Entomology Update 8-11-23: Stink Bugs, Insecticide Termination Timings and Salt Marsh Caterpillars

On this week's Entomology Update, Extension Entomologists Ben Thrash and Nick Bateman discuss termination timing for insecticides in cotton, stink bugs, salt marsh caterpillars, loopers 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 11th and really it's kind of slow out there. Which kind of seems to be a recurring theme throughout most of the year, I guess. Anyways, Nick, you want to go ahead and talk about what's going on in rice?

[00:32] Nick Bateman

Yeah. And it's kind of the same story from the past week, two weeks. A lot of this rice getting up there that 50-ish percent straw coloration, maybe a little less, a little more. But either way, getting close to pulling the boards on a lot of it and starting to see several stink bugs show up in that, you know, the little low levels of adults we had for several weeks out there, they finally laid eggs we're seeing nymphs. Look where I'm at on that, you know, 60% hard dough is where we can terminate. If I'm running I’m gonna say 15, 10 to 15, because at that 60%, I still would like to be around half the threshold. You know that that's a window for lambda that 10 to 15 if it's over 15. You know, I don't think you can trust Lambda because if you don't get, you know, you're 50 or 60% there, if you only get 40, you’re still leaving too many stink bugs. So I feel like that's kind of a fit for it. And I'm hearing numbers anywhere between right 10 on 10 sweep upwards of 25, 30 where we've had big nymph hatchs out. We're actually, if it don’t rain us out here in a few minutes, spraying some stink bug trials this morning and we're seeing quite a few of them in some green rice, some of these pockets around a bunch of it that’s been drained and that kind of stuff. That's not out of the ordinary, but really be looking after a bunch of that green rice right now. But that's, that's pretty much it there.

[02:02] Ben Thrash

Yeah. In cotton you know we're talking about terminating a bunch of stuff. I terminated a bunch of my plant bug trials I had this past week because I mean, we're past the point. It's node above white flower 5 plus 250 heat units, which is cut out for plant bugs, boll worms is cut out, plus 350 heat units. Just keep that in mind. And, you know, we're at the last effective bloom date for a lot of the state. In South Arkansas I think you still go to about the 21st for your last effective bloom date. But, you know, as you go farther, farther north, it's really kind of past point no blooms that that you have on the plant are gonna are going to end up making a boll or there's a low likelihood of them making a making a boll. So you know, kind of the end of the tunnel, I guess you said that a light at the end of tunnel for a lot of this cotton crop. And soybeans, you know, we're still hearing some stink bugs here and there. I mean, Nick, most of what I've been hearing has been greens. I mean, I've heard a little bit of browns.

[03:24] Nick Bateman

Yeah, I’m gonna say like 90% of it being greens and then you got them oddball fields that are dominated by browns.

[03:29] Ben Thrash

Yeah. Yeah. And look, if if I've got greens out there in the field and I'm like, what? I don't know if I'm probably running up to 18 or something. 15, I'm probably just going to run Lambda. But if I, if I start getting more than that on greens, I'm on a swap to a bifenthrin and or an acephate, not together. That's overkill mixing them together for just green stink bugs. I'd stick to lambda unless I had a really, really high number and needed to get them under control. If you got browns, I'd probably I'd rather run some acephate. Um, let's see. I know I've also been hearing calls on. On salt marshes and Nick, you had too, hadn’t you?

[04:21] Nick Bateman

Yeah, it's like everything else just kind of scattered, but where they are it’s pretty good numbers.

[04:29] Ben Thrash

Yeah. Yeah, it's just kind of spotty. I've got just a call or two on salt marshes and a matter of fact, we got some on the station over there at Marianna. And if it doesn't get rained on, I'm gonna try to put a salt marsh caterpillar test out today, but if you got them, remember, they're just defoliators, and you don't need to, you know, treat them like they're corn ear worms. I mean, you got to wait for defoliation, too, to treat them things and a pyrethroid doesn't do real good on them. Gus said in the past, you know, I talked to him because this don't happen all the time. But salt marsh can be hit or miss with a pyrethroid. So if you got to go after some, I'd recommend doing like four ounces of Intrepid or one of the knock offs I think Troubadour, TurnStyle, one of those I'll tell you it's TurnStyle. But one of the methoxy products, run that at four ounces to take care of salt marsh that's probably gonna be your cheapest option. Um, and then loopers, Nick you heard some stuff about loopers.

