Insect Update from Lorenz, Bateman, and Thrash (7/8/21)

Extension entomologists Ben Thrash, Gus Lorenz, and Nick Bateman discuss plant bugs, spider mites, armyworms, rice water weevils, sorghum midge, and sugarcane aphids.

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Title: Insect Update from Lorenz, Bateman, and Thrash (7/8/21)

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

Ben Thrash: Welcome to Arkansas Row Crops Radio. My name is Ben Thrash, extension Entomologist for the University of Arkansas System Division of Agriculture. Today we’re going to give you a rundown on what’s happening in the insect world. I’m here with Nick Bateman and Gus.

Gus Lorenz: So I want to talk about cotton first. We’re getting a lot of calls about the plant bug situation and looks like it may be one of the worst plant bug years we’ve had in recent history. The numbers are extremely high out there and these adults are moving into the field in great numbers. I’m getting a lot of those calls where they sprayed 4 or 5 days ago and people indicate to me they got just as many as when they sprayed. That’s obviously a movement of plant bugs out of corn and wild host into the cotton field, they just keep coming right now. I would encourage you to get out and scout, particularly next to corn and wild host situations like levees and edges of fields, ditches, that kind of thing. Anything where there’s weeds are blooming, the yellow flowers, plains coreopsis are blooming right now. But we’re seeing a lot movement in the field right now, extremely high numbers and a lot of people have been forced to go to, you know we usually try to say transform until first bloom, but a lot of people hadn’t been able to do that this year on this pre-blooming cotton. I would encourage you to consider if the numbers are high, like if you’re seeing those kind of numbers, you may want to consider putting a little Diamond in the mix, 6 oz of Diamond and usually we do 2 shots, about 10 to 14 days apart when numbers are as high as they are, so something to consider. But if you have any questions or anything on cotton, don’t hesitate to give us a call. But the numbers are extremely high this year. And we’re seeing the square retention is being impacted. In some of our plots today that we looked at, numbers dropped well below 80% square retention on cotton that’s not even, we’re probably a week to ten days away from bloom and were seeing very, very high levels of plant bugs. Also, don’t expect to get a hundred percent control on anything that you use and the same can be said for this situation in mites. I’m getting a lot of calls about spider mite issues in cotton and it’s not restricted, again like plant bugs, to any one location. A lot of mite activity out there with this hot dry weather that we’re experiencing and when you make a mite application, I don’t care what the product is, whether it’s avamectin or zeal or portal, or whatever it might be, when you go back in four days, you can’t expect to see zero mites. It just doesn’t happen. And so what we generally see with a lot of these mites is, in four days it’s a little bit better than if you didn’t treat, at seven days it’s a little better than that, in a lot of cases it takes out to 10 to 14 days to see those numbers really decline but you’re going to see live aphids in the field after you treat and you have to be accustomed to that situation and not over react and make a second application before you give that initial application a chance to work. And that’s what most of the calls that we’re getting are in cotton right now and if you have any questions or comments on that don’t hesitate to give us a call if we can help you. My number’s 501-944-0942, and if you want to call Ben 501-517-3853. That’s 2 weeks in a row you remembered it. That’s pretty good. Nick, what’s your number? 870-456-8486. I guess, is there anything else. Our moth traps are extremely low right now, we’re not seeing hardly any bollworm activity out there. It’s really low. 

Ben: Not much going on in soybeans. A few stinkbugs here and there. We still have armyworms. If you’ve got grassy fields, check that grass before you make your herbicide application for armyworms on that grass, because once you spray it and that grass starts dying, they are going to move off onto your soybeans, so check that out. 

Gus: They’re still finding them in pastures too.

Ben: Yeah, lots in pastures. I got some calls today on that, so there’s a lot of army worms around. 

Gus: Really not a lot going on in soybeans.

Ben: Nick, what’s going on in rice?

Nick Bateman: Until we get to heading it, it’s kind of quiet right now. I mean there is some rice still going to flood where we need to watch out for weevils. As high as the pressure we’ve seen this year, there’s a chance some of this going to flood is going to catch that next generation coming out and get some pretty high numbers. Seeing a ton of rice stinkbugs up and down the ditches and roadsides and everywhere there’s heady native grasses, there’s’ a lot of potential there for this earliest rice that goes to head in the next week to ten days to have some extremely high numbers. 

Gus: Yeah, there’s a lot of rice stinkbugs out there and even in rice that’s not heading, we’re seeing rice stinkbugs out in the field like they’re sitting there waiting on the rice to start heading and I mean there’s a lot of activity on rice stinkbug this year. I think they might be pretty tough on us as this first rice starts heading.

Nick: Yeah, there’s a lot of potential there and we’ve been running ice age for the past month and a half. Right now we haven’t seen any issues with Lamda, that’s going to be our recommendation. 

Gus: So the seed treatment trials that we’re running through now with the rice water weevil numbers, the numbers are pretty high in a lot of cases.

Nick: Yeah, so in our checks, we’re pulling core samples so to put that in perspective the core is about 4 inches by 4 inches. Our checks are running anywhere from between 50 and 80 larvae per core, threshold is 3 to 4. So it’s running extremely high numbers. Even over in Stuttgart this year we were running 30 and we usually average 7 or 8 in our untreated so it’s extremely high across the whole state. 

Gus: And the seed treatments are holding pretty good?

Nick: The Demacor and the Fortenza looks great. In both their locations where there’s pine tree or Stuttgart with all the rainy weather it took us forever to get some Urea out and go to flood. In both cases we were 50 to 60 days after flood, we’re not seeing as much there with Cruiser and Nipsit as we would if we went to flood in a timely manner. It helped some. 

Gus: Anything else going on? 

Ben: Sorghum, a lot of sorghum.

Ben: Yeah grain sorghum, a lot of aphids around right now. A lot of people are starting to pick up aphids in their grain sorghum. And midge.

Gus: Midge seems to be worse this year than they have in the past few years. Of course we haven’t had a lot of grain sorghum acreage out there. It just seems like we’re getting a lot of calls people finding midge pretty frequently and in a lot of cases our threshold is one per head but I’m like, if I see one per 3 or 4 heads I get kind of antsy and I start getting a little concerned about it because they’re hard to scout for. But this sugarcane aphid, between the midge and the sugarcane aphid, we’ve got to be real careful. If we spray midge with a pyrethroid we’re going to blow that sugarcane aphid up and it doesn’t look like there’s a lot of Blackhawk out there which we have used in the past for midge control that’s worked real well for us. There’s not much else, Dimethoate, there’s not a lot of options there for midge control. And if you have to spray a pyrethroid, you’re opening the door to this sugarcane aphid problem and you have to be aware of what the potential problem is going to be, so on the aphid situation where our recommendations are pretty much Sivanto Prime and Transform and those are the 2 products that have performed the best for us and we did get us a label for the sweet sorghum this year. It’s fully labeled now, we don’t have to worry about 24 seed or anything like that. We have a label with Sivanto Prime for the sweet sorghum producers. That little bit of acreage we got out there it’s been devastating to those guys. This sugarcane aphid’s been really tough on them making sorghum but we do have a label for that now and they can use it. Is there anything else?

Nick: I think that pretty much covers it.

Gus: I think that’s pretty much everything we’ve got.

Ben: Alright, thanks for joining us on Arkansas Row Crops Radio.


End notes: 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.