Southeast Cotton: August Rings In Stink Bug Season

    Unopened cotton boll damaged from stink bug feeding.

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    Karli Stringer, Contributing Editor

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    Here is this week’s issue of AgFax Southeast Cotton, sponsored by the Southern Cotton Team of AMVAC.

    OVERVIEW

    The Southeast is increasing efforts to control stink bugs as populations increase. As the cotton matures, it is crucial to prevent damage as it directly affects yield potential.

    A multitude of other insects are finding homes in maturing cotton as corn dries up and weather conditions cause issues.

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    CROP REPORTS

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

    “Insect activity in cotton has increased this week. We caught more bollworms in our traps, so we’re still in the midst of a corn earworm flight, which turns into a bollworm once it ingests cotton. We are seeing quite a few caterpillars in non-Bt cotton.

    “Everything seems fine in our two- and three-gene cotton. I think the technology is holding up, and there are no breakthroughs to mention.

    “August is stink bug month, and we are seeing them around, but I haven’t had any nightmare stories yet. The third, fourth and fifth weeks of bloom are important for aggressively controlling stink bugs, and growers do a great job of that.

    “It’s raining again today (Aug. 3), so still no issues with spider mites. Cotton aphids are out of the picture, too.

    “In soybeans, we are seeing more soybean looper moths and larvae. I did see one commercial field that needed to be treated.

    “As the season progresses, we just need to keep an eye out for those and for corn earworms that turn to podworms in soybeans. The moths will lay eggs right where pods form, and the soybeans are definitely at risk with all of them flying around.”

    Jennifer Bearden, Extension Agricultural Agent, Okaloosa County, Florida:

    “Things are looking really good for our earlier planted cotton. They were able to get out there and get some spraying done. The later cotton is looking rougher, though. It’s mostly due to the fertilizer problems we’ve had. They just couldn’t get the fertilizer out when they needed to. I’m not sure if it will be able to catch up.

    “Now, we hope to keep progressing with the help of a normal rain pattern, but it’s looking like we can expect an exceptionally wet rest of the season.”

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    Ron Smith, Extension Entomologist, Auburn University:

    “There are a lot of little things to talk about. Our primary concern as we move into the remainder of the season is the bug complex. That includes tarnished plant bugs, both adult and immature though immature is more common now; clouded plant bugs; stink bugs, we’re now moving from brown to the southern green; brown marmorated stink bugs; and the leaf footed bug, which has similar boll damage as the stink bugs. Pretty much any field that hasn’t been treated has a mix of these insects. We’re beginning to get a lot of bolls at risk. Most of the cotton is setting bolls now. Fields that have been treated have hopefully gotten those pests below threshold.

    “We have not been able to stay on top of plant growth regulators because of all the wet weather. The field equipment just can’t get in and out of those fields, so a lot of the plants have a good bit of height. That means we have a very dense canopy, so when we spray, we have a difficult time getting the particles into the canopy where the bugs are feeding. Generally, the plant bugs are feeding on large squares or the white blooms, while the stink bugs are on the bolls that are about 10 days old. All that to say, we really need good canopy penetration. Some people ask if they can increase the water in the tank, but getting about 10 gallons can be a bit much. I would say instead try and increase the pressure. Either way, I think people should understand that because of this dense canopy, it may not be possible to zero out the bugs. You may go into a field right after a spray and still find bugs. It’s just a situation where, from now on, fields must be managed by day and week.

    “We have a wide spectrum of cotton – some of it looks really, really good and some of it was planted really late and is still really late. But the great-looking cotton has incredible yield potential.

    “I just want to stress it is really important the rest of the season, no matter what bug you are treating, there is a chemical in the tank that controls stink bugs. We must focus on that for the remainder of the season. They are already here in abundance and have been coming out of corn for weeks, and we expect there are still more to come. It appears we will have extremely high numbers to deal with this season. Growers need to understand when they damage older bolls, that damage is coming right off of yield potential. We don’t have time to compensate anymore.

    “We are also seeing some escape bollworms. We are right in the peak of a flight coming from corn. The two-gene cotton has some escape worms for sure, but they’re not at threshold as far as I know. I just want growers to know that pyrethroid may be necessary at some point.

    “I have one last thing to say, and it pertains to soybeans. We don’t really know how widespread it is, but our soybean looper traps have shown a high increase. Soybeans could be at an increased risk for looper moths in the coming days.”

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    Sally Taylor, Virginia Tech Extension Entomologist, Tidewater REC:

    “We still haven’t seen many bollworms — counts are low. Our main issue is really with plant bugs. We have growers trying to use pyrethroids alone or neonicotinoids alone and they are seeing very poor control. Now, it’s raining, and they’re upset because they can’t get it under control.”

    Phillip Roberts, Extension Entomologist, Tifton, Georgia:

    “Well, our cotton is all over the board. We have some cotton that looks excellent, and then we have some that is struggling with all this wet weather. Some fields have so much water and we can’t get in to do what we need to do. We need some sunshine and some open weather so farmers can get in there.

    “We do have a couple insects to mention. Just in the past seven to 10 days, we’ve seen an increase in corn earworm pheromone traps and an increase in moth activity in earworms. I just want to remind growers that Bt cotton is not immune to corn earworm. Of course, two-gene is at a higher risk than three-gene, but everyone needs to be scouting. There are not any widespread problems yet, but that’s why we need people out and scouting.

    “The other insect is stink bugs. It’s August and this is when we see numbers going up. It’s normal. We have a lot of confidence in our thresholds and in scouting, and growers do a great job of holding off damage. I want growers to pay attention to other pests in their fields. There could be corn earworm, white flies, spider mites, you name it. But when selecting treatments for stink bugs, they need to consider those other pests and make a decision that won’t flare them up.”

    AgFax Southeast Cotton is published by AgFax Media LLC
    Ernst Undesser, 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.

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