Cotton – Southeast – Mixed Pest Populations Making For Tough Decisions — AgFax

Photo: Justin Bellew

i
Pam Caraway, Contributing Editor

Owen Taylor, Editor

i
Here is this week’s issue of AgFax Southeast Cotton, sponsored by the Southern Cotton Team of Amvac Chemical Corporation.

OVERVIEW

Rain has boosted cotton’s potential across parts of the region in the last week. Some came from that last Atlantic hurricane. Dry areas remain, though, and the crop has taken a hit in drier locations. The immediate forecast, though, looks promising for a number of areas that need precipitation.

Mixed pest populations are making for tough decisions in parts of our coverage area. Treatment options aren’t always clear-cut when you need to treat one species but want to avoid flaring something else.

Dry and hot conditions are fueling whitefly and spider mite pressure.

Whiteflies remain the driving factor in Georgia this week. See comments by Phillip Roberts.

Stinkbugs are mostly light, based on this week’s reports. Bollworm moths are active in parts of the region and it’s possible to find eggs in places, but no widescale infestations are afoot.

Plant bug treatments continue in some areas. Those applications also are picking up any stinkbugs in the picture.

i

CROP REPORTS

David Butcher, NC Ag Service, Inc., Pantego, North Carolina

“The storm (Hurricane Isaias) blew over some cotton and corn, but the rain was needed. In our area, it probably was more beneficial than detrimental. We’re getting a little rain all along now.

“We over-sprayed two-gene cotton for bollworm. We haven’t seen any bollworms in the three-gene cotton. I’m not even finding indications of feeding.

“Because this crop is a little later, we could still see heavier insect pressure in the fall. Our biggest insect issue so far in cotton has been plant bugs, but that threat is pretty much behind us now.

“With the rain, crops look better. Cotton maturity is catching up. Corn varies. The early corn will generally be okay, but the weather was just too hot and dry at pollination in the later-planted corn.

“As is typical, we are spraying later-planted soybeans for corn earworm. We don’t often have worm trouble with early beans, and that held true this year, too.”

 

Chad Savery, Anchor Ag Solutions LLC, Fairhope, Alabama

“We have a mixed bag of insect and disease issues in cotton.

“Plant bugs are persisting, and a new generation has developed in about 25% of the fields. Every cotton acre was treated for stinkbugs, some a second time. We sprayed one field for spider mites. We don’t have any aphids.

“Normally, we’d be seeing leaffooted bugs about now, but they haven’t turned up. The moth flight is past, and bollworm wasn’t a problem at all. We didn’t spray any cotton for them.

“On the disease side, target spot is ripping pretty good in a few fields, even after treatment. We deal with target spot every year, but it’s still a mystery. One field has bacterial blight, but pressure overall is lower than normal. We have less cotton leafroll dwarf virus than we’ve had in recent years.

“The crop is slowing down, but we still need to fill bolls. The majority of our acres are between the fourth and seventh week of bloom and we’re at about 23 to 24 nodes. A few fields are suffering for moisture, but most of our acres are holding up well. But we will need more rain to fill out this crop.

“In peanuts, we are starting to see occasional white mold hits. Leaf spots aren’t bad so far. Tomato spotted wilt virus is sporadically heavy. Insect and worm pressure are low. Overall, our peanuts have good potential.”

 

Richard Davis, Davis Ag Consulting Co., Inc., Montgomery, Alabama

“Some of our old cotton is cutting out. I saw a couple of open bolls last week. Most of my cotton is dryland, and irrigation definitely paid off this year. This heat is taking a toll. Rain is in the forecast for later this week, which will help cool canopy temperatures and help us mature these bolls. We have a decent crop set. If we can fill them out, we’ll be okay.

i

“Most of my cotton is two-gene, but we haven’t had any trouble with bollworms. If I look hard enough, I can find damage on a boll or two every now and then. I found two fall armyworms, but haven’t yet seen any bollworms.

“Overall, insect pressure is low. I haven’t sprayed anything for stinkbugs yet. We did spray for plant bugs and we treated 50 or 60 acres for spider mites. With the mites, it was pretty much an edge effect.

“We don’t have any whiteflies. I have never had whiteflies in this area, and I’m hoping that holds true for this year, too.”

 

Sally Taylor, Virginia Tech Extension Entomologist, Tidewater REC

“We are getting a lot of calls about worms in peanut, but few concerning worms in cotton. We are still below the 6% injury threshold for bollworm in conventional and two-gene cotton varieties. Plant bugs have been spotty all season and numbers are spiking this week. This ranges from heavily infested fields to fields with little or no bugs.

