Summary of the 2022 Alabama Cotton Insect Situation

We certainly had some challenging situations through the cotton production season in Alabama in 2022. From severe drought in some areas, to excessive rainfall in others weather played a major role in the in-season management of the crop. Even so, we expect to have a very good cotton crop in 2022. We have heard several reports of 3 or more bales per acre being picked and expect our state average to be around 900 lbs. According to data from the USDA, Alabama planted just over 425,000 acres of cotton this year.

Overall, insects were not a major yield limiting factor for Alabama cotton in 2022. Many fields required multiple applications, as the statewide average was ≈5 applications per acre. However, thanks to proper scouting and the use of thresholds, the overall reduction of production caused by insects is estimated to only be 2.94%.

To start the season, grasshoppers required attention on many fields across Alabama, particularly on sandier, well drained soils and those under reduced or no-till strategies. No losses are expected from grasshopper feeding as insecticides applied at-burndown or at-planting are generally effective in controlling populations and preventing economic losses. For two seasons in a row, thrips pressure was higher in later planted cotton. Most of our cotton acres received foliar treatments to supplement at-plant insecticides (seed treatments or in-furrows). In many cases, the biggest concern around making foliar thrips sprays was the risk of flaring spider mites. In dry pockets, many farmers elected to use materials that are less harsh on beneficial insects, even at a slightly higher price point. Other pests such as slugs, snails or cutworms were observed and reported in a few fields, but rarely at economic levels during the early season.

Adult Tobacco Thrips

Spider Mite Injury

As the cotton crop began squaring in June, many fields across the state started dealing with two-spotted spider mites. In many cases, spider mites were worse in fields that received a thrips spray with a disruptive chemical, but that was not always the case. As we have shifted to reduced/no-till systems and started adopting more cover crops, early season spider mites have become a more consistent issue. This shift in combination with hot, dry weather can quickly cause a spider mite outbreak, even if everything has been done “right” in the field all season long. While losses to spider mites were low, some fields required multiple applications to keep populations from causing economic damage.

Another pest that farmers had to deal with during this time was the tarnished plant bug. Adult plant bugs infest cotton in June, at the on-set of pinhead squares. In general, plant bug pressure was lower in 2022 than in 2021. Many reports during the squaring season were that adult populations only required one application to maintain adequate square retention. In general, adult plant bug pressure was higher in earlier planted cotton, as these fields were the most attractive as adults were migrating from weedy hosts.

As cotton matured into the blooming window in July and August, the bug complex required most of the insect attention. Immature plant bugs, deposited as eggs by migrating adults in June, begin appearing around first bloom each year. In some areas of Alabama, this population was difficult to control, mostly due to issues complicated by weather. Insecticide wash-off was a major concern in areas of SW Alabama where rainfall was abundant. In addition to wash-off, many farmers were unable to apply plant growth regulators in a timely manner because fields were too wet to get sprayers in. This resulted in rank cotton, which is attractive to plant bugs and, in many cases, getting the insecticide to the plant bugs was difficult. Immature plant bugs prefer to feed on larger squares. When these squares are hidden down in the canopy, getting insecticide coverage is difficult, regardless of the choice of chemical, adequate control is rarely achieved in just one application. In these situations, and in other many areas of Alabama, plant bugs required multiple applications during the blooming window for control.

Immature Tarnished Plant Bug

Adult Green Stink Bug

The other player in the bug complex, stink bugs, are annually the most yield limiting insect pest in Alabama. This season, plant bugs were not as prevalent as normal. Based on observations in corn, we expected a much higher than usual stink bug season in cotton, as nearly all stink bugs that infest cotton turn over a generation in corn first. As corn began to silk, large populations of adult stink bugs were mating, and high numbers of egg masses were observed. However, the hot, dry conditions in June that hurt corn also appeared to harm stink bugs. The subsequent population that moved from corn to cotton was not as large as anticipated and many fields only required one application to manage this pest.

Other pests, such as aphids, silverleaf whiteflies and clouded plant bugs were observed in fields at low levels, but none were reported to reach treatment or economic levels. In general, the bollworm flight was relatively light, and our 2- and 3-gene cotton varieties provided very good control of bollworms and other caterpillar pests.

In summary, the Alabama Cotton Insect Situation was highly variable in the 60 counties cotton was produced in across the state in 2022. The situation changes from week to week and field to field, making scouting and monitoring critical for maximizing profitability. As we head into the winter, we will continue to evaluate insect management strategies to determine how we can tweak our system to effectively manage and keep losses to insects low.

Alabama Insect Situation: September 8, 2022

As the calendar turns to September, most of our cotton is past insects, some is beginning to receive defoliation applications, and all is hoping for a dry fall so we can get all the lint from the field to the basket. With the cotton season mostly behind us, the soybean insect situation is beginning to build.

VBC collected in 5 sweeps near Prattville, AL.

