Entomology Update 8-4-23: Stink Bugs, Plant Bugs, and Bollworms

On this week's Entomolgoy Update, Extension Entomologists Ben Thrash and Nick Bateman discuss current rice stink bug levels and control, termination timing for plant bugs, bollworms in cotton, green stink bugs in soybean and more. 

Transcript

[00:01] Intro/Outro

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

[00:12] Ben Thrash

 Hey everybody, today is August 4th and we're going I guess give you a little update. Bugs are spotty this year, sounds like

[00:22] Nick Bateman

Have been all season.

[00:24] Ben Thrash

Yeah, that’s kind of the story. So, what’s happening in rice, Nick?

[00:30] Nick Bateman

You know. I mean, sure, there's still stink bugs around and we still got some rice not headed that we need to watch out for. But, but really I feel like ton of the calls I've got this week have been around getting to that third or fourth week of heading, running somewhere between 30 and 70% straw coloration, should I spray or should I not? And so, I think Aaron was here 2017, 2018 , former PhD student of Gus’ and he did a bunch of that work where we were looking at termination. I know we've talked about this before, but we were force feeding stink bugs on heads, and so they were caged on an individual head and so they were either forced to feed or die, right? Starve to death. So what we see is at 60% straw coloration, the chances of peck go way down. I mean, it it falls off tremendously. Would that being said, you know, getting up to that 60% mark, I would still like to be, you know, around half threshold going into that, not really that concerned about the numbers after that 60% mark. But going into 50-60%. I'd like to be about half threshold. And the reason that is, you know, if you look at the forecast next week, we allegedly got some chances of rain. We'll see what happens there, but it’s the same thing we see in soybeans, we see it in rice: We get some rainfall and you can soften them kernels up to where they can still injure it. So, you know, that that may be a bit related to some of the calls I've gotten this week have been running right at about 1 per 10 and maybe, maybe up to 12 on 10 or 10 on 10 to 12 on 10, those kind of numbers. You know, Lambda would, would get you 50-60% in that situation, maybe higher actually I’ve seen it do a little bit better this year than expected. But I don't think at this point, unless we're running you know, 2x threshold, there's really a need for Endigo, Tenchu at that point. Let’s try something cheap and get out of there. But you know getting a lot of calls on nymphs in these fields that we're not treating right now with low numbers of nymphs – Same way we talked about barnyard – they're going to be adults by this time next week and they're going to be looking for green rice to go to. So if you got rice that just now starting to head, really need to be checking it next week because these stink bugs are going to start condensing down to whatever’s left that’s green. That’s pretty much it there. 

[03:03] Ben Thrash

Well, in cotton, you know we're winding this crop down pretty quick as far as plant bugs go and soon to be worms. It looks like most of my cotton is I think about all my cotton's past cut out and really next week will be about termination timing for plant bugs on most of my stuff. And that's kind of what I'm hearing from everybody. And I've heard some issues with control of plant bugs over this past week for sure, but anthing guys went with and I really think a lot of it is just getting good coverage. A lot of  this cotton that’s lapped up, it's big plants, plant bugs get down low in the canopy especially in all this heat. I think coverage is why we're not getting really good control of these plant bugs and why nothing is seemingly not working. So, if you got to go out for plant bugs, just try to get as good a coverage as you can whichever way you're going out. With that being said, the last effective bloom date up in North Arkansas, like I said last week, is coming up. It's like August eighth. So that's only in four days. So, you know, there's not much to protect after that. As far as blooms and squares type deal goes. The plant bugs are spotty. Some people say they got a really heavy pressure in some areas and then some guys are like, man they disappeared on me. So it's spotty kind of like everything else, like the worms are as well. We, me and Nick have been scouting a lot of worm trials this past week too. Down at Tiller we got, I've got everything under the sun out there. I’ve got Bt, non-Bt, three-gene, two-gene stuff. The worms are really really thick in our non-Bt stuff, we're pretty much at 100% damage on all our fruit and structures out there in that cotton and the Bollgard 3 has a bunch of eggs in it, but we're really not seeing anything getting through it. I’ll find, you know a damaged square or two, kind of up at the top in some of the three gene stuff, but you really can't find any worms that are bigger than a, than a neonate. You know, so it  seems to still be working good, so, I mean, I'm not recommending anybody treat any Bollgard 3 cotton for worms. But like I said, talking about worms, they’re spotty this year. Guys are telling me they have a 400 acre block and they'll go out there and they'll sweep all these fields out there and they'll be one 40- acre block. Everything's the same growth stage and soybeans and, you know, there's worms in that one block and everything else around it there’s nothing in it. And that's kind of what I'm seeing when I'm going to fields and looking at them is there's fields that look ripe for bollworms. I mean, they look like I’d bet money that there’s boll worms in those fields and you go out there in them and they're not there. So I’d just be out there scouting really hard, be out there looking for these really small worms when they when that first hatch. Nick, before we got on here, you were you were talking about stink bugs a little bit in soybeans. And you know, what you been hearing?

