling. But based on all the assay work we’re doing currently over the past month and a half it looks like Lambda’s working fine now, but you know we need to be checking behind those applications a little quicker than we usually do. Three to four days afterwards and if we’re seeing any nymphs behind those applications that could be a sign, that is a sign that we need to swap to another chemistry and your only other option there is Tenchu. That’s about all that’s going on right now in the rice world from the insect standpoint. 

s From what I can see, you know, and you know we don’t like to make predictions or anything, but because you know I’m always wrong on that stuff, but based on what we’re seeing on wild hosts and in corn and stuff like that, there’s a lot of rice stink bugs out there, and I think when this earliest rice comes out there’s going to be a lot of stink bugs coming into the rice fields when that head starts coming out. That’s what attracts those rice stink bugs to the field is when that head starts coming out. That’s when they really start falling in the field in big numbers and I expect to see a lot of fields early, particularly these early fields that are the only rice fields in town for the stink bugs and that’s what we normally see is when they, when the first fields start heading is when they get covered up and then as more and more rice gets to head they start dispersing over the landscape. But I think these earliest field are liable to take a pretty big hit, don’t you Nick?

Nick: Yeah, and you know Gus has mentioned those wild hosts. Talking about the asci’s we’re running, so we were up around Tuckerman a few days ago and there’s some johnsongrass up there and we collected about 800 stinkbugs in about ten minutes. We were running about 5 to 6 per sweep. So there’s a lot out there native vegetation right now. We made another collection out of some barnyard of course and dallasgrass. They’re on all these grasses that are up and down the turnrows and ditches right now.

Gus: Yeah we seen that in the past and sometimes it doesn’t mean that when the rice starts heading that they fall into the rice like that but in some years they really can cover it up and we’ve seen numbers as high in rice fields that were early heading over a hundred per ten sweeps and that kind of thing. So the potential’s out there, but I think we need to be watching for it, but like you were saying that spraying before the head emerges and expecting that to give you some level of control, and what we’ve seen in the past is people make an early application and then about a week later the head starts coming out and you get this big influx into the field and you have to treat again, and sometimes twice because the numbers are so big and the potential there is it may take two applications this year and if you make a too early application you may be making three applications. And that’s kind of what we want to avoid. Anyway.

Nick, Ben?: We want to move over into soybeans. You know there’s still a lot of army worms out there and they’re probably going to keep on keeping on for a while. And so if you’ve got, particularly if you’ve got grassy fields that you’re treating with Roundup, you’re going through there making your herbicide application, check that grass out there in the field for armyworms before you go across the field. If it’s loaded with armyworms, you can go ahead and throw a pyrethoid in the tank and knock those out because when those armyworms are big, they can move over on some beans and really cause some really, really quick defoliation. There’s still stinkbugs out there, so just keep an eye out for stinkbugs. Our moth traps, they’re still being a little weird for bollworms. We had a trap down south that caught a thousand bollworms moths in four days. But then the rest of our traps, there weren’t just a whole lot in them. 

Gus: There was one that had three or four hundred in it and one that had eleven hundred in it and the rest of them, nothing. So it’s really weird.

Nick, Ben?: It’s real spotty. They’re out there. Most of them are probably going to corn, but you need to out looking in your beans because they can still get in those beans. So keep an eye out there.

Gus: Yeah, we were walking some fields the other day and there was a lot of broadleaf signal(?) grass around and the fall armyworms were thick in that broadleaf signal(?) grass. It was unbelievable how many fall armyworms there were. And I’m sure you’ve been hearing about Louisiana and Mississippi both having problems controlling falls with pyrethoid applications and that’s why we’re encouraging, if you use a pyrethoid, get behind that application in about 3 or 4 days and make sure that you got control of the fall armyworms because it appears that there may be an issue coming up with a little bit of pyrethoid resistance with this grass strain of fall armyworms. So something to keep in mind.