[05:44] Nick Bateman

Yeah. And I mean, you know, you sprayed them tests earlier this week down at Tiller and that's some of the highest numbers we've seen. But, you know, a bunch of these folks I was talking to two or three weeks ago that they were starting to catch, you know, 2 to 3 on 25 sweeps. It sounds like they're still hanging out at 2 to 3 on 25. And me and Ben, we've been talking all week about, you know, this is kind of whether to make loopers crash. But we're also in the first ten days of August or so. And, you know, we still got a lot of season left. It's hard to say if it wipes out this generation with this weather, if we're not going to have another one or what's going to happen here. But it sounds like right now they're just kind of lingering. They're not really building, but they're not really going away.

[06:28] Ben Thrash

Yeah, that's the same thing I've heard is that there's some out there, but there isn't any more than I had last week, you know, so.

[06:37] Nick Bateman

Yeah. And I think on the soybean front, tell you one thing we need to reiterate on is termination. Look at R6.5 we're done outside of red banded stink bugs. We're done from an insect standpoint. And a lot of these our early beans are at that point or passed and it seems like at this point so.

[06:59] Ben Thrash

Yeah and remember on stink bugs once you hit R6 you double your threshold at termite at 6.5. Yeah. But if you got loopers I'd recommend Denim or Intrepid Edge. Um, you know, don't run. I wouldn't recommend running the diamide. We've been missing quite a few this past year and people have been asking me about running a regular old Intrepid or one of the generic Intrepid's. Now, like I said, some people had some issues with it last year, but I put tests out two days ago and I'll be back in there to check them on Monday and we'll let everybody know how those how those tests turned out. But, you know, I really don't know what it's going to do this year. It may wipe them out, it may might leave them, so.

[07:56] Nick Bateman

That’s where loopers get finicky, You know, we inherit all them problem from South America, so we don't really know year to year what those problems are going to be.

[08:04] Ben Thrash

Yeah, that’s right. Nick, you got a couple of calls on grain sorghum hadn’t you?

[08:14] Nick Bateman

Yeah. And it's you know, there aren't a lot of sorghum acres out there, but it sounds like sugarcane aphid’s starting to build some, particularly on the edges of the field and seeing a lot of head worms in it. Some of these areas are notorious for getting web worms in there as well. And I heard questions, you know, running Heligen versus Vantacor you know, something like that. And, you know, just keep in mind, if you run Heligen it’s probably going to work pretty well in sorghum because them heads are exposed and coverage is going to be good. But that's all you're going to control is that that boll worm, that head worm up there. And you're, if you got a history of having a lot of web worms in there, I would lean towards something more like Vantacor. And the reason I would over Besiege in that situation is because you're removing that pyrethroid, less chance of blowing those aphids up. Now if you're doubling up, spraying aphids and head worms or whatever caterpillars you got out there and you want to run a diamide, get whichever ones cheapest. Besiege is gonna do fine, Vantacor is gonna do fine. That pyrethroid portion, if I’m not spraying sugarcane aphids is what's going to end up making them blow up.

[09:29] Ben Thrash

Yeah, yeah, that's right. And then we were also talking. I mean, I hadn't heard anything more on fall army worms and I really hadn't been seeing any out there in in any bremuda or anything like that. I mean, I picked up like a couple the other day in some weeds, but really, I don't know. The population just doesn't seem to be there this year. Not at all. Yeah. So, I don't know. That's all I got, Nick.

[09:58] Nick Bateman

Yeah, I think so. You know, it's been kind of same story all year, slow.

[10:04] Ben Thrash

Yeah, yeah. Little, little weeks here and there. Little excitement, I guess, but if you need us, call us my number is 501-517-3853.

[10:17] Nick Bateman

Mine’s 870-456-8486.

[10:21] Ben Thrash

Alright. Thank you.

[10:24] Intro/Outro

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