Midsouth Cotton: Pest Populations Rising — And It Hurts Worse After a Rough Start to Planting

    Tarnished plant bugs filling sweep net. Photo: Gus Lorenz, University of Arkansas

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    Laykyn Rainbolt, Contributing Editor

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

    OVERVIEW

    Plant bugs continue to increase, and bollworm populations are expected to rise soon as more corn hits brown silk. Plant bugs have been at treatment level in many areas for about two weeks and continue to require treatments. Stink bug populations are also rising, and redbanded stink bugs have been spotted in very low numbers.

    After a very wet spring, most areas could use a decent rain. The weather goes from one extreme to the other. Rain is in the forecast for this weekend (July 3), which is welcomed as irrigation is going on most crops.

    Fall armyworms continue to require applications, but most growers are seeing better control with suggested treatments and close observation of the armyworm’s origin.

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    CROP REPORTS

    Hank Jones, RHJ Ag Services, Winnsboro, Louisiana:

    “I found my first blooms today (June 29) in late-April planted cotton, but the bulk of my cotton is 10-leaf cotton. We’re looking at several new cotton varieties this year. In previous years, the bulk of our acres have been DeltaPine 1646. However, this year growers ventured into multiple new varieties. With new varieties, attention must be taken to assess how vigorous the plant is growing and how to Pix the fields.

    “Most of my older cotton has had a couple shots of Pix and has been sprayed a couple times for plant bugs. We’re getting Diamond out this week in a lot of the cotton prior to bloom. The retentions have been really good. We fought a few aphids, but it wasn’t anything abnormal.

    “The biggest thing in cotton right now is plant bugs. A lot of the corn is in brown silk and dent, so the plant bugs are really taking the express lane out of corn and into cotton. Fields will likely require weekly sprays, but some areas may even need tighter intervals than that to maintain yield potential and square retention. With the bulk of my cotton just getting into the pinhead square stages, plant bugs are really picking up. We may have to fight pretty hard in the pre-bloom stage to keep retention levels up.

    “The cotton feels about two weeks behind. Typically, the bulk of our cotton is blooming by July 1, but that won’t be the case this year. It will be another two weeks before we see blooms in the majority of our cotton.

    “The corn is entering the final stages. The bulk of the corn is in dent, and we are planning out the last few waterings based on the current soil moisture. The corn has had less disease pressure this year, and sprays for northern corn leaf blight are definitely down from 2020. A few scattered areas have experienced pollination issues in the corn.

    “Overall, I think we have a good but not great corn crop. With the current corn price, we have crop enough to come out pretty good. We’re rounding third base trying to take the corn to the home plate in terms of management.

    “Soybeans are a mixed bag. I have beans that are being eaten by fall armyworms (FAW) as we speak (June 29) all the way up to R4 and covered in pods. Hopefully we are on the tail end of a FAW flight that started last week. We’ve seen FAW in grain sorghum, rice and especially soybean fields with signalgrass or crabgrass that we killed. The armyworms moved from that grass to the small beans.

    “A few applications have gone out based on the number of FAW and the growth stage of the beans they’re in to assure we didn’t suffer any losses. We are still finding some armyworms in the beans planted in the last 10 days that are still trying to make a stand in more ‘pebbly’ dirt. The worms are finding spaces to get down to where the bean is sprouting. Again, most of those cases are fields that we sprayed grass in beforehand.

    “I know we are getting great control of FAW in fields we use products other than pyrethroids, but I haven’t heard of any pyrethroid misses. The tricky thing with armyworms is you can be clear on Friday and covered up by Monday when you check again. Armyworm is a very appropriate name for them because they show up in mass like an army would. Armyworm outbreaks take top priority because they can take over so quick. It creates a whirlwind for consultants, but they’ll be cycled out or dead by this time next week.

    “I’m picking up a few green stink bugs in my oldest beans. At this point, populations are just high enough to be aware they are out there. I did find my first redbanded stink bug north of I-20 last week (week of June 21), but it was flying solo apparently. We didn’t find anymore, but I expect to find more the closer we get to R5.5. Our oldest beans will reach that stage in the next couple of weeks.

