Heavy Plant Bug Season May be Becoming a Reality

Last week, aphids began to build in spots in fields statewide. Ordinarily, I would recommend to let the natural fungus take out the aphids. However, each field and season presents a different picture. The fungus always works, however sometimes it is a week to 10 days later than we would like. Since we have a lot of late maturing cotton this season, I don’t feel we need to let aphids set our cotton back any further. Even if aphids do not cause yield losses, when an entire field is drooped down from aphid stress, we are likely seeing some maturity delay. For this reason, in 2018, I am suggesting that if a grower is going over a field for weed control or PGR application, then I would add an aphid control insecticide in the spray. We have some very economical choices for aphid control when they can be piggy backed with a trip over the field for another purpose.

Now on to plant bugs – I say plant bugs because we could easily have both the tarnished and the clouded species in some fields. In fact, I picked up some clouded species in sweeps in cotton last week in central AL. Historically, we have had more clouded in wet springs. Maybe because we get a better growth on button bush, a wild host for clouded in wet seasons. Button bush is a plant that likes low, swampy habitat, and excessive rainfall gives us that. No matter whether it is TPB or CPB, our scouting thresholds and controls are the same.

Now let’s talk about the TPB. The rainfall in the past month has kept their primary wild host, daisy fleabane, fresh and it appears that 2 generations have developed on fleabane. In mid May, we had mostly adults here in Central and South AL. Now, in both South and North AL (including the TN Valley), we have another generation that was just mid aged immatures the second week of June. This means that we will likely have a migration from fleabane into cotton that will last for 3-4 weeks. Therefore, feeding and egg laying in cotton by these migrating adults will last 3-4 weeks. This will result in a long emergence of immatures in cotton beginning about first bloom.

We may need multiple applications pre bloom in some fields to control migrating adults. Then we may also need multiple applications post bloom for the immatures as they hatch. I hope I am over estimating what could be a bad plant bug year. This is not what we needed on 2 gene cotton. Multiple plant bug sprays just before the CEW flight comes from corn will result in more escape bollworms in mid-late July.

One thing we can do if this scenario happens is to use a plant bug application for adults about first bloom and add the IGR Diamond to the tank mix. Diamond will add residual control on hatching immature plant bugs for 10-20 days, depending on the rate used.

I will be focusing and making observations on plant bugs for about the next 3-4 weeks, and I will keep everyone updated on what we are seeing. The first report of high numbers of adult TPBs in cotton came from west central AL on June 19.

An Extension publication overviewing plant bugs was prepared by Barry Freeman, our resident plant bug expert in 1999 and can be found online at http://www.aces.edu/pubs/docs/A/ANR-0180/ANR-0180.pdf. Life cycles, damage, scouting, and management have not changed over the years. Every season and field are different, which requires close monitoring in order to make the proper management decisions.

2018 Treatment thresholds and control recommendations can be found in ACES publication # ANR-0415, “Cotton IPM Guide” available online at http://www.aces.edu/pubs/docs/I/IPM-0415/IPM-0415.pdf

If fieldmen, growers, or consultants have plant bug observations, please call or text and share with me at 334-332-9501. You may email me at smithrh@auburn.edu.

Insect and Crop Update for the Week of June 23

After going weeks with light to moderate thrips pressure, damage was heavy on 4-7 leaf cotton in early June, especially in SW Alabama.

Cotton was growing rapidly but thrips damage on true leaves was showing heavy damage from about the 4^th to 7^th true leaf. (Peanuts also were taking heavy damage during this same period.)

The thrips window is over now and we need to shift our focus to spider mites, aphids and the plant bug complex which includes tarnished plant bugs, fleahoppers and an occasional clouded plant bug.

Mites are primarily found in the TN Valley region of North Alabama and some treatments were being applied last week.

I noticed the first aphids on April planted cotton in central Alabama last Friday (June 21).

Plant bug numbers (adults) were down last week but nymphs are beginning to appear in our earliest planted cotton (mid-April). I would suggest using a sweep net to sample adults for the next 2-3 weeks, depending on the age of the cotton. As we approach first bloom I would switch to a drop cloth and concentrate on the presence of immature plant bugs.

Also, field men should now be looking at pinhead square set. Fields surveyed on June 21 were setting about 90% of the fruit. However, some plants had up to 30% square loss at that point. I believe you will find that migrating adult tarnished plant bugs will seek out the earliest planted and most lush cotton fields. My thought is that this cotton provides the best shade from the 95 degree temperatures, and is the best host for plant bugs.