Over the past week, we have gotten several reports and phone calls about defoliating caterpillars in soybeans across central and northeast Alabama. While a complex of worms is in fields, soybean loopers (SBL) and velvetbean caterpillars (VBC) are the dominate and most important species in the mix. In addition to a detection technique (i.e., sweep-net or drop cloth), looking at the defoliation within the plant canopy can give an idea as to which species is doing most of the damage.

VBC: 4 pair of prolegs, defoliation begins in the upper portion of the canopy

SBL: 2 pair of prolegs, defoliation begins in the lower portion of the canopy

We have a couple of thresholds to use based on scouting technique for defoliating caterpillars. Prevent 20% defoliation during peak podfill (R1-R6), from R6 to R6.5 (≈7-10 days), prevent 30% defoliation. Alternatively, treat when 38 VBC or 19 SBL are found per 25 sweeps. As mentioned above, most fields will have a complex of worms, not just one or the other. Thus, detection techniques may be more useful for determining pest complex than treatment levels. Species composition is important for insecticide decisions. Another important reason for detection techniques is to get an idea of the size of the worms in the field. Like most things, VBCs and SBLs consume more food as they grow. In other words, larger worms eat more leaves (in a shorter amount of time) than smaller worms. If the majority of the population is made up of worms nearly an inch long or bigger, then action should be taken immediately. If most of the worms are small (less than 0.25 inch), then there is more time to make a spray.

Once the decision is made to treat, what are our options? There are several good materials to choose from, considerations for what to choose involve pest complex, economics and weather.

If soybean looper is the dominate pest, pyrethroids will do more harm than good. Our options for soybean loopers include diamides (e.g. Besiege, Vantacor, Elevest) or Intrepid/Intrepid Edge. These products provide good initial and residual control of the spectrum of the defoliating caterpillar complex. While the mentioned options provide excellent control of VBC, most labeled pyrethroids and IGRs also provide control. One issue with pyrethroids is the lack of residual control. We have seen instances in the past where multiple applications were required to manage VBC populations because of an extended migration over several weeks that would have likely been alleviated by a single initial application of a diamide.

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Cotton Insect Situation: August 26, 2022

Sunshine. That’s what the Alabama cotton crop across much of central and south Alabama is missing as of today. The 10-day forecast shows 50% or greater chances of rain across much of the state. As a lot of cotton is starting to open, we need to get out of this pattern. We realize that while insects are still in many fields, they do not pose the greatest risk to our crop at this time.  We have started seeing and hearing about some boll rot and hardlock going on in central Alabama and have seen a little bit of germination as well. Hopefully we get some sunshine and hot weather to dry all this cotton out and save as much of the lower bolls as we can.

With that in mind, we still have some fields with a ways to go and that need to be protected from insects. We are getting more calls on plant bugs than we are stink bugs right now, which is pretty unusual. Some things thoughts about insect management we enter the final push of the season.

Last effective bloom date: This is simply the day when you drop below at least a 50% chance for a white bloom to make it to the picker basket. Alabama is far too diverse to give a general LEBD, but most folks know how far out they can push a bloom and reasonably expect it to make it to the basket in their area.

With a given LEBD in mind, here are some key things to remember for insect controls:

Plant bugs can damage bolls until they are about 10-12 days old

Stink bugs can damage bolls until they are about 25 days old

Spider mites can cause reduced yields until harvestable bolls are     finished filling

Knowing we have stink bugs and plant bugs in some of these fields that need to be cleaned up, what are we going to do? Depending on your local weather pattern, I would avoid acephate at this point. While it is a very good bug material, it also has high wash off potential. We need a minimum of 8 hours with no rain, but really would prefer 12 or more. We are still hearing in some places that Bidrin is getting harder to find, hopefully we can still have that option. That leaves pyrethroids, primarily bifenthrin. We have heard reports of the past week about issues controlling plant bugs in south Alabama with pyrethroids. We could chase a lot of the issues back to several weeks prior when generics were used. In general, bifenthrin is the best “bug” pyrethroid we have. While the others are good on some other pests, we really would like bifenthrin better, particularly on plant bugs.

Another thought on late season insect management. Let’s try to get our “clean up” spray on before the cotton starts to fall over and cross rows with each other. While the sprayer tracks wont runover that much cotton, we would rather not runover any at all.

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Cotton Insect Situation: August 18, 2022

We are beginning to see some open bolls across south and central Alabama, the end is in sight. Not much has changed over the past week with our cotton insect situation. We are still fighting the bug complex in many fields across Alabama. In addition to tarnished plant bugs and stink bugs, we are also starting to observe some clouded plant bugs and leaf-footed bugs as well.

Cotton

SLWF

We are still in the early stages of the silverleaf whitefly (SLWF) situation in our areas with historic outbreaks (some parts of the Wiregrass). It is still not time to panic, but there are some fields infested that need to be watched.

Fields to be alert of include any of or a combination of the following:

• Late planted
• Drought stressed (hot, dry weather and/or dryland)
• Low beneficial insect populations (fields with recent insecticide applications)
• Hairy leaf varieties

Below is a copy of the SLWF handout from our colleagues who have a lot of experience fighting these critters at UGA.