Moving in to cotton, right now we’re in that plant bug situation and a lot of people would tell you that the plant bugs are as bad as they’ve ever seen them for this time of year. You know we’re transitioning into getting close to bloom on a lot of cotton right now. And you know, you talk to one guy and his cotton is about half knee high, about 9 or 10 nodes, not much going on, not many plant bugs. You talk to the guy that has some early planted cotton, got cotton up about knee high and the plant bugs are just unbearable and a lot of cases the adults coming in the field right now are upwards of 14, 15 per 25 sweeps and our threshold is 8 per hundred. So when you get 10, 12, 14 per 25, that’s a lot of plant bugs moving in the field and they are impacting some square retention in a lot of cases and it’s usually next to corn or where there’s a lot of plains coryopsis (?), the yellow flower that you see out there, black-eyed susan or whatever you want to call it. But there is a lot of plant bugs moving into these fields it seems like right about the time they’re getting ready to bloom or starting to bloom and the numbers are extremely high right now, particularly next to those wild hosts in corn, so we encourage you to scout those fields next to that corn and then get out some and see what’s going on in the middle of the field and look at the difference to see if you can make some boarder treatments or whatever. But in those cases where those plant bug numbers are high and we’re in that third week to fourth week of squaring and getting close to bloom, and you got those kind of numbers, I think a knockdown material plus some Diamond and we go with 6 oz. I know some people got different rates that they like, but based on our work that 6 oz rate works plenty good and put some kind of knockdown, you know if you’re not blooming you’re limited on what you can go with and it’s like, if I got those kind of numbers, I’m not going with less than two and a half ounces of Centric or maybe Transform. A lot of people don’t like to shoot that bullet on Transform until they get right into bloom, but with the numbers that we’re experiencing, our stopper to stop these plant bug populations for the last several years has been Transform and that’s what a lot of people are resorting to at this point to get control of this situation because we’ve talked about this several times, getting control of these plant bugs before we get into canopy closure is extremely important. So all that stuff, take it under consideration. If you got any questions or problems, don’t hesitate to give us a call. But the cotton, the plant bugs are really bad this year. We also got some mites popping in, and aphids and that kind of stuff. A lot of the secondary stuff is probably associated with a lot of foliar applications of Acephate and other products early in the season for control of thrips and now as a result of that we’re seeing that kind of situation pop up where we’re getting aphids and mites and that kind of thing. So just remember after the first shot of Abamectin you need to change chemistry and try something different like Portal or Zeal or something like that. You need to make a change.

Last thing is the milo. And we’ve had a lot of calls on midge this year. More so than normal. It’s just another one of those insects that looks like it wintered well or whatever, but there is a lot of midge out there. And definitely the sugarcane aphid is here. And it’s all over the state I think by now. We were seeing it Phillips County and now it’s in Lee County and it’s moving around and it’s showing up. If you get out there and scout for it, sugarcane aphid’s out there and if you treat a pyrethoid for midge control, you know what happens with sugarcane aphid. They blow up so keep that in mind. The bollworms now that we got hidden, we got sorghum everywhere, I think the bollworms and fall armyworms are going to move in and there’s just a lot of stuff going on right now with the grain sorghum crop that we got. And there’s a lot of falls out there in it too. I’m getting a lot of calls on even milo that hadn’t started heading yet. There’s a lot of worms that are already in it and we don’t worry about that too much about the worms in the vegetative stage of milo production. We’re more concerned about that getting them in the head and taking care of them when, about one per head is our threshold on that. So considerations for midge, you know if there’s any Blackhawk out there, you might consider that. If not, you’re going to have to treat with something like Dimethoate or a pyrethoid last choice you know in that situation. But those are kind of your options. Just give us a call if you get in a situation where you need some help and you think we might be able to help you. On those sugarcane aphids, we’ve been looking at sievanto and Transform for several years. They both do a good job. I think if you have to fire that first shot, you might look at making some boarder applications. If it appears like sugarcane aphid is doing the same thing it’s done the last several years where it starts on the boarder of the field and hangs there for a while before it moves in, so you might be able to make some boarder applications to catch these sugarcane aphids and buy you some time. 

Nick: Now corn, the southwestern corn borers, they’re here. Over around Cotton Plant they’re catching around 200 per trap. So if you’ve got any non BT corn you really, you need to be out there looking and seeing if you’ve got any corn borers. Checking your traps and stuff like that. What else?

Ben: Anything else Nick? Ok. That’s it. 

Thanks for joining us on the Arkansas Row Crops Radio.

End notes: Arkansas Row Crops Radio is a production of the University of Arkansas System Division of Agriculture. For more information, please contact your local county extension agent or visit uaex.uada.edu.