While looking for pinhead square set I noticed a number of white eggs, likely tobacco budworms. They would not be a concern now, but in the old days it would have created a real predicament. Spraying for plant bugs during a budworm moth flight would have been expensive and also put the grower on a treatment treadmill for the remainder of the season. Sometimes we forget how well we have it compared to the pre-Bollgard years.

On another insect – a few stink bugs are already present in cotton. Normally we do not worry about stink bugs until about the third week of bloom, when we have bolls that are 10-12 days old. However, when stink bugs are present at bloom they will attack thumb sized bolls as soon as the bloom tag sheds. Any feeding to bolls this size will cause the boll to abort. Therefore, fieldmen need to be alert for adult stink bugs in early bloom cotton as they monitor for plant bugs with a sweepnet. Stink bugs will not damage squares or blooms but will seek out these first small bolls.

Since some of our corn was planted later than desired, stink bugs will likely remain with that host until the post roasting ear stage when the kernels become hard. At that time we may have a large movement into other crops such as cotton, soybeans and peanuts.

One word about Kudzu bugs on soybeans. Numbers of adults are out of site on many of our April planted beans. In fact, adult numbers are beginning to decrease in some fields now but numerous immatures are present, which is the trigger we use to treat the field. Fieldmen who have not experienced this insect may overlook these immatures when they are small. They will be a clear to greenish color and very small after hatching.

Insect Update on Cotton and Soybeans

As of 8:45 am Monday, June 10, all is quiet on the insect front. Rainfall during the past week has given cotton a growth spurt. Youngest cotton is 3 to 5 true leaves and overall has little thrips injury. Older cotton is at the 5 to 9 true leaf stage. Many fields are between the thrips injury stage and the stage where we begin to focus on plant bugs. This window is about 7 to 10 days long. Mid April planted cotton already has 2-3 pinhead or larger squares and should be scouted for adult plant bugs. No aphids or spider mites have been reported.

We will be conducting scouting schools in Autaugaville (central AL) and Headland (Wiregrass area of SE AL) this week. In addition to cotton and soybean insects (Kudzu bugs) we will also have presentations on cotton disease and resistant weed management.

Kudzu bug adults are attacking early planted soybeans in the Prattville, Tallassee and Auburn areas. At present our treatment threshold is 5 adults per plant.

Insect and Weather Update for the week of July 9th 2012

The past 10 days have been characterized by heat, drought, scattered thunderstorms, aphids, and in some cases spider mite decisions. Some areas have received one or more rainfall events of 1 to 3 inches or more while others are still suffering extreme drought. Some of these storms have brought high winds, downed trees, demolished buildings and hail.

Insects have been rather quiet overall. Many field men have made aphid treatment decisions with significant acres treated. In at least one incidence, both aphids and mites were at treatment levels. Other more sporadic fields have needed adult tarnished plant bug controls. In the majority of cases the plant bug population has now shifted to immatures. In these cases field men need to switch from sweep nets to drop cloths to quantify these immature plant bugs. Two or three immatures per drop could be considered a threshold level requiring treatments, especially if “dirty” blooms are present. Pinhead square retention is no longer the best way to look for plant bug damage since they spend more time down in the canopy feeding on larger squares (which later become dirty blooms).

I have not had any calls yet, but field men in the southern areas of the state need to pay attention to stink bugs since our oldest fields are now at week three, four or more of bloom. Weeks three through six of bloom is when stink bugs are most damaging. A good threshold for treatment during this period is 10-15% internal damage to quarter diameter (still soft) 10-12 day old bolls. Look for brown areas near the seed  and warts on the inside boll wall where stink bugs have penetrated in search of a protection source in the form of developing seed. If the population of stink bugs is primarily the southern green species then we have choices of both pyrethroid and phosphates. However, as most likely the case, the population may be predominately brown stink bugs. Here we would need a phosphate such as Bidrin or either a high rate of bifenthrin and get decent suppression.

Reports were just received of an increase of small larvae on peanuts in south-central Alabama. My guess would be that they are tobacco budworms. By July 15, newly hatched larvae will more likely be corn earworms.

Pest Update

The dominant factor in cotton the past one to three weeks has been the drought and heat. The weather has impacted both the crop directly and management decisions for insects. Some localized areas received rainfall on July 1 or 2. However, most cotton remains under stress from lack of moisture.