SLWF Handout - Click to Enlarge

Bug Complex

Adult leaf-footed bug

While the presence of clouded plant bugs doesn’t necessarily change our insecticide recommendations, the presence of leaf-footed bugs would. In general, pyrethroids do not provide as good of control of leaf-footed bugs as the organophosphates do. That leaves us with 6 oz of Bidrin or 0.75 lbs of acephate. Due to the silverleaf whitefly (SLWF) situation in the historic SLWF areas (some parts of the Wiregrass), I would avoid Bidrin at this point and go with acephate. While we still don’t fully understand the reason, Bidrin really seems to exacerbate a SLWF infestation. In areas outside of this localized situation, Bidrin and acephate are both in play, depending on the availability of each.

Many of the people we have talked to have said they are getting ready to put out their “clean up shot” and walk away. Another season is beginning to wind down, but we need to keep scouting our later planted cotton and be prepared to protect bolls as needed.

Soybeans

Defoliating caterpillars (soybean loopers and velvetbean caterpillars) continue to build and require treatments in fields across central and south Alabama. We are watching traps closely in north Alabama to monitor when populations should be expected there as well. In addition to caterpillars, we are still fighting stink bugs, both the traditional species and the redbanded in many fields. Proper ID is critical or all of these species as concoctions to kill different species complexes may vary greatly.

Take Home Messages

While a fair amount of our cotton is out of the woods, we need to keep scouting in later fields and be prepared to take action when necessary. Be on the lookout for SLWF in areas with past experiences. Scout and properly ID which insects are in soybeans to make the most economic control options possible.

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Insect Situation: August 12, 2022

 Cotton

Not much has changed over the past week with the cotton situation. We are still fighting bugs in some fields statewide, while other fields are relatively clean. A little cotton is starting to open, while most of it isn’t quite out of the woods yet. We have talked to several folks that are starting to put out a “clean up” shot then walking away. Keep in mind that our stink bug threshold bumps up to 30-50% internal boll damage during the 7^th and 8^th weeks of bloom. This is because there aren’t as many susceptible bolls left in the field. They key thing to remember with stink bug management is that they can damage a boll until it is about 25 days old. So, we need to protect bolls we plan to harvest until the are at that point.

We continue to hear that the spider mite situation in the Wiregrass just won’t go away. Research from the mid-south says you can stop spraying spider mites at NSWF 5 + 350 heat units (likely somewhere around NWAF 2 or 3). Based on my experiences in the mid-south, and my short time working with cotton insects in Alabama, I think we need fight a little longer than “cutout” in the Wiregrass. In areas where the top crop plays a significant role in the yield potential of the crop, we need to protect from spider mites until we feel those bolls are filled. Spider mites damage cotton by sucking nutrients out of the leaves and can cause premature defoliation. In these situations, if we don’t get all the necessary photosynthate from the leaf to the boll, we will see yield losses. While it sounds like some control options are getting harder to locate, we do have several options (abamectin, Zeal, Portal or Oberon).

We are hearing reports of high flushes of bollworm moths in some fields across the state. We have also heard about some 2–3-day old worms found under bloom tags. To date, we have not heard of any issues with escaped worms in our 2-gene cotton (outside of 2017) or in our 3-gene cotton (at all). We also plant Bt sentinel plots across the state and se have not observed any issues with control in those plots either. We do not recommend treating bollworms based on eggs for this reason. We are paying a premium for these technologies so let’s give them a chance to work.

One final note on cotton, the silverleaf whitefly situation in Georgia is beginning to move west. We are hearing about fields being treated near the Alabama line and have received a report of SLWF in at least one field in Alabama. This will not be a widespread issue across the state but can have major impacts on cotton in the historic SLWF area. We will go into full details on SLWF as the situation evolves, but just to give a brief refresher:

·      Late planted cotton is at a greater risk

·      Threshold: 50% of leaves (5^th node from terminal) are infested with 5+ immatures per lea

        Immature SLWF resemble aphids, however if you rub the bottom of the leaf on your shirt SLWF will stay on the leaf and aphids will rub off

·         Insect growth regulators (Knack and Courier) are the backbone of SLWF management, but they must be applied timely (i.e. early)

Soybean

We are beginning to pick up looper and velvetbean caterpillar populations in fields. In some cases, defoliation is reaching 15-20% and treatments are going out. Scout to make sure you know which species are in the mix to make the proper insecticide selection. We have received reports of velvetbean caterpillars in fields in the TN Valley as well. We don't often get VBC that far north. We had several fields sprayed in 2020 but it had been quite a while prior to that. VBC are easily managed with most labeled insecticides, but they have every bit the damage potential as soybean looper and should be given the same attention.

The redbanded stink bug situation is still building as well. Once the immatures start to develop in fields, they can be difficult to get back under control. Two-way tank-mixtures of pyrethroids, acephate and/or neonics are necessary. If we come out swinging early, we can manage them. Things get difficult when populations build and are left unchecked too long.

Deer Survey

In response to a farmer request, the Alabama Extension Agronomics Crops Team is conducting a survey to better understand the impacts of deer population on crop production. Please take a few moments to help us collect information to try to use to figure out ways to mitigate deer losses in your row crops.

