Friday, August 12, 2022

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 7th and 8th 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 (5th 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.

Friday, August 5, 2022

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.

Thursday, July 28, 2022

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.

Friday, July 22, 2022

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.

Thursday, July 14, 2022

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 3rd or 4th 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.

Thursday, July 7, 2022

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 1st 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.

Friday, July 1, 2022

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 1st 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 (3rd 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.

Friday, June 24, 2022

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.

Thursday, June 16, 2022

Alabama Cotton Insect Situation: June 16th, 2022

We still have some thrips going in spots here and there, but we are mostly through that window. Plant bugs and spider mites are the biggest calls and reports that we are getting.

As more cotton is starting to square across the state, we are receiving more reports of adult plant bugs moving into fields. Remember our thresholds are 2 adults per 25 sweeps (8 in 100 sweeps) or 80% square retention in the upper 2 or 3 nodes of the plant.

One important thing keep in mind is that thresholds are more of a guideline than a hard and fast rule. The proper term is “economic threshold” which obviously means economics play a role (both commodity and input prices). Due to the fluctuation and variations of prices, we don’t change our thresholds each year, but we can adjust a little bit “on the fly” if we need to. With cotton prices hovering over a dollar, we can afford to be a little more aggressive with insect management. This is because even though the insects are “eating the same amount of cotton” they are eating “more money” because that cotton is worth more. This is not to say that scouting and thresholds aren’t important in years with high prices, an application with no insects in the field is still a waste, just that pulling the trigger a little sooner may provide a higher return. Of course, in years where prices are low, the opposite is true.

Early spider mite symptoms

We got some storms across Alabama yesterday, and that may help the spider mite situation a little bit, but I wouldn’t bet on it. With the temperatures across the state right now and projected to be even hotter next week, every insecticide application should consider spider mites. We are in a situation where they could blow up quick. I am not saying don’t treat plant bugs if you have economic infestations for fear of spider mites but try to choose something less likely to flare them. Our threshold is to treat when 30% or more of plants are infested with spider mites and damage is evident. Sometimes we may watch the forecast and see if an imminent rain can help us before we make an application. I am not sure I would do that with the current outlook. I think being a little more proactive on these building populations with upper 90’s and even into the 100’s temperatures impending would be prudent.

Mating southern green stink bugs in corn

I also want to briefly mention stink bugs. We have been in corn fields in central and SE Alabama this week collecting corn earworms for Bt resistance monitoring. There is currently a ton of adult stink bugs in corn fields that are mating, and some nymphs are beginning to emerge as well. Corn is the perfect trap crop for stink bugs and cotton. A well-timed application will help corn and cotton as well. The best time to spray is at tassel, while the ears are forming, but stink bugs can damage corn through the R2 (blister) stage. Most labeled pyrethroids provide good control. If you haven’t, consider making an application in corn, it will help that crop and likely relive some pressure in cotton later in the year as well. For more information on managing stink bugs in corn, watch this video (link) with Eddie McGriff and Dr. Katelyn Kesheimer.  

We will also give a reminder that we have two more scout schools (link) this coming week. We will be at the TN Valley REC in Belle Mina on Tuesday the 21st with registration starting at 8 and the program beginning at 8:30. We will also be in Centre at McCord’s Fire Station #1 on Thursday the 23rd. That program will begin at 10 am.

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

Monday, June 6, 2022

Alabama Cotton Insect Situation: June 6, 2022

Things were pretty quiet last week, but the Alabama Cotton Insect Situation seems to be picking back up this week. We have already gotten a few calls about threshold levels of adult plant bugs in squaring cotton in in Central and SW Alabama. If you remember last year, we had a big migration of adult plant bugs into cotton fields statewide around June the 15th. At this point, adults are moving into our oldest cotton (mid-April to first week of May) that is starting to put on squares. So, most of our fields aren’t at risk yet, but keying in on fields that are squaring is important. Much of the fleabane across the state has already or is starting to play out. This means plant bugs are looking for somewhere to go and a cotton field that is starting to square is a good place for them to settle in. Reports out of the TN Valley and NE Alabama are that not much cotton is squaring, and no threshold levels of plant bugs have  been observed.

