Entomology Update 8-22-24: Termination Timings in Cotton, Stink Bugs and Salt Marsh Caterpillars in Soybeans

Extension entomologists Nick Bateman and Ben Thrash discuss treatment decisions for rice stink bug in late planted rice, termination timings for plant bugs and stink bugs in cotton, stink bugs in soybeans and more.

Transcript

[00:00] Intro/Outro

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

[00:11] Ben Thrash

Hi everybody. Today is August 22nd and you know it's getting near the end. Things are kind of slowing down, but there's still a few bugs out there you gotta, gotta worry about. Nick, what's happening in rice?

[00:27] Nick Bateman

Same story as the last couple weeks. A bunch of this rice that’s just starting to head, and I know there's not a lot of it out there, seeing some pretty dadgum high stink bug numbers in it. You know, in the plots we sprayed a couple weeks ago, our untreated is into the running up in the 50s now. We actually went and collected some stink bugs up around Lonoke earlier this week for some various stuff we're doing. And that rice was about 75% headed and we were catching anywhere between 30 up to 60 and 70 on ten sweeps. So if you got any that is starting to head, better be looking at it and looking at it pretty hard. The other thing we’ve gotten a few phone calls on this week, some of these fields that are 30, 40% headed and running some of those 20s and 30s and whether or not we should treat and those are some pretty high numbers. The, the to me, especially if you're going to use a product like Tenchu, I'd prefer to get as many heads out as possible before I spray. Because that's where you're going to maximize your residual. There's there's a little translocation and stuff there, but it's not a lot. so I think if you're in that situation where you're 30, 40% headed, but you're running some 30s and 40s, that kind of thing. I would probably get ready to treat it, but I might would try to wait another 3 or 4 days. It’s supposed to warm back up. So hopefully it'll it'll catch on up and get 75, 80% headed by the time it gets treated, but that's, that's pretty much it right now. Stinkbug numbers are picking up, but it's on a pretty small amount of acreage. I, I mean, you got rice that’s not headingor just starting to head, I’d be looking at it.

[02:13] Ben Thrash

Yeah. I mean, in cotton. We're getting near the end. You know, if you're, you know, just looking at our termination timings for, for insects. So plant bugs, you know, just a reminder it's 250 heat units past cut out for stink bugs it's 450 heat units past cut out. And, for spider mites, you know, if if I'm at 600 and I've got, like, a low population, I might let them, ride. But if I got a heavy population and I'm out there about 600 heat units, I'm probably going to go ahead and I'm going to spray them, on out. You know, just remember, you don't want premature defoliation, out there in that cotton. And it can really end up partners yield wise there in the end. If if you do end up letting that cotton get prematurely defoliated. The last effective bloom date has kind of came and went for the whole state now. So remember, with each day passing this point, your chances of a bloom actually making a boll are getting less and less. So just kind of keep that in mind. It just, you know, are you really going to make your money back on trying to make an insecticide application, trying to save some blooms or anything like that there at the end? Nick, how about there's there's a few bugs out there in some beans. What what are you hearing?

[03:43] Nick Bateman

Yeah, there's the stink bug. I mean, I feel like we've been dealing with stink bugs all year. It's been one, you know, one constant. It feels like in soybeans has been stink bugs. And a few of the phone calls feels like there's a few more browns out there than than earlier in the year where you'd be looking at running, you know, more of a acephate or really high rate of bifenthrin compared to, you know, like a lambda. but, you know, it seems like a lot of them numbers are building, right there at R6, eggs hatching out and a bunch of nymphs. And just keep in mind that threshold doubles R6 from 9 to 18. And then you can terminate at R6.5. And then it sounds like a lot of the loopers the y'all we're seeing down south over the past couple weeks have started crashing, at least in some areas.

[04:35] Ben Thrash

Yeah, it it seems like areas that got rain, people are having some loopers crash on them, which is good for the farmers. But then it sounds like the areas where they didn't really get any rain, the loopers are kind of holding strong. I mean, I talked to some somebody up around Marianna this morning that sprayed some loopers. I think yesterday morning. And, you know, we checked our our Looper trial yesterday and there was there were still plenty of loopers over there on the station at Marianna, whereas my loopers down south, where we actually did get some rain the other day. they completely crashed. I talked to a couple other people down south Arkansas that had some loopers crash, so, it's kind of just seems like where there was some rain, there was some moisture, and that just really allowed some disease to develop and crash those looper populations in those areas. So, you know, just kind of keep that in mind. before you treat, before you treat any loopers just kind of depends on where you're at. It sounds like.

[05:42] Nick Bateman

Then it sounds like then phone calls kind of transition in a lot of areas from loopers to Salt Marsh this week, seeing a lot of big hairy caterpillars in beans at varying levels. and those things can cause quite a bit of defoliation. Especially when they get big.

[06:01] Ben Thrash

We had a test out last year, and, you know, most products look pretty decent on the salt marsh, even like Lambda plus acephate. But, you know, what didn't look good was pyrethroid alone. So stay away from that. intrepid. Looked good. Intrepid Edge looked good. Besiege. all those products all look pretty good on it last year. But, you know another thing, we got some, a few, bean leaf beetles out there that I'm hearing about. And now we kind of talked about that last week that they're really actually kind of hard to control. And you got to do a tank mix on them or use a premix product if you're going to get good control of them. I'd run something like Indigo or Acetate bifenthrin, or you might even be able to, you know, do like a imidacloprid type mix or something and do do all right with them too but just kind of keep that in mind. They aren't the easiest thing to kill. I probably wouldn't go out with just acephate or just a pyrethroid. I definitely wouldn't go out with a pyrethroid alone. But, anyways, they're a little tough. but then another thing I guess I heard was, there's a few velvet bean caterpillars around. And remember those velvet beans they're easy to kill, but they eat a whole heck of a – they eat more like a looper. They eat a lot of, a lot of leaf area. not like a green clover. you know, green clover worm. They can be, you know, 40 or 50 of them out there, and they just kind of rag the tops up. Where do you get that many velvet bean caterpillars out there they can defoliate your bean really, really good. So, but, you know, a pyrethroid will kill them too. So they're not they're not all that tough to kill. Anything else? Nick?

[08:05] Nick Bateman

No. Not really. I had a call on some armyworms in millet. I mean, they're they're still right on. And they're still doing pretty high numbers on turn rows and stuff. So if you got some millet or planted some early wheat for food plots that sort of thing, just keep an eye out.

[08:23] Ben Thrash

Well, if you need us, cause my number is (501) 517-3853.

[08:28] Nick Bateman

Mine’s (870)456-8486

[08:33] Ben Thrash

Thank you.

[08:35] Intro/Outro

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