Entomology Update 8-1-24: Fall Armyworm in Late Rice, Stink Bugs in Cotton, Soybean Loopers

Extension entomologists Nick Bateman and Ben Thrash discuss fall armyworms in late rice, stink bugs and plant bugs in cotton, soybean looper, redbanded stink bug 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 1st and there's a little bit of stuff going on out there. But what’s happening in rice, Nick?

[00:23] Nick Bateman

I’m still getting a few calls on armyworms, especially some of this super late rice. I mean, we sprayed some tests, I don't know, seven, ten days ago now, and the rice is just now getting to like, half-inch, so it’s super late. And it seems like some of that really late stuff out there right now is really kind of a hot spot for them. But I have had some questions around the Intrepid 18. I should have updated you already. I didn't think about it. So we're still legal under that crises. If you go to the bottom of that label, when you look at it, it has a statement in there that says, as long as EPA's reviewing the full Section 18, the specific exemption then the crises stays in effect. So we're still legal to use Intrepid in rice. You know it seems like the fall thing has died down for a majority of those acres. It seems like it's probably a bigger issue on pasture right now. And then on a stink bug front, you know, majority of the calls I've had in the past like seven, ten days, it's been folks that have been running really low numbers for, you know, a couple of weeks out there and now the egg are starting to hatch and we have nymphs. And, you know, in some cases this is occurring right around the termination timing, that 50 to 60% straw-colored kernels. You know, for me, that's a spot where I think lambda is still a fit especially if I'm running, say like 15 or less, you know, and if they’re small nymphs maybe you can push it a little bit farther with a little bit higher rate. But generally at that point if I’m anywhere close to that 50 to 60% of strong colored kernels, if I can keep them below the threshold I’m fine to walk away from them. So that's a good cheap option to cut them in half if that’ll get you down below threshold. If it won’t, you're probably looking at Tenchu but you don't really need a residual at that point, you’re really just looking to cut them in half going into that. One thing about it we do have growing conditions on our side for the next 7 to 10 days. So the quicker that rice can get past that 50 to 60% straw-colored kernel mark, the less chance there is that stink bugs can injure it. But really, that's that's about it. I mean, I think this last a little bit of rice to head is probably going to be be pretty thick with stink bugs. They’re going to be looking for a place to go especially now that we've got a few combines running around the state with a lot more that'll be running over the next seven days or so, they're gonna start congregating down. But but right now, stink bugs been light and army worms are still really sporadic and spotty.

[03:08] Ben Thrash

All right. And in cotton, you know, we're kind of getting getting towards the end for for bugs, at least plant bugs. You know a lot of this cotton's node above white flower five so at cut out you know we terminate spraying for tarnished plant bug 250 heat units passed cut out something though that I'm actually seeing quite a bit of in in some of my plot is I'm picking up a pretty decent number of a stink bugs out there and so you can't terminate spraying for stink bugs until 450 heat units out past that. And just remember Transform if you're if you're running Transform for plant bugs and you got some stink bugs out there, Transform and do anything for those stink bugs. You're going to have that run either bifenthrin, acephate, Bidrin. That’s your three options for for getting good control of of stink bugs out there. You know we're also getting close to our last effective bloom date. Down in south Arkansas. It's around August 21st. I ever up in north Arkansas around August eight. So just keep that in mind when you know, you're deciding whether to make applications and what what bolls you know, or what squares you actually think are going to end up making making a boll. I'd say just remember also though on plant bugs that once you do get past, once you do get to cut out your threshold doubles for plant bugs and so you might be able to save a few applications there. I guess that's all really going on in in cotton right now. It sounds like our spider mites have kind of died down a little bit after all that rain we had over the past, you know, last week and stuff. It was a rainy, boy, we scouted all day, every day. It seemed like in the in the rain, all of our plants last week. Didn't have a dry day. But anyways I guess what's happened beans, Nick?