[06:50] Nick Bateman

Yeah. I mean, it's the same thing you’ve been saying about spotty. You know, we were getting quite a few calls on two or three weeks ago and it now it sounds like they're just kind of sporadic here and there. Could be because we had maybe similar to rice and having a bunch of rice headed out, it maybe because we have so many beans in that R5.5 to R6 window, but you know, we've been saying with greens you can get away with something like Lambda. Ben made a good point for we started recording, you know you start getting up to close to one per sweep, you know, 20 to 25 on 25 sweeps. You might consider going with a little bit higher rate of bifenthrin or maybe like a half pound of acephate. I mean Lambda’s good on them, but at the same time higher numbers you'd probably want to use something a little bit stouter on them than just Lambda by itself. Yeah but keep in mind there that in in R6 we're going to double, for greens and browns we're going to double that threshold up to 18 and at R6.5 we can walk away. With red bands and honestly I haven’t got any calls on red bands I think I had one this week and the guy had been watching the field for I think the two or three weeks now running about half threshold and this week he was, he was up around six or seven so they went ahead and sprayed. But it doesn't sound like they're really building on us too bad right now. So hopefully we'll out run a lot of that. But keep in mind the threshold, there is 4 on 25 and we're going to double it, or well not double but we’re going to go up to 10 at R6.5 and terminate at R7. So there's a little bit of a difference there between those.

[08:33] Ben Thrash

Yeah. And then I mean we had, it seemed like last week I was getting more looper calls than, than this week as well. And you know, I was talking about insecticide choices and, you know, I might be a little careful. You know, last year some guys went out with Intrepid and they had some issues with it with regular old Intrepid, just the Methoxy, and they had some issues with it. And then I heard people, you know, they'd have stink bugs and loopers and so they'd run Intrepid plus acetate. And a lot of those guys had really good control with that mixture out there. But Intrepid Edge and Denim are two of our star, you know, Looper products out there. So I'd recommend going with that Denim or Intrepid Edge if I was going after loopers. But if you're still going after corn earworms with good population, I'd definitely run a diamide like Besiege, Vantacor, Elevest or something like that out there after them. But, you know, Nick, you mentioned getting some calls on green clover worms as well. And, you know, I had some of them last week, too.

[09:47] Nick Bateman

Yeah. And not trying to make green clover worm some big major pest at all.  Look, some of the calls were getting is running up close to one per sweep and around that 10%, probably defoliation deal. And keep in mind in reproductive beans that thresholds 25% defoliation and it takes a ton of green clover worms to get up to that point. You know 10% defoliation there's no yield loss associated with that. With green clover worms I'm going to try to wait another week to see if that defoliation’s building because you throw a pyrethroid out there especially at this time of year and clean up green clover worm, you're liable to be right back in behind it a week, ten days later, killing loopers or bollworm depending on if you already bloomed or not, that pyrethroid just to take out something that you know me and Ben joke about it being beneficial because it brings a bunch of parasitoids and whatnot to the field, brings in a bunch of beneficial insects, there. You know, I just hate running a pyrethroid there and opening up the window for more issues.

[10:52] Ben Thrash

Yeah, for sure. And I've heard very little on army worms. I mean, up in the River Valley, one of my brother's buddies, he was, he had some hay. I went out there and I was doing sweeps and he's I like have about ten of them. And usually we're kind of a hotbed for loopers up in the river valley. I mean, for fall army worms up in the River Valley. But I didn't really hadn't heard much or seen much on, on the army worm front thus far. Have you heard anything different, Nate?

[11:29] Nick Bateman

No. We had some calls last week about folks spotting some in headed rice but it seems like it's petered out pretty good, or at least I'm not hearing from folks about it anymore. And I looked in a lot of their signalgrass and whatnot around the station here and other day down there with you in Tiller and just really not seeing any again. Not saying they're not going to build on us toward Setember and we might have to treat a little bit of pasture ground or maybe a little bit more rice, that kind of stuff. But right now it just doesn't seem like it's going to be a major deal. 

[12:03] Ben Thrash

Yeah, yeah. Well, that’s about everything I got Nick, I reckon.

[12:07] Nick Bateman

Yeah, and I think so. I mean it really. I think we might deal with a little bit more insect pests. There's a, there's a few beans not blooming and what not right now that might catch a pretty good flight of bollworms or some of this late rice. But it's been a pretty cheap year overall. It's, it's been good.

[12:27] Ben Thrash

Yeah. And I think, I mean, there's still plenty of time for loopers. So keep your eye out for them. But, yeah, some of the stuff's wrapping up pretty quick with all the heat that we got right now. 

[12:40] Nick Bateman

Yeah, very much so. 

[12:42] Ben Thrash

Well, if you need us, call us, my numbers. 501-517-3853.

[12:47] Nick Bateman

Mine’s 870-456-8486.

[12:53] Ben Thrash

Alright, thank you.

[12:53] Intro/Outro

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