You can take the anonymous survey here (link).

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Insect Situation: August 5, 2022

The crop situation is all over the board in Alabama. Fields in the Gulf Coast region have received rains in something like 30 of the last 37 days, while fields in North and Southeast Alabama are rated as abnormally dry and in some cases, in a moderate drought (link). Thus far, cotton in Central and East Central Alabama looks really good. Retention has been high and after a slow start, rains have picked up and the crop is rolling.

Cotton

Dirty bloom with TPB nymph

As we have been discussing on the blog, the bug complex is what we need to be scouting for from this point forward. We have observed and have received reports that plant bugs are a little bigger player in the complex at this point in the year than we normally expect. We went to a cotton and corn field day at the research station at Fairhope yesterday (8/4) and plant bugs were the big topic. Scouts and consultants reported heavy numbers of plant bugs and dirty blooms in fields, particularly those around corn. Plant bugs have likely already moved out of corn, but heavy egg lay when they moved, combined with rains making getting into the field difficult and we have a situation where an imbedded population of plant bugs takes hold. We have seen similar situations in the TN Valley, although reports are that some fields are in good shape following applications over the past 10-14 days.

Overall, reports are coming in that the bug pressure is field to field in some areas. In other words, some fields have high pressure and other fields we aren’t seeing much. This drives home the importance of having someone looking and scouting to ensure we have economic infestations prior to making applications.

The spider mite situation in the Wiregrass seems to be continuing. Lack of rain and hot weather is exacerbating things. In these situations, we need to make sure we are scouting for other pests and only treating when needed, as automatic sprays may unnecessarily flare mites. If mites are in the field and stink bugs or plant bugs require attention, don’t hesitate to spray…but consider tank-mixing a miticide to help keep mites in check.

Soybeans

Our soybean looper traps in Central Alabama (near Tallassee) picked up this week. We collected nearly 500 moths over a 7-day period. It is time to start looking and thinking about SBL in Central and South AL. Keep in mind our thresholds are 19 SBL per 25 sweeps -OR- to avoid 20% defoliation until R6.5. We are also seeing a mix of green cloverworms (GCW) and velvetbean caterpillars (VBC) in the mix as well. In fact, as we were typing this blog (8/5), we received a report of economic infestations of VBC and defoliation in late planted beans in SW Alabama. Identification is critical, because GCW and VBC are easily controlled with pyrethroids or IGRs (Dimilin, Diamond), while SBL require a shift to the “newer” insecticides (Prevathon/Vantacor, Besiege, Elevest, Intrepid Edge, Blackhawk) due to resistance.

As our soybean crop continues to develop and fill pods, stink bugs are infesting fields. We are still getting calls about redbanded stink bugs, particularly in the Black Belt. Thus far, they have not made it to the TN Valley, and it is probably unlikely that they will…BUT never say never. In North Alabama, we need to be scouting for the traditional stink bug complex. Our threshold is 4 stink bugs per 25 sweeps. This is aggressive, but in a validation study we did last year, this threshold made us more money than a more relaxed threshold of 6 or 9 per 25 sweeps.

Deer Survey

In response to a farmer request, the Alabama Extension Agronomics Crops Team is conducting a survey to better understand the impacts of deer population on crop production. Please take a few moments to help us collect information to try to use to figure out ways to mitigate deer losses in your row crops.

You can take the anonymous survey here (link).

Take Home Points

Keep scouting fields, the situation is dynamic in Alabama’s cotton and soybean fields. “Boots on the ground” help us to get the highest return on investment for insecticide application decisions. Be prepared to treat when needed, but only when needed.

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Insect Situation: July 28, 2022

Cotton

Most of the reports we have received this week is that overall, we are in pretty good shape. However. There are some fields that are in need of reprieve. We have some fields in SW Alabama that cannot miss a rain, and other fields in N Alabama that cannot catch a rain. Cotton across much of central Alabama looks to be in good shape. We are hopeful for a good August and September so we can finish the crop out and maximize whatever yield potential we have in the field as of today.

Bug Complex

Not much has changed with the bug complex (plant bugs + stink bugs) situation over the past 7 days. Some fields are still requiring attention from plant bugs, but we are at the point with most of our cotton that we need to kill stink bugs when going across the field. We walked some fields today in S Alabama with a 2x threshold of both plant bugs and stink bugs. Many of these fields were missing lots of fruiting sites, but still have time to make a top crop if bugs are managed moving forward.

Our observations and reports have been that most fields sprayed over the past week to 10 days have not required follow up sprays. We typically expect to get about 2 weeks out of a stink bug spray before retreatment is necessary. This is not residual control, just typically about the time it takes another infestation of stink bugs to build to population levels that can cause economic damage (=10% internal damage). This may not be the case if sources of stink bug populations are nearby (corn, peanuts, pecans, etc.) and fields should still be monitored weekly to ensure damage is not building.

Spider Mites

Spider mite infestation in Headland, AL.