[05:33] Nick Bateman

Nick Bateman

Yeah there's still some scattered stink bugs around. It still seems like, I mean it's not unexpected. They're seed feeders, but it seems like a lot of these beans I get are R5.5, R6 and they got quite a few mainly greens, but it seems like a few more browns showing up later we get into the season. But keep in mind the thresholds there, you know, R6 we’re going double from 9 TO 18, R6.5 we can walk away from them. You know and had a few folks actually asked the field day was today over in Stuttgart, asking about red banded and honestly got a couple pictures of red banded like back around mid-June and I don't think I've gotten another one since. So I mean they're they're pretty light. I think the guys in northeast Louisiana are starting to fight them pretty good up there so maybe there's a chance some late beans, you know, in the state line that Lake Village, Eudora, Portland area, Montrose maybe, maybe they deal with a few of them, but really it looks like we're going to get out pretty clean there.

[06:40] Ben Thrash.

Guys are starting to pick up loopers down there, too.

[06:48] Nick Bateman

Yeah. And didn’t you say the ones you were seeing in your stuff the other day they were mainly green legged?

[06:54] Ben Thrash

Yeah, it looked like they were cabbage loopers for sure, but that you know, we start picking them up but usually not too long to we'll start picking up soybean loopers.

[07:03] Nick Bateman

And I guess time will tell whether, if not as hot and dry like this, a good chance maybe they can build on us. Some rain and nasty weather in like last week it may make them crash. Bollworm seems to be pretty thick in areas and some of these late beans but but generally fairly light. I mean I have had some calls on some 20, 25 on 25. So running one per sweep, but a lot of calls in the 3 to 4 range. Yeah. So you got any late beans that are starting to bloom, definitely need to be out there looking at them. For sure. 

[07:44] Ben Thrash

I guess there’s still a few, every once in a while have still been getting calls on army worms in beans like somebody mows a turn row or something, it seems like. And they, they move over into some beans along the edge of the field. So kind of keep that in mind. If you got a bunch of, you know, grassy turn rows and everything, you might just keep an eye. If there's some army worms out there that if somebody comes through, mows that or puts herbicide out on it, they do have a chance to move in over into those beans, especially those late planted beans is where I primarily seem to hear about them.

[08:18] Nick Bateman

The other thing too, from the soybeans standpoint, bean leaf beetles. You know, I've had a couple folks reach out this week with some weird pod feeding looking stuff that they knew wasn’t bollworms. And keep in mind that bean leaf beetles will kind of etch the outside of them pods, they don't necessarily get into the seed, but they’ll sort of feed on the outside. So I guess what I'm saying, if you're catching some low level, low to medium level light, mainly beetles out there, you're not seeing a lot of the defoliation, you might want to push that canopy back a little bit when you're sweeping and just kind of keep an eye on them pods to make sure they're not chewing on them too much. 

[08:56] Ben Thrash

Yeah, you can end up getting a little some secondary type infections in those pods, if they start doing a lot of that out there and they aren't the easiest things to kill either. If you got to go after them, you got to go with a tank mix of either something like Endigo or like a acephate, bifenthrin or something like that to actually get good control of them. They're you can't kill them with just a pyrethroid or really you can't do a good job with just acephate alone. Anyways, that's all I got Nick.

[09:32] Nick Bateman

Yeah. Yeah. It's still, still fairly quiet. I did have a couple folks asking about treating head worms in sorghum and trying to keep away from flaring those mites. Really your option there is Vantacor. Keep in mind, like Besiege is going to do a good job but that pyrethroid it might or might not flare, I said mites I meant aphids. So just keep that in mind. But it seems like sugarcane aphids relatively low this year.

[10:00] Ben Thrash

Yeah. Well yeah. So we got a few in our plots over at Mariana. We might put out a test or something tomorrow, but that's our real susceptible variety too. We're trying to get aphids, but well, if you need us. Cause my number is 501-517-3853.

[10:18] Nick Bateman

870-456-8486

[10:22] Ben Thrash

All right. Thank you very much.

[10:27] Intro/Outro

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