“I can’t over-stress the importance of scouting. Use a beat cloth to sample multiple parts of the field. Let me know if you need one or need help learning how to use it.

“Scout soybeans, too. We don’t want large worms developing when plants have pods. Threecornered alfalfa leaf hopper caused injury in multiple counties in south-central Virginia. This injury happens early in the season and leads to lodging, which is showing up now. Use restraint if considering spraying leaf hoppers at this point.

“Soybean loopers are here early and are mostly pyrethroid-resistant, and populations can explode following a spray. If you have unexplained lodging in your soybean, please reach out to my program. I want to know the distribution of the problem so we can predict at-risk fields next season.

“Predictably, we have fall armyworm pressure in forage corn in the western part of the state. Avoid single-gene Bt hybrids in late-planted corn.

“Sugarcane aphid is finding sorghum no matter where it is, no matter how small the field.”

 

Jack Royal, Royal’s Agricultural Consulting Co., Inc., Leary, Georgia

“We are hot and dry. All I can say is thank god for irrigation. We just need a widespread general rain to help drop these temperatures.

“We haven’t had much of a bollworm flight, so we aren’t spraying any fields for worms, but we are treating some cotton for stinkbugs. We sprayed all the cotton once for stinkbugs and came back a second time over less than 10% of the acreage.

“We have a few whiteflies, but nothing at threshold. We are monitoring closely, but we’ve been able to keep them down with crop management.

“We sprayed less than 5% of our peanut fields for foliage feeders, but numbers started going up over the last 10 days. Where worms went over threshold and reached about 3.5 worms per foot, we added a diamide to our fungicide application. No telling what we’ll see the rest of this week.

“We are staying on a good fungicide schedule in peanuts. With this heat and the irrigation situation, you can create the prime environment for white mold, and my goal is to never see white mold in any field. With the fungicide schedule that most of my growers stay on, we haven’t detected any disease so far. We spend the money so we don’t have a problem.”

 

Dominic Reisig, NCSU Extension Specialist, Entomology, Plymouth, North Carolina

“We received plenty of rain from the storm (Hurricane Isiais) that came through. Western North Carolina needed rain, but the east may not have needed it as much. Our crops mostly look good, although we’re in a wet pattern now and some fields need draining.

“Insect activity is spotty. We have spots of plant bugs, stinkbugs and bollworms. The moth flight is super heavy in various areas, but we don’t see widespread issues in the field. Spider mites are only an issue if you deplete beneficial insect populations.

“We definitely are spraying soybeans for worms. Here and there we also are treating stinkbugs. Nothing is widespread.”

 

Ron Smith, Extension Entomologist, Auburn University

“We have a bit of everything scattered all over the state, and some of each is being treated. We don’t have one insect or worm to single out. Everything is just scattered everywhere.

“We’ve got a relatively heavy bollworm moth flight in the Tennessee Valley, but we haven’t heard of any economic numbers of escaped worms. We have some old escaped worms in the Prattville area that are about to cycle out.

“Stinkbugs are showing up at damaging levels, and we still have plant bugs – tarnished and clouded – hanging on. Leaffooted bugs and spider mites are causing problems in a number of places in the state.

“Silverleaf whitefly is localized. We are going back to scout whitefly in the traditional areas later this week. If it stays hot and dry, whitefly is probably going to spread.

“We have bolls opening. On one stalk of cotton planted March 18, I have 10 open bolls and one cracking. Our older cotton had about three good weeks of boll setting in July. It needed four weeks.

“In soybeans, green cloverworm and velvetbean caterpillar are causing problems in the southern part of the state. Soybean looper populations are in low numbers but will probably go up in the next week.

“Overriding all of that, we need widespread rain. Where it hasn’t rained in two-plus weeks we are terribly dry, and are losing yield potential. Late-planted cotton historically is at greater risk of dry weather, and you can’t make much cotton if it doesn’t rain. Even if we don’t set more bolls, we need rain to fill out the bolls we do have. The outlook is good for scattered thunderstorms this week.”

 

Jeremy Greene, Clemson University, Entomologist, Blackville, South Carolina

“We are getting some rain. We still have scattered storms, but they’re bigger and going across more fields than not. Overall, we’re better as far as moisture goes.