We have received reports that spider mites are requiring attention, primarily in the Wiregrass this week. Abamectin is typically the go-to for mites based on economics, but we wouldn’t normally recommend using abamectin as a follow up if retreatment is needed. There are pockets of resistance across the southern Cotton Belt and if abamectin doesn’t provide satisfactory control one week, I would not expect much to change the following week. We talked about alternative options in last week’s Blog (link).

Bollworm in cotton.

Bollworms

Thus far, the bollworm flight has seemed to be pretty low overall when looking at our trap counts across the state. Historically, the expected peak flight varies with South Alabama ≈July 10, Central AL ≈July 20 and North AL ≈August 1. However, we have received reports of egg lays varying from 1-10% in the TN Valley and high numbers of moths in fields in SE Alabama. In general, we do not recommend making insecticide applications based on eggs in Alabama, as we still rarely find escaped worms in our Bt cottons.

Peanuts

We are beginning to hear about infestations of defoliating caterpillars in peanut fields. Often, we have a complex of species including green cloverworms, soybean loopers, velvetbean caterpillars and some others such as fall armyworms, beet armyworms, bollworms, cutworms, or others. Our threshold is 4-8 worms per foot of row. The low end is advised when peanuts are small or stressed from other factors.

We also have received reports of lesser cornstalk borers (LCB) requiring treatment in the Wiregrass. This pest prefers fields with skippy stands and they thrive in hot, dry conditions. With the loss of chlorpyrifos (Lorsban), we only have a couple of options including chlorantraniliprole (Vantacor 1.2-2.5 oz), or chlorantraniliprole products pre-mixed with the pyrethroids bifenthrin (Elevest 5.6-9.6 oz) or lambda-cyhalothrin (Besiege 10 oz). Another option is the insect growth regulator Diamond (6-12 oz). Keep in mind that the weather conditions that LCB thrive in are the same the spider mites can blow up in as well. If spider mites are a concern, consider using products without the added pyrethroid as this may flare mites.

Deer Survey

In response to a farmer request, the Alabama Extension Agronomics Crops Team is conducting a survey to better understand the impacts of deer population on crop production. Please take a few moments to help us collect information to try to use to figure out ways to mitigate deer losses in your row crops.

You can take the anonymous survey here (link).

Take Home Points

Keep scouting and monitoring fields to know what insects are at what levels. In Alabama cotton, stink bugs will be the most yield limiting insect we face for the remainder of the season. Be ready to treat when thresholds are reached. 

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Insect Situation: July 22, 2022

Cotton

From this point forward, the bug complex of stink bugs and plant bugs will be the most yield limiting insect situation we deal with. Stink bugs will likely be the dominate pest complex, but we are receiving reports of plant bugs still requiring attention in some fields across Alabama.

Bug Complex

We spent a lot of time in cotton fields across the state this week and stink bugs and their damage were easy to find. We are still seeing plenty of brown stink bugs as well as a mix of southern green (C and S AL), green (N AL) and brown marmorated (both) stink bugs. For the most part, southern green (SGSB), green (GSB) and brown marmorated (BMSB) stink bugs are susceptible to pyrethroids and organophosphates, while brown stink bugs (BSB) are less susceptible to pyrethroids, although using higher rates increases control. While our thresholds are based on internal boll damage done by stink bugs, observing the species in the field can help determine what insecticide is needed for control. The pictures below show the different species and how to identify them.

BMSB - Note white bands around antenna
and abdomen.

GSB - Note black bands around antennae.

SGSB - Note red bands around antenna.

BSB - No bands around antenna.

  

Stink bug damage.

Other Pests

We are receiving reports of aphid populations crashing across Alabama. The fungus is beginning to take over and populations are decreasing. At this point, we probably don’t need to worry about aphids anymore. A few fields are being treated for spider mites in NE and NW Alabama, but overall, we haven’t heard much about mites over the past week. Based on the latest US Drought Monitor report for Alabama, some of these areas were abnormally dry to in a moderate drought as of July 19 (link). If you are in a dry area and mites are present, keep in mind that populations are easier to control when they are caught early. If the bug complex requires attention, look for spider mite injury and the presence of active populations. Consider mixing in a miticide if populations are active and growing. Options include abamectin (0.15 EC formulation = 12-16 oz, 0.7 EC formulation = 2.6-3.5 oz), Zeal, Portal or Oberon.

Soybeans

Populations of kudzu bug have exploded this year. We have been getting reports and have seen huge populations. In most cases, eggs are hatching, and nymphs are beginning to emerge. This is the prefect time to treat. Most labeled pyrethroids provide excellent control of kudzu bugs.

Adult kudzu bugs with eggs and hatchings.