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    “Bollworms haven’t been an issue yet, but I also expect them to pick up in the next couple weeks. A lot of our cotton is late. Bollworms typically go into the blooming cotton first, but we won’t have a lot of cotton blooming at the same time the soybeans will be blooming this year. I’m predicting what bollworms we do see in early July will be more so in soybeans rather than cotton.

    “We are a little behind where we would like to be going into July, but a large portion of our beans are starting to bloom. More and more fields are starting to be irrigated, and we are still working on cleaning up a few fields. Given the year we’ve had, we’re in the best shape we can be.

    “I expect to have some rice in early boot when I go check it tomorrow (June 30). Most of my rice is row rice, but I do have a little flooded rice. The flooded rice is younger, and we had to spray for armyworms when it was three-leaf rice. But a lot of the row rice is moving into the early boot stage. Overall, my row rice looks like it has higher potential than last year.

    “Last year, it was dry in May and June, so we had a hard time getting fertilizer incorporated evenly. However, this year we have had plenty of rain to assist with even fertilizer, so my rice looks better this year than it did in 2020.

    “On the other hand, we didn’t have many weeds last year because we were forced to start watering earlier, which caused pre-emergents to be activated great. But this year, we were late getting sprays out because it was so wet. I have more broadleaf weeds in most of my fields than normal. A lot of my row rice is intercropped very close to cotton and soybeans, and that has really limited the products we can safely use. We do have some pigweed and some other unexpected weeds we don’t typically see thanks to the flood.

    “There are hundreds, if not thousands, of rice stink bugs (RSB) waiting to jump on this rice from around the environment. When we sweep the field edges and ditches, we are finding higher RSB populations than we typically find at this point. I’m hopeful those just disappear, but we will more than likely have to be on top of that when the time comes.

    “I’m pleased with the rice and cotton. The beans do still have a long way to go, but we’re in good shape for what we’ve endured this year.

    “I have yet to find aphids in the milo I’m scouting this year. I can’t make heads or tails of that – we just seemingly have very low aphid pressure this year in milo.”

    Sebe Brown, Louisiana Extension Field Crops Entomologist: 

    “Cotton has been pretty quiet. I’m starting to get more reports of adult plant bugs migrating in good numbers especially adjacent to corn. A lot of our corn has hit brown silk, so we would expect the plant bugs to start moving over. Some are fighting an uphill battle because they just can’t get the plant bugs under control. Especially with the amount of corn we have across the state this year, this is not a novel fight. Various growers fight plant bugs this hard every year.

    “Some of our earliest cotton has blooms on it, but it’s a very limited amount across the state. Our latest cotton is still at the three or four-true leaf stage. It’s all over the board.

    “Although I haven’t heard of any bollworm issues yet, they could very well be coming soon. We have a lot of corn earworms in the corn right now that will be looking to move into the cotton or soybeans soon. The cotton that is blooming will be the most attractive. We don’t usually see bollworm movement into squaring cotton, but it can happen. Our crop is typically further along at this point in the year than it is, so it is not currently at the most attractive stage for this bollworm migration. Growers with late soybeans and grain sorghum should be prepared and start scouting for corn earworms from this flight.

    “I’m still getting calls about armyworms in beans, grain sorghum, rice and pastures. Tremendous armyworm flights are going on across the state right now. We’re getting 70 to 80 armyworms in 10 sweeps right now.

    “We are seeing some of the same issues Mississippi State saw with lack of control with pyrethroids particularly in rice and pastures here. This could be due to a mix of grass-strain and corn-strain armyworms. Things are starting to settle down, and guys are starting to get better control with pyrethroids even in areas where they know the armyworms are coming out of grass.

    “However, I have received reports of pyrethroid failures in rice in the northeast part of the state last week (week of June 21). Rice is a tough one because of the limited available products outside of pyrethroids. Dimilin is about the only option other than pyrethroids for rice, and a lot of guys are not confident in using pyrethroids right now because of the misses some are experiencing.

    “In soybeans, pyrethroids are working very well in fields where we know the armyworms are coming off grass. We’re having more problems in clean fields with no surrounding grass, which is the corn-strain. We’re recommending Dimilin, Diamond, Diamide, Intrepid or Intrepid Edge in those situations, and those are all working very well. You should be leery of using a pyrethroid because of the misses we’ve had, but no one talks about the success. The focus is always on the misses, and I think we’ve had fewer failures than what is circulating.