Aphids are the insect of primary concern since populations have built in many fields, putting additional stress on plants. Most growers delayed treatment decisions for aphids until this week – waiting for either rainfall or natural diseases. However, many are wisely spraying for aphids this week.

In some fields plant bugs are also present. Adults have diminished statewide but immatures have begun to emerge in many fields. I have also noted the presence of fleahoppers (both adults and nymphs) and clouded plant bugs in the mix. Field men have reported a large increase of bollworm moths in southwest Alabama fields this week.

Another significant even in row crop insects occurred during the past week. Kudzu bugs were observed feeding on soybeans in numerous fields in Cherokee County and in other fields in north Cleburne County and near Collinsville in Dekalb County. This pest has the potential to dramatically impact soybean production in Alabama as it already has in Georgia, South Carolina and North Carolina. First of all, soybeans will need to now be “scouted” as cotton has been since the late 1950’s. Mid-season (July) sprays will likely be required which will open the door for greater problems with podworms. Additional later sprays for the Kudzu bug will also be necessary. We will talk later about scouting techniques, thresholds and the selection on appropriate chemistry.

Weather Conditions and Pest Control

First we will give an overview of weather conditions, especially since this may be impacting some of our insect and pest control decisions in the coming days. After a good moisture and rainfall pattern of about 10-14 days ago, our crops have reached a hot-drought stressed condition at present. The situation is worse in the northern area of the state where less rainfall fell during the last thunderstorm period. I saw corn wilted bad in the Tennessee Valley on Tuesday (June 19).

This droughty situation could well impact spray decisions with pests such as aphids and s. mites in the immediate days ahead. Aphids are building state wide and drought stress plants are where I am more suggestive for chemical controls instead of waiting for the natural fungus.

Tarnished Plant Bug adults are also being reported from some fields from the Tennessee line in the north to the Florida line in the south. Square retention is dropping, especially in fields in South Alabama that are a couple of weeks into bloom – these would be early-mid April planted cotton. Also in these some fields, adult brown stink bugs are being reported. We know from past years what stink bugs do to small thumb sized bolls when no larger ones are present.

If present in cotton, stink bugs will feed on small bolls to develop. Knowing this impacts the chemical that we may want to choose for TPB control. It needs to be a product that also controls or highly suppresses Brown Stink Bugs. The best options here would be Bidrin or a high rate of bifenthrin. Aphids in the picture would further complicate the chemical selected. Of the neonic type products, Centric might be the best choice for Tarnished Plant Bug adults, Brown Stink Bugs and aphids.

Three-Cornered Alfalfa Hopper damage is still evident in cotton, in reddish stunted plants that have a girdled and swollen area around the main stem. However, this damage is old now and most plants are too tough for main stem girdling by the Three-Cornered Alfalfa Hopper.

The biggest insect news of the week in Alabama was the finding of the Kudzu bug in soybeans in Cherokee County, Alabama on June 21. The Kudzu bug had been found in about 25 counties on Kudzu but this was the first find on soybeans. Alabama growers will want to lean heavily on recent research conducted in Georgia, South Carolina, and North Carolina on this new envasive pest. We need to beef up our scouting on soybeans for this pest – especially the immature stage.

Announcing Alabama Scouting Schools

Announcement: Alabama Cotton Scouting Shortcourses Meeting Sites and Dates

• June 12^th (Tuesday) 2012; Autaugaville, Alabama- County Agricultural Center
• June 13^th (Wednesday) 2012; Headland, Alabama- Wiregrass Research Center
• June 19^th (Tuesday) 2012; Belle Mina, Alabama- Tennessee Valley Research Center

All meetings begin at 8:30 AM

Contact Person: Dr. Tim Reed (256-627-3450) or Dr. Ron Smith (334-332-9501)

Note: Dr. Austin Hagan will discuss cotton diseases at the Autaugaville and Headland sites. Dr. Tim Reed will cover soybean insects at all three sites.

Following are thirteen questions that represent the type of information that will be discussed.

1.      Why are grasshoppers easier to control in March/early April than May?

2.      If a foliar is needed for thrips suppression, when is the ideal stage of cotton to apply it?

3.      If you see damage to cotyledon stage cotton (no till) planted behind corn residue, what is the most likely culprit: snails, slugs, or pill bugs?