The stink bug situation in soybeans seems to be fluid. Some fields have threshold levels (4/25 sweeps) while others do not. More fields in the Black Belt region are being treated for redbanded stink bugs. This is a pest that we need to be aware of in soybean fields in Central and South Alabama. Nymphs have begun to emerge, and embedded populations are building. At this point, tank-mixtures are needed to control adult and immature populations. High rates of bifenthrin (1 gal to 25-20 acres – or 5.12-6.4 oz) plus 0.5 to 0.75 lbs of acephate is the best option for controls. Keep in mind that there are label restrictions for these products in soybeans. Bifenthrin can only be applied once every 30 days, while a maximum of 1.5 lbs of acephate (a.i.) can be applied per season. Other tank-mix options include neonicotinoid insecticides (imidacloprid, Belay, Endigo, Leverage 360) at the highest labeled rates.

Deer Survey

In response to a farmer request, the Alabama Extension Agronomics Crops Team is conducting a survey to better understand the impacts of deer population on crop production. Please take a few moments to help us collect informtaion to try to use to figure out ways to mitigate deer losses in your row crops.

You can take the anonymous survey here (link).

Take Home Message

It is time to start thinking about stink bugs in cotton at the 3rd week of bloom or older. Our threshold is pretty low during peak bloom (weeks 3-6) at just 10% internal damage. Be prepared to treat when necessary. Our goal for 2022 is to minimize losses to insects as best we can.

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Cotton Insect Situation: July 14, 2022

We have gotten some much needed rains in some fields in parts of the state, while other are missing rains still. A lot of the cotton we have seen in central Alabama appears to have turned the corner over the past 7 days and is looking good. In the north, we have seen some fields that looked great and some that needed rain desperately. In conversations with most folks across Alabama, the situation depends on which field you are standing in and what day of the week you are in it.

Aphids in cotton

Aphids have been the big thing observed this week. We have made observations and received reports of pretty high aphid populations building across the state. The good news is that we have also received reports of the fungus being “among us” in South Alabama. We can’t predict exactly when it will spread statewide, but it is on the way. We don’t always see a yield response from spraying aphids, unless the cotton is already stressed by something else, like drought. However, one thing to consider is the difficulty of scouting for other insects when plants are heavily infested, and honeydew is all over the place. Finding immature plant bugs on a drop cloth with hundreds of aphids is no easy task either. While we don’t normally recommend making a special trip for aphids, if you are already going over the field for something like a PGR application, I would consider dropping in a high labeled rate of imidacloprid for aphids, assuming plant bugs aren’t at threshold levels.

Speaking of plant bugs, most of the reports we have been receiving are that populations are spotty and that in many cases, nymphs are still very small and just beginning to hatch. Depending on the age of the cotton and size of the plant bug population, we may can go out with a “plant bug material” like Transform (1.5-1.75 oz/A). If high populations of plant bugs are in the field, Transform is the best option for control. If the cotton is still around the first week of bloom, that is also a good time to consider a tank-mix of the insect growth regulator, Diamond (6oz). As the cotton matures into the 3^rd or 4^th week of bloom, however, we need to go with something that will also kill stink bugs. We are expecting a heavy stink bug year and have already begun hearing about stink bugs requiring attention in fields of south Alabama. One other comment on Diamond and plant bugs. There are two ways to maximize the effects of this material. Number 1: apply it at the first appearance of nymphs. This ensures that we don’t waste any residual “on the front end” and maximize the ≈2 weeks suppression out of it. Number 2: Don’t spray another chemical that would control plant bugs during the following ≈2 weeks. If we are so close to the stink bug window that an application will likely need to be made in the next week, we will not have needed the residual of Diamond as long. Just a couple of things to consider when looking at insecticide budgets for 2022.

If we want to control the “bug complex” (plant bugs + stink bugs) we really only have a few options. Acephate (0.75 lb), Bidrin (6 oz) or bifenthrin (6.4 oz). Although stink bugs prefer bolls that are 10-12 days old (about the diameter of a quarter), they will feed on smaller “thumb-sized” bolls if few quarter-sized bolls are available (during early bloom). Keep in mind our thresholds are dynamic and vary during the week of bloom (see picture). To sample, pull a minimum of 15-20 bolls that are 10-12 days old (about the size of a quarter) from the field (not all from the border) from at least 2 areas within the field. Bust the bolls open and look for warts, stained lint, or “pinprick” marks on the inside of the boll wall.

If you need to pick up aphids and control bugs, consider adding imidacloprid to the bug complex materials above. Transform is an excellent aphid material and would not need a tank-mix for aphids but tank-mixing a pyrethroid if some stink bugs are in the field would be beneficial.

One final note. In response to a farmer request, the Alabama Extension Agronomics Crops Team is conducting a survey to better understand the impacts of deer population on crop production. Please take a few moments to help us collect informtaion to try to use to figure out ways to mitigate deer losses in your row crops.

You can take the anonymous survey here (link).

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Insect Situation: July 7, 2022

Cotton Insect Situation

We have been in a lot of cotton this week and much of it has needed a good rain (or two). The storms we have been getting across Alabama seem to end up being isolated and for whatever reason, dumping rain in the same areas (and missing the same areas) during each event that occurs. I am no agronomist, but I suspect these dry fields will not be needing a lot of PGRs in the coming days. Those applications may need to wait to see how the crop responds to a rain. In some fields, cotton appears to be in “survival mode” and is sending resources to the small bolls in the lower portion of the canopy instead of going back to vegetative growth after a rain event. Again, I am not an agronomist, just what an entomologist seems to be observing.