Adult Tarnished Plant Bug
With input and cotton prices where they are, it’s going to be important to scout fields and be prepared to treat when necessary. Prior to bloom, our thresholds are 2 adult plant bugs per 25 sweeps or 80% square retention in the upper 2-3 nodes. One thing to keep in mind is that we may scout a field with high square retention, but also high numbers of plant bugs. That may mean that the bugs just moved into the field and that squares that were fed on haven’t yet had time to abort. That’s why we like to use these thresholds as an either/or and a both/and. In other words, if you hit one of the thresholds but not the other, we should go ahead and trigger a spray.

In terms of recommendations, we like to manage migrating adults as economically as possible, because there is always the potential for more to move in a few days after a spray. Unfortunately, nothing will provide much residual control of migrating adult plant bugs. I have heard some reports that some of our “June go-to’” products are hard to get. We have some options, such as imidacloprid (highest labeled rate), Centric (1.5-2oz), acephate (8-10oz) and depending on resistance in your region, bifenthrin (6.4oz). Keep in mind that per the label, Bidrin cannot be applied between pinhead square and first bloom.

Another thing to remember is that square retention is a good way to evaluate the efficacy of an insecticide on migrating adults. If you come back to a field 5 or 7 days after a spray and find as many or more plant bugs, good square retention will tell you your spray worked, and more bugs have moved into the field.

We should be through the thrips window for much of our cotton, some fields, particularly in north Alabama, may still need to be watched. As a general rule, we don’t see much value in spray cotton beyond the 4th true leaf stage, but we have seen some fields this year that would very likely benefit from a spray at the 5th or 6th leaf.

Early spider mite symptoms on leaves
The last thing I will mention is that we observed spider mites in a field in central Alabama today. It has been an interesting start to the season variable weather, most too dry and some too wet at times. These mites had likely been building on some weeds that were in the field and have moved into the cotton after a herbicide application went out. In dry areas, spider mites are another thing to consider when making insecticide application decisions. Hopefully the chances of rain across the state this week will materialize so we can get some reprieve and help get this cotton crop off and running.

The 63rd Alabama Cotton Scouting School is coming up. This year we have our 3 traditional locations: Tuesday, June 14th in Autaugaville, Wednesday June 15th in Headland and Tuesday, June 21st in Belle Mina. We will also have an in-season scouting update in Centre on June 23rd and a late season scouting update in Southeast Alabama in August. More information can be found here.

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

Tuesday, May 17, 2022

Alabama Cotton Insect Situation: May 17, 2022

Phone calls have started pick up over the past 7 to 10 days and grasshoppers and thrips tend to be the biggest insect issues we are hearing about. 

Grasshoppers are primarily a concern in reduced or no-till fields and in lighter, well-drained soils. Unfortunately, we don’t have any thresholds for grasshoppers as damage is sporadic and varies from field to field and year to year. The decision to treat is often based professional judgement or the level of risk a farmer is willing to take. At this point in the year, we are dealing with mixed populations and a fair number of adults in the field. The presence of adults (or winged grasshoppers) is important to note, because they are more difficult to control than the immatures (or wingless grasshoppers). Pyrethroids provide spotty control of adults and our general recommendation is up to 3/4 of a pound of acephate.

Most of the calls on thrips we have been getting revolve around making supplemental sprays in dry areas or in fields with historic spider mite issues. In these situations, we try to use insecticides that are less likely to flare mites, such as Intrepid Edge (3 oz/A) or Bidrin (3.2 oz/A). As far as thresholds, we recommend 1-2 adult thrips (dark brown or black) per plant with immatures present. The immatures are smaller and a yellowish color. Presence of immatures tells us that our at-plant insecticides aren’t providing control. You can sample by using a white Styrofoam cup (or something similar) and knocking plants into the cup then count the number of thrips found. Injury is characterized by crinkling of leaves. This is because thrips are feeding on new leaves still in the furl, which brings up an important point. When evaluating foliar sprays for thrips, often you cannot tell how good a spray did until the next true leaf has opened. In other words, if you spray cotton with one true leaf and the second still in the furl, the second may already be damaged, so the third true leaf would more likely show the protection from the spray. Cotton seedlings are most susceptible to thrips injury through the 4-5th true leaf stage and when not growing rapidly.