    “I’m hearing the same issues from grain sorghum, and product options are also very limited in grain sorghum especially when the worms are in the whorl. We don’t typically recommend treating for worms in the whorl (including fall armyworms), but I received photos from one grower where the sorghum was literally being eaten to the ground. It was the worst feeding by armyworms in grain sorghum I’ve ever seen, but that is not the norm. The few applications that have gone out have been in 6- to 8-inch grain sorghum that was being chewed to the ground, and those growers have been happy with the results.

    “Redbanded stink bugs (RBSB) are in the environment. We started picking them up last week (week of June 21), but we haven’t seen any threshold populations. I heard of the first spray two weeks ago in St. Mary Parish, which is about as far south as you can go. They were at a threshold population of RBSB that had to be sprayed, but we aren’t seeing huge numbers.

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    “We have beans here at R5 starting to put on pods. Out of 400 sweeps, we found two RBSBs. The numbers are still low. I think we will still have fewer numbers, but they are starting to come back. It’s about this time every year they start mating and laying eggs in the south and central regions of Louisiana, so we start seeing numbers rise slightly. In years like this, northern Louisiana, especially early planted fields, will often escape spraying for RBSBs or only have to spray once. The freeze really hurt them, but they’ve followed the path entomologists expected them to for the most part.”

    Tyson Raper, Cotton and Small Grain Specialist, University of Tennessee:  

    “The first couple weeks in June were absolutely terrible. The biggest issue wasn’t even too much moisture or the abnormally cool temperatures – those didn’t help. The biggest issue was it was so cloudy. We just did not have good growing conditions for the first 15 days in June. In the third week of June, we finally started seeing some sunlight, and things started to turn around.

    “It’s going to take time to make up for the growth we lost in the first two weeks of June, and now we’re dry. Scattered rain showers are coming down now (June 29), and tomorrow and Thursday have good rain chances in the forecast. But we really need a good, widespread rain to be ‘off to the races’ with this cotton.

    “Once we get that widespread rain, it’s going to be hard to Pix this crop after we’ve watched it struggle so much. A good opportunity to complete the Pix application will be at bloom or a little before bloom on strong acres. I would suggest against waiting until the second or third week of bloom as that is often too late to make a meaningful impact with reasonable rates.

    “Plant bugs numbers are increasing. Although we are not quite to threshold yet, I’m hearing numbers that make me think some fields will be needing applications for plant bugs by the fourth of July. It is crucial to maintain the thresholds with the right products this year. We can’t afford to let many of the first positions go in such a late crop like this.

    “We have some cotton moving into matchhead square, and I very much doubt any will be flowering by the fourth of July. We started planting around May 15, which is a little late for us, but the real killer was the late planting date followed by very poor growing conditions in the first two weeks of June.

    “We can all sing sad songs, but everyone around Tennessee I have talked to agrees this has been the worst start we’ve had in some time. The crop does still have decent potential, but we need rainfall now, timely pest applications and a long fall to mature out this crop.”

    Lee Rogers, Rogers Entomological Service, Steele, Missouri:  

    “Rain is in the forecast for today and tomorrow (July 1). It’s been hot and dry for a couple weeks, so everyone is ready for a good, general rain. Cotton, soybeans and corn are started on irrigation. It’s common for us to be rolling out polypipe by June 20, so this is right on track with previous years.

    “Our main two enemies in cotton are red spiders and plant bugs, and both are really increasing in numbers right now. We’ve been making applications for both for a couple weeks. Rain will knock back the red spiders, but once you have them, you pretty much have to deal with them all year. It’s important to knock them back when you can.

    “We seem to be off to a good year. We’re on time as of now, and the cotton crop looks good. I say on time, the cotton was planted earlier this year than the past two years, so I’m calling it on time. Everything was planted by around May 20. We are starting to Pix this week (week of June 28). Although I haven’t seen any blooms yet, some people will have blooms by the fourth of July.

    “A lot of the older soybeans are starting to bloom. We are starting to see a few stink bugs in the beans, but other pests aren’t at levels high enough to speak of.

    “The corn is about a week past tasseling, so we’re running with fungicides on it.

    “We still have a long way to go, but we’re just taking it week by week.”

    AgFax Midsouth 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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