4.      What is the best method to determine when plant bug controls are needed in pre-bloom cotton?

5.      How would you measure the number of tarnished plant bugs in post bloom cotton?

6.      You are at week four or five of bloom, what would be the threshold for stink bugs?

7.      Under what conditions (situation) would a phosphate insecticide give better control of stink bugs than a pyrethroid?

8.      What new thrips insecticide entered the market this season and does not flare aphids or spider mites?

9.      Suppose you find high numbers of fall armyworms feeding on grass in your cotton field border- should you prepare to spray the cotton?

10.   How old does a green boll need to be to be safe from stink bug damage?

11.   Under what conditions would aphids be more of an economic pest or problem?

12.   At what stage is cotton normally beyond thrips injury?

13.   How long should you wait to evaluate control behind a stink bug spray?

Fine Tuning Cotton Insect Management for 2012

I. Thrips Control

1. Need for foliar overspray
• Influenced by planting date primarily but also to lesser degree by night temperature and overall growing conditions
• Seed treatments planted from early April to about May 10th would benefit from foliar overspray
• Seed treatments give 21 day thrips suppression as opposed to 28+ days with in-furrow granules
• What you see with thrips injury above ground is reflective also of underground root conditions and growth

2. Timing of overspray
• Most beneficial when most of plants have 1st true leaf about the size of a small finger nail
• Cotton with 4 or more true leaves usually does not benefit from overspray
3. Multi state research in 2011 indicated that acephate (Orthene or generics) was equal to or superior to all other choices
• Certain pyrethroids were a weak choice
• Bidrin is effective but I would suggest saving for stink bug control. New label limits total use of Bidrin in one season to 1.2 lbs active.
• New products tested: Benevia (Dupont) and Radiant ( Dow). Both looked very effective but not certain about registration date and cost.

II. Nematode Management

1. Rotation- peanuts, grain sorghum, corn
2. Variety selection- PHY367WRF has root knot tolerance
3. In-furrow granules
• Loss of Temik
• Meymik registered on December 22, 2011 (production and supply for 2012 uncertain)
4. Seed treatments
• Suggest to use on lower risk fields
• In high nematode risk fields would be like using a Band-Aid when a tourniquet is needed
5. Fumigate (Telone)
• Consider site specific nematicide placement (Precision Ag)
• Nematodes usually not evenly distributed across field
6. Deep tillage- grew cotton over 100 years without nematodes being a limiting factor- only since reduced tillage have they become a major problem

III. Plant Bugs

1. Movement from wild host into cotton influenced by climate
• Hot/dry results in high peak but short in time
• Wet/cool spring results in low movement over longer period
2. Most effective insecticides
• Acephate (Orthene, generics)- can flare spider mites
• Bidrin- good but only labeled for post bloom period
• Centric- effective but hard on beneficials and fire ants
• Pyrethroids- can flare spider mites
• Diamond- very effective on immature stage post bloom, especially when tank mixed with one of the above
• Intruder, Carbine, imidacloprid (Trimax), Belay, Vydate- less effective than others with one application

IV. Plant Bugs + Aphids (July)

1. Intruder, Carbine, imidacloprid (Trimax, etc.), Centric
2. Diamond may be combined with the above

V. Mid Season Worm Overspray

1. May be more important with Phytogen varieties
2. Timing could be mid July to early August depending on your north to south location
3. Pyrethroids are a good fit here
4. If brown stink bugs are also present, may want to select bifenthrin or Bidrin XPII (combination of Bidrin + Bifenthrin) or use highest labeled rate of other pyrethroids
5. Role of Fire Ants in Cotton
• Are the dominant beneficial in Alabama cotton today
• Not only important in conventional systems but also reduces escapes in Bollgard and WideStrike (Example: Mississippi consultants spray BGII on % egg lay)
• Some chemicals suppress fire ants more than others (Centric, Steward, pyrethroids, imidacloprid)
• Dr. Tim Reed and I conducted a project at Prattville last season (Poster Presentation)
• Results show less boll damage on both conventional and genetic cotton with fire ants in system as opposed to no fire ants
• Numbers on the side represent the number of worm damaged bolls per 45 feet.