Late April planted cotton with no at-plant thrips treatment near Tallassee, AL in 2022.

Alabama is all over the board in terms of growing conditions and soil moisture. We have some fields that had enough moisture to germinate seeds but not enough to establish a stand, while we have also gotten several calls about slugs in soybeans. Storms seem to be so localized that its hard to say where we are and are not getting rains. Hopefully the weather will turn around soon and we can get some good growing conditions and kick the crop off.

As always, if we can ever be of any help, please don’t hesitate to reach out and lets us know. 

Friday, April 22, 2022

Cotton Thrips Models for Alabama in 2022 (April 22nd)

Generally speaking, Alabama cotton experienced higher than "normal" thrips pressure in later (mid-May+) planted cotton in 2021. According the Cotton Thrips Model (link), 2022 is setting up to be more of a "normal" year in central and south Alabama, with later planting cotton being at a higher risk in north Alabama. On April 21st, we ran the model for a project planting date of May 2nd across south, central and north Alabama. Predictions were fairly consistent across each region when moving east to west. Typically when we talk about risks from the model, we just mention one chart, showing the in-season risk for the given location. However, this year we also must talk about the chart giving predictions compared to previous years to best understand the big picture.

South Alabama

We ran models in south Alabama (Henry, Monroe, Escambia and Baldwin counties), and each model was nearly exactly the same. Thrips pressure in south Alabama is expected to be heavier in April through around the 2nd week of May. Below is the chart print out from Henry County, but remember it represents most of south Alabama.

In-season (top) risk of thrips injury in South Alabama in 2022. Comparison of 2022 vs previous 5 years (bottom) in the same area. (Chart showing Henry County, AL)

Central Alabama 

South of Birmingham

Models across central Alabama (Marengo, Autauga, Elmore, Lee counties) show the peak of thrips injury being in cotton planted in mid-April, with elevated risks through mid-May.

In-season (top) risk of thrips injury in South Central Alabama in 2022. Comparison of 2022 vs previous 5 years (bottom) in the same area. (Chart showing Autauga County, AL)

Birmingham and North

The model shows a different prediction for cotton in central Alabama beginning around the Birmingham latitude. Models in Pickens, Tuscaloosa, and Talladega counties show cotton planted through mid-May is at the highest risk, with elevated risk through the end of May.

In-season (top) risk of thrips injury in North Central Alabama in 2022. Comparison of 2022 vs previous 5 years (bottom) in the same area. (Chart showing Talladega County, AL)

Tennessee Valley and Northeast

Models in the Tennessee Valley (Limestone, Madison and Colbert counties) and northeast Alabama (Cherokee, Dekalb and Blount counties) were consistent and showed that overall thrips pressure is expected to be high across the regions. Cotton planted in May is at the highest risk of injury but earlier planted cotton is at a higher risk than in 2021.
In-season (top) risk of thrips injury in North Alabama in 2022. Comparison of 2022 vs previous 5 years (bottom) in the same area. (Chart showing Limestone County, AL)

Take Home Points

These models give us a good prediction of what thrips pressure may be this season and relative to other seasons. The model should not be used as a guide for when to plant, but rather what to expect when we do plant. By using the model, we can have a good idea for which fields may need a foliar spray to supplement seed treatments and which fields may not. The model predictions can change as unexpected weather events occur, so keep running them a couple of days before and after planting to make sure nothing has changed.

We will update the blog over the next couple of weeks to provide any changes that may happen.

Monday, March 21, 2022

Thinking About Thrips in 2022

Insect management is different from all other aspects of cotton production. With most insect pests, the situation changes year to year, week to week, and sometimes field to field. However, one insect that we can plan on being a consistent threat every year is thrips. This pest will infest 100% of the cotton planted in Alabama every year. What we cannot always predict, however, is when thrips pressure will peak. In a “normal” year in Alabama, we expect thrips pressure to be worse on early planted cotton and to be less later in the planting window as weather conditions improve. In 2021, this was not the case. Spring rains kept weedy hosts viable for a longer period, resulting in thrips pressure being the greatest on cotton planted after the middle of May. Much of our cotton was planted in this window and nearly 75% of our acres required a foliar treatment to supplement at-plant insecticides.