“The downside of this rain, at least locally, is the moisture encouraged the emergence of corn earworms from pupae in the soil, and we’re seeing more moths. The rain also has made cotton more attractive.

“We likely won’t see the result of egg laying for a week or so, but they certainly have time to complete their life cycle. We will likely see another push from bollworms before the season ends.

“Aphids started building again in one area. At this point, we shouldn’t do anything but watch them.  We need to be more concerned about bollworm – if the field is planted to two-gene cotton. If it’s three-gene cotton, we probably don’t need to worry too much about bollworm.

“But, keep looking for bollworms. Activity in my trial plots is higher than it’s been in years.

i

“Stinkbugs are right on time. August is stinkbug month. We need to pay attention to which week of bloom each field is in and make decisions based on the dynamic boll-injury threshold.

“Soybean looper activity picked up a bit in soybeans. We still have a mix of green cloverleaf worms, podworms and velvetbean caterpillars. Stink bugs are very active in soybeans with developing pods.

 

Phillip Roberts, Extension Entomologist, Tifton, Georgia

“It rains somewhere nearly every afternoon. It just depends on who gets it.

“Silverleaf whitefly (SLWF) continues to spread. It’s not a bad problem everywhere. Where all of our growers are working together, they all benefit. That includes making good decisions and treating every acre at threshold.

“The rain helps a bit with managing SLWF, but what we need is a general rain across a broad area. Thunderstorms definitely help if you only have a few SLWF. A thunderstorm gives us a break when we have a population of whitefly that is absolutely entrenched in a field and we’re treating with insecticides.

“In some localized areas we are seeing really high migration of adult SLWF from areas that have been infested for a few weeks. When we witness this massive migration into a field we need to use contact, systemic products.

“In some situations where an insect growth regulator (IGR) was used on time, heavy migrations moved in following that application. In a case like that, we may need to come back with a contact, systemic material, and then follow up with another IGR.

“Growers on the fringe of the historic whitefly areas may be able to hold off on treatment if they’re just now seeing a few adult SLWF. Scout and use thresholds.

“If you haven’t seen whiteflies yet, you’re probably going to make it. If you started seeing whiteflies two weeks ago, you likely will have to deal with them.

“Where possible, delay other treatments and hold onto beneficial insect populations for as long as possible. With that approach, we may be able to beat them to the finish line. Cotton planted in June is more likely to be under pressure. Early-planted cotton is likely going to make it.

“That said, we must treat whiteflies on time. Being a week late on management is going to cost you money. We can’t wish them away, but we are going to be alright. We just need to take this situation seriously.

“The good news is stinkbug pressure is mostly low. If stinkbugs are below threshold, focus on whiteflies. Again, trust your scouting.

“Corn earworm numbers are still highly variable. However, I talked to a consultant this week who had to treat some fields. We know corn earworm is not as susceptible to the two-gene Bt cottons compared to what they used to be. Pay attention and be prepared to react.

“One grower couldn’t be timely and sprayed a week late, and he’s going to pay for that. Sometimes we just take for granted how good the Bt technology is, but we must remember that yield losses from bollworm can happen here.

“Spider mites may have settled down a bit, but they are still around. Rain makes the cotton look better, but it doesn’t wash away mites like it did years ago.

“Other than SLWF, we are in really good shape. And whitefly isn’t everywhere. Where it’s raining or we have irrigation, I’m still optimistic about the crop.”

 

Steve Brown, Extension Cotton Specialist, Auburn University

“The crop has advanced rapidly in the last few weeks. Many April and early May plantings are showing signs of maturity as the crop blooms in the upper canopy, leaves decline with age and leaf spots, and large bolls begin to speckle and harden.

“This week’s forecast has good probabilities for rain in the entire state, so most fields likely will get some much-needed relief. If we had a broad inch or so of rain each of the last couple of weeks, we might not have been able to gin all the cotton we would have made.

“We do have a good crop. In places, it’s exceptional. In other areas, heat and drought have diminished it somewhat.”

AgFax Southeast Cotton is published by AgFax Media LLC
Owen Taylor, Editorial Director.
 
Working-Copy%5B1%5D.jpgThis weekly report is distributed during the cotton production season. It is available to United States residents engaged in cotton farming, field scouting and other qualifying ag professions. Mailing address: 142 Westlake Drive, Brandon, MS 39047. Office: 601-992-9488.
©2020 AgFax Media LLC




The Latest


Send press releases to Ernst@Agfax.com.

View All Events


Send press releases to Ernst@Agfax.com.

View All Events