Plant Bugs

The black drop cloth is the best way
to sample for immature plant bugs.

Based on our observations and reports we have received from across the state, it appears we may be in the “lull” between adult and immature plant bugs. The extended dry period we experienced seems to have caused more of a single migration period into fields instead of a “trickle” or prolonged migration like we observed last year. Many of the adult plant bugs that infested fields have either died from insecticide applications or appear to have run their course naturally. Sometimes, we see a lag time between this happening and immature plant bugs (nymphs) hatching out. We did a lot of drop cloth samples in our cotton that is around first true week of bloom in central AL and in the TN Valley. Our observation was that had we been sampling a day or two earlier, we would have found even fewer bugs. Most of the nymphs we found were first instars (hatchlings) that are very small. In other words, most of these plant bugs were likely just a day or so old.

Keep in mind that plant bug nymphs are extremely difficult to find in sweep-net samples and the black drop cloth is the most effective way to sample. If using a drop cloth, we recommend treatment when you find an average of 3 nymphs per 5 row feet (1 sample). Additionally, some people use a dirty square or dirty bloom threshold of 10% injury.

We are currently at a good time to get the insect growth regulator novaluron (Diamond) in the mix. This chemical kills nymphs as they molt from one instar to the next and is most effective when applied at the first appearance of nymphs, which is typically around 1^st bloom in Alabama. We usually recommend a 6 oz rate, which we feel provides about 2 weeks of residual suppression. Most times, Diamond should be tank-mixed with a knockdown insecticide such as Bidrin (5 oz), Transform (1.5-1.75 oz), Bifenthrin (5-6.4 oz) or acephate (0.5-0.75 lb ai). This can help control any remaining adults and larger nymphs that may already be in the field. At this point in the season (post-bloom), we no longer recommend the neonics (imidacloprid or Centric) due to resistance management, pollinator protection and lack of consistent performance on nymphs.

Aphids on a cotton square

Aphids

We have also started hearing about aphids building in some regions of Alabama. Normally, we don’t see much a yield response from spraying aphids in our research trials, but this year may be one where that trend doesn’t hold up. In fields that are already drought stressed, we do see yield hits from aphids compounding that stress. Treatment is sometimes recommended when populations exceed 50 or more aphids per leaf and honeydew is accumulating, especially under drought stress. We normally clean up aphids with plant bug sprays and don’t need to make applications targeted only for aphids. I know we have some (very) late cotton out there this year. If aphids are building and the cotton is drought stressed, I would consider an application.

Spider mites in cotton

Spider Mites

Spider mites are one of the most difficult cotton “insects” to make a management decision on. This is because thresholds are not well defined, and weather plays a significant role in population development. Our recommendation is to treat when 30-50% of the plants are showing symptoms, mites are present, and no rain is in the immediate forecast (see what I mean?). Of all insect management decisions, this one probably requires the most professional judgement. Products with the active ingredient abamectin provide relatively good control. Coverage is important for control and as the crop canopy develops, higher rates of these products are recommended. Remember that populations are often worse following applications of broad-spectrum insecticides but they can build in fields that have not been treated recently as well.

Peanut Insect Situation

TSWV Symptoms in peanuts

The phone has been relatively quiet on the peanut front this year. We are beginning our TSWV surveys with our REAs across the state and are observing symptoms ranging from 3-9% infection so far in the Wiregrass. Of course, there is nothing we can do at this point to reduce virus incidence.

The hot, dry weather means that we are at a risk of lesser cornstalk borers in out peanuts, particularly in dryland fields. Dr Mark Abney at UGA posted a good article on LCBs on the UGA Peanut Website (link).

Soybean Insect Situation

We are hearing about stink bug populations building in soybeans. Mostly, these calls have been in fields at or around the R3 stage and no seeds are at risk. Ordinarily, we don’t recommend treatment for stink bugs when there are no seeds at risk. However, IF redbanded stink bugs make up a large portion of the population, treatment may be beneficial. RBSB are not doing much economic injury at this point, but populations are difficult to control once they are established and immatures are present. Knocking them back early may help. This application would need to be weighed with the risk of flaring other pests, such as soybean loopers, later in the season. We don’t have any data on the risk vs reward of that early of an application for RBSB, just some experience on how damage RBSB can be and how difficult to control they can be as well.

If you would like to provide reports or observations on the insect situation from your region, please let us know. You can reach Scott Graham at 662-809-3368 or scottg@auburn.edu or Ron Smith at 334-332-9501 or smithrh@auburn.edu.

As always, if we can ever be of any help, please let us know.

Alabama Cotton Insect Situation: July 1, 2022

We have gotten some rains over the past week, although some of it was still isolated. Hopefully this will help kick the crop back in gear and get moving. We are starting to find more blooms, particularly in central and south Alabama, but we likely have some blooms in fields in the north as well.