We have several options for at-plant management of thrips including insecticide seed treatments, and in-furrow liquid or granular materials. There are pro’s and cons of each approach, so deciding which strategy to use may make sense for one situation and not for another.


At-Plant Insecticide Options

Insecticide seed treatments
(ISTs) are currently the industry standard for thrips control, due primarily to the ease of application. However, under certain conditions control is variable. If conditions are not conducive to seedling growth, particularly if nighttime temperatures are cool, seed treatments alone may not provide adequate control. Due to developing resistance, particularly to thiamethoxam, we recommend seed be treated with an imidacloprid based seed treatment. There are several brand names, and some include additional insecticides, but imidacloprid should be a component. Under light to moderate thrips pressure, ISTs may provide adequate control. Seed could also be treated with acephate (e.g., Orthene) or acephate could be added to imidacloprid, however in most cases a bag of over-treated cottonseed cannot be returned if not planted.

Liquid or granular in-furrow insecticide applications are another at-plant option to manage thrips. These can be used to replace or supplement an IST. In many cases, in-furrow applications provide better control of thrips, however using them requires extra equipment, proper calibration and time when planting. Imidacloprid at the highest labeled rate has consistently provided good results in our trials across Alabama in recent years. Acephate has provided more sporadic control, likely due to the wet springs we have faced over the past 2 years and leaching out the chemical before the roots can uptake the needed amount to provide control. Aldicarb, now available as AgLogic15G, is another in-furrow option. This granular product provides excellent control of thrips and provides control of nematodes as well. Keep in mind that aldicarb is a restricted use pesticide and additional training may be required to use this product.

Foliar Insecticides

Foliar insecticides may be needed to supplement at-plant treatments. However, foliar applications should never replace an at-plant insecticide. Thrips can injure seedling cotton until around the 5th true leaf stage. Research shows that foliar applications are usually most effective when made at the 1st true leaf stage. The Thrips Infestation Predictor for Cotton is a reliable tool that predicts the relative risk of thrips injury for cotton planted at a given location and planting date. To maximize the accuracy of the model, it should be run for several days before and after planting, as unpredicted weather patterns may alter the prediction. This tool should not be used to determine planting dates, but rather to help plan out fields or planting dates for cotton that will likely need a supplemental foliar application. Several options are available to use to supplement at-plant insecticides.

·         Acephate (3 oz/A) is an effective and relatively inexpensive option, however it has the potential to flare secondary pests such as spider mites and is the least rainfast of the available recommended options.

·         Bidrin (3.2 oz/A) is another option that is effective and less likely to flare spider mites and is more rainfast than acephate, however it is more likely to cause crop injury when tank-mixed with herbicides.

·         Dimethoate (6.4 oz/A) is another cost effective and efficacious product with good rainfastness, however it is the most likely to cause crop injury when tank-mixed with herbicides.

·         Intrepid Edge (3 oz/A) is another effective option. Intrepid Edge is less likely to flare secondary pests but may need the addition of a surfactant to help with efficacy.

·         Pyrethroids are not effective and should not be used to manage thrips.

Effective thrips control is critical to get the 2022 crop off to a good start. When considering areas to cutback on costs, do not skip out on at-plant (IST or in-furrow) insecticides. We cannot manage thrips without having protection for the seedlings as soon as they emerge. If planting into cool, wet conditions, be prepared to make supplemental foliar sprays to help seed treatments get seedlings to the 5th true leaf stage. More information about thrips can be found in Pests of Alabama Cotton: Thrips (ANR-2718). For more information on thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide (IPM-0415). To stay up-to-date on the Alabama cotton insect situation, subscribe to the Alabama Cotton Shorts Newsletter, Alabama Crops Report Newsletter and Podcast, and the Syngenta Pest Patrol Hotline.