Entomology Update: Spider Mites in Cotton, Loopers in Soybean, and Rice Stink Bug

In this week's Entomology Update, Extension Entomologists Ben Thrash and Nick Bateman discuss termination timings for soybean and cotton, spider mites, loopers, rice 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 24th and there's not just a whole lot happening out there, kind of winding down the year, but we got a little bit talk about. What's happening in rice, Nick?

[00:22] Nick Bateman

Yeah, I actually had several phone calls this week on a bunch of this green rice getting stink bugs in it and fairly high numbers, a lot of it's treatable levels and numbers. You know we talked about earlier in the year if you use Endigo or Tenchu to treat it, you know as long as you're not exceeding somewhere between 12-15 there that first two weeks of heading, try to hold until those head start turning down so that you can make it through end of the season with it. Some of the numbers we’re hearing right now you're going to have to treat earlier than that but some of the other questions we're getting some of these really late fields that got planted that that they had a very mixed bag of emergence on. We got rice out there that’s at soft dough and you got rice out there that’s at late boot. You know where the field’s 50/50 due to just weird emergence there and high stink bug numbers. I understand in the whole field’s not 100% headed, but I believe those situations need to protect that stuff that’s at soft dough. But you might be setting yourself up for two applications. In that case, we're only labeled for one of Endigo this year. You could try to follow it up with Tenchu or vice versa. Lambda has looked a little bit better this year than it has the past couple, but I still don’t think it’s reliable but that's pretty much it from a rice stink bug, rice stand point.

[01:52] Ben Thrash

Yeah and in cotton you know we're kinda terminating a lot of our insecticide applications now we're past the last effective bloom date for all the state you know and I've been getting some questions on spider mites and you know after this I think that cool weather we had that rainy spell kind of knocked a bunch of out. You know if I look at some of my stuff down at Mariana where I got some spider mites, it looked like they got some fungus that killed a bunch of them. And then, so we probably got some help there, but it kind of seems like some of those populations are rebounding from this hot, dry weather that we've had over the past, you know, couple of weeks. So, some guys are having some questions about that. And, you know, there's across the Mid-South it seems like we've got a little different recommendations on termination timings for spider mites, you know, 650 heat units passed cut out is kind of I guess the most recommended cut out for spider mites. But if I had a bad spider mite population and I was at 650 heat units and I still needed, you know, to not had my plants prematurely, the defoliated, I'd probably still spray them around that if they were bad enough. If it looked like that population was going to go out of control and you know prematurely defoliate your cotton, you might still have to treat them a little bit that's really the point of that is just to keep that cotton from being prematurely defoliated or reducing the photosynthetic capacity of those plants down to where those bolls aren't not finished filling out. So just keep that in mind. One thing that probably a lot of fields you might still have to keep an eye on are stink bugs. I think the thresholds 20% damage bolls or like one per five-row feet, one stink bug per five-row feet. You still need to treat so remember cut out for them or termination timing for them’s 450 heat unit passed cut out. I guess move on soybeans. There's a pretty decent number of loopers around that. It seems like more and more people are starting to pick them up now. I'm getting phone calls on them and just remember, Intrepid in my trials so far has not looked very good. So I would stay away from the regular old methoxyfenozide. Go with something like Denim or Intrepid Edge are the two products that are out there, and that's probably what I'd run. Stay away from the diamides. The diamides, Besiege do not look good on soybean loopers this year. So I’d stay away from those products. But another question we’d been getting has been what I do if I got stink bugs and looper, what's my cheap option? These beans are, you know, close to R6. I don't have that much time left on them. What's my cheapest option there? And I'd say it kind of depends. I mean, I would run either and you still got to run Denim or Intrepid Edge if you got loopers those are your two options for loopers and then you know if you got stink bugs green stink bugs at a not extremely high population, I’d just run lambda a gallon to 35 on the 1 pound stuff. Or if you're going with like a Warrior II do a gallon to 70 on the 2 pound stuff, that does a really good job. But if you got browns out there, I'd recommend running an acephate. Or bifenthrin. Acephate tends to be a little better. That's why it would be my go to. But you know, it's you got some bifenthrin laying around that does pretty good job too. So that's kind of what I go with. But you heard anything on army worms, Nick?

[06:19] Nick Bateman

I actually got several texts this week about seeing them on turn rows and stuff. Not really hearing about them in any crops, per say, but there does sound like there's pretty good population on some turn rows. I don’t know if it’s ultimately going to end up affecting us this year or not.

[06:35] Ben Thrash

Yeah. And I got a call from Kelly Loftin, who's does a lot of our pasture stuff. And he said down in South Arkansas, they had started picking some and some pastures and pretty good numbers. So they'll probably end up making their way up north. So if you got any pasture or anything that you're looking at, you might keep an eye out for them. And, you know, a lot of people probably won't want to spray a bunch of burned up grass, it looks like right now. But, you know, there's hot, dry conditions. With the soybean, though, it might keep on the soybean looper, population might keep dragging out. You know, there's a little cool weather and maybe a little bit of rain in the forecast from what I've seen, maybe Monday. But I don't know if it's going to be enough to do anything or not for the soybean loopers. 

[7:27] Nick Bateman

Time will tell.

[7:28] Ben Thrash

Yeah, but anyways, that's all I got. So if need us, call us my number’s 5015173853.

[07:38] Nick Bateman

Mine’s 8704568486

[7:41] Ben Thrash

Alright, thank you.

[07:42] 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.