Adult tarnished plant bug

Plant bugs are still the hottest ticket in town. Over the past few days, we have received reports of up 3-4x threshold populations in northeast (Cherokee Co.) and north central Alabama (Lawrence/Morgan Co.) and we have observed threshold populations in central Alabama and the Tennessee Valley as well. The common theme is older cotton and cotton that had not yet been sprayed for plant bugs. While fields that have been treated still have a plant bug here or there, we do not appear (as of yet) to be dealing with much re-
infestation of these fields. Reports out of the Wiregrass are that plant bug numbers appear to be relatively low. Some fields may have numbers and other do not. I spoke with our colleague across the line in Georgia, Dr. Phillip Roberts, he shared with me that while a lot of acres in central GA are being treated, folks are calling about low numbers in SW Georgia. So what we are hearing about in the Wiregrass (lower numbers) appears similar across state lines. We are hearing similar reports from the Southwest Alabama. The plant bug situation changes from field to field.

One thing to keep in mind is that plant bug pressure is often higher near field borders with corn. Corn is a good host for plant bugs. Typically, movement out of corn is expected around the time the silks begin to turn brown (R2 or the “blister” stage), but the movement could be before or after that stage depending on when the original egg lay occurred. Unlike with stink bugs, however, we do not recommend spraying corn for plant bugs. It just won’t help the corn (plant bugs are a non-pest), and plant bugs aren’t as “hemmed up” in corn like stink bugs.

In terms of treatment options, we still like the neonicotinoid products on migrating adult populations (imidacloprid or Centric). While these products, and particularly imidacloprid, won’t provide 100% control, they often provide enough to reduce populations below threshold and maintain square retention above 80%. As we get into bloom and start finding nymphs, we change from the neonics to chemistries like Transform, acephate, Bidrin or pyrethroids (depending on location in the state). Around 1^st bloom is also a good time to get Diamond in the mix. This insect growth regulator provides control of immature plant bugs and may be enough when combined with a knockdown insecticide to get us to the stink bug window (≈3^rd week of bloom).

Thumb-sized boll 
damaged by stink bugs.

Speaking of stink bugs, we are expecting this to be a heavy stink bug year. Our observations and reports from corn suggest high populations are out in the landscape currently. Although stink bugs prefer to feed on bolls about 10-12 days old (about an inch in diameter), they will feed on thumb-sized bolls if nothing else is around to feed on. The presence of stink bugs in early bloom cotton may influence plant bug material choices. Keep in mind our threshold for stink bugs during early bloom is 30-50% internal boll damage.

Even after the rains, we still have some spider mites in fields. Hopefully rains will knock back populations and let the cotton outrun them. Keep in mind that rain will not outright kill mites or eliminate them from a field. If you had some in fields prior to a rain, they can blow back up pretty quick if conditions allow. I am not sure that we have many fields that need to be treated for mites right now, but they are something to continue to monitor.

As always, if we can be of any help, please let us know.

Alabama Insect Situation: June 24, 2022

Cotton Situation

The past two weeks have been HOT and DRY across Alabama. We have gotten some scattered storms across the state, but we have also seen a couple of days in the triple digits and a good bit of our crop could use a good drink.

Blasted Square from TPB feeding

We have gotten reports from all cotton producing areas of Alabama this week and the biggest thing going is plant bugs. As more fields begin to square, more adult plant bugs are being found and more fields are needing to be treated. The good news is that most of the reports that we got this week was the fields that were treated the week prior did not have threshold levels of plant bugs this week and only “new” fields needed to be sprayed. Of course, we still need to check fields that have had an application because they can show back up. Our older cotton fields are beginning to bloom and will likely start to have immature plant bugs show up soon. We have not gotten any reports of this yet, but we know they are just around the corner.

With the beforementioned weather, we have the potential for the spider mite situation to “blow up” on us quick. One observation that has been reported from multiple regions of Alabama is that spider mites are worse in fields that were treated with acephate back during the thrips window. In some cases, this may have been as many as 3-4 weeks ago. That is not to say they can’t be found in fields treated with other chemistries or fields that weren’t treated for thrips, but make sure to look for mites in fields that were treated with acephate. With that being said, I would strongly consider the potential to flare spider mites when making a plant bug insecticide decision (note: not a spray decision, if plant bugs are at economic levels, we need to get them). In other words, choose a product that is less likely to aggravate mites.

Soybean Situation

Adult RBSB

We did some sweeps in R2 soybeans near Tallassee and found redbanded stink bugs. We were averaging about 2 adults per 25 sweeps (threshold = 4/25 sweeps). This is an unwelcomed but not unexpected find. We picked up RBSB this spring in clovers when we were sampling and the somewhat mild winter allowed for some survival. Normally, we don’t recommend a pyrethroid with an R3 fungicide trip, but I would consider a piggy pack application if adults are in the field. If we get behind on RBSB, it can be extremely difficult to get back ahead. They are likely not in every field and I would be surprised to see some in north Alabama right now, but now is the time to start looking in central and south Alabama if beans are in the reproductive stages.

As always, if we can be of any help, please let us know.