Impact of Fire Ants On Bollworm
Damage in Alabama Cotton

VI. Fall Armyworms

1. 2010 and 2011 seasons have produced widespread outbreaks of the “grass” or “rice” strain of the FAW
2. This strain primarily attacks pastures, hay, grasses and peanuts and are easy to control with most insecticides, including pyrethroids
3. They do not prefer to feed on cotton or corn

VII. Stink Bugs

1. Some level of scouting needed for most economical control
• May need 0-4 sprays ($6-9 each considering application)
• Could pay for a field scout with savings or reduced damage from stink bugs alone
2. Most effective scouting is to examine 10-12 day old bolls for internal injury
3. Use “dynamic” or sliding threshold which considers the number of bolls at risk at a given week of bloom

4. Possible Reasons for Low Stink Bug Pressure in 2011
• Winter temperatures (colder than recent winters)
• Southern green stink bug is very sensitive to cold weather
• Impact of hot, dry spring on wild host/corn—may have reduced numbers of brown stink bug species
5.  New Stink Bugs
• Brown Marmorated Stink Bug
• Kudzu Bug (soybeans)
• Red-Banded Stink Bug (soybeans)  



Brown Marmorated Stink Bug



Red Banded Stink Bug

 

Kudzu Bug

 

VIII. New Products and Technology

1. Sulfoxaflor (Transform)- Dow
• Effective on plant bugs and aphids
2. Beseige (combination of Karate + Coragen)
• Effective on broad spectrum of caterpillars (loopers, fall armyworms), plus would have green stink bug activity
3. Endigo (combination of Karate + Centric)
• Effective on certain caterpillars, plant bugs, aphids and green stink bugs
4. Belay- in market place for past two seasons for plant bug/stink bug control
• Still need more University research to get a good handle on effectiveness
5. Prevathon (Dupont)
• One of most active caterpillar insecticides ever developed
• Excellent residual, depending on rate
• Very rainfast
• Should be targeted at egg stage or small larvae
6. Bayer Twin-Link
• Contains multiple Bt genes
• Performs somewhere between WideStrike and Bollgard II for caterpillar control
7. Bollgard III
• Under development
• Third gene is not a Bt so it has multiple modes of action for worms
• Reduces escapes over Bollgard II and will provide long term resistance management for the genetic technology
8. Poncho/Votivo Seed Treatment
• Insecticide + biological nematicide
• Looked at it in one trial on cotton and could see growth response and earliness, even under low nematode pressure



Overview of 2011 Cotton Insect Season

Early Season Pests
Thrips were extremely heavy from about April 15 to May 20. A major contributor to this heavy migration of thrips from wild hosts and wheat into cotton was the extreme drought conditions and absence of rainfall events during this period.

Plant Bugs
One peak movement of adult TPB into cotton occurred between June 20 and July 1. The majority of this infestation only happened in the earlier planted fields (most mature cotton). One insecticide application was targeted to these adult TPB’s when they were detected. Few immatures were detected in these fields in the coming weeks, so no in-field generation occurred. This may have been influenced by the extreme temperatures that occurred during this period (98-102⁰F).

Bollworm
Subeconomic numbers of bollworms occurred over an extended period from about July 15 to August 10. Few fields ever reached treatment threshold. 2011 was like the lowest bollworm pressure year on record. End-of-season damage boll counts on untreated genetic cotton were less than one boll per 10 feet.

Tobacco Budworm
Budworm numbers were non-detectable to extremely light all season long. Budworm larvae were too low to detect on conventional cotton and even on attractive crops such as tobacco when used as a sentinel crop.

Aphids
Aphid numbers were very slow to build in 2011 but also slow to crash due to naturally occurring diseases. The fungal disease was slow to develop which left aphids in the system much later than normal. Aphids normally peak and crash prior to, or at, the early boll set stage but this did not happen in 2011. Also, observations indicated a resurgence of aphids in the mid canopy area of the plants in late season as opposed to the terminal area.

Stink Bugs
Stink bugs in 2011 were fewest in number and damage of any year since the boll weevil was eradicated. This was likely due to the colder than normal winter temperature effect on the southern green species and the extreme spring heat and drought effect on the brown species. The majority of the few stink bugs observed in 2011 was the brown species.

Fall Armyworms
The “rice or grass” strain of the fall armyworm was abundant over much of the season in pastures, hay, and grasses. This strain will feed on peanuts but not on corn or cotton. They are easy to control on pastures with pyrethroids and numerous other labeled agricultural insecticides.

Aphids Reoccurring in Central Alabama Fields

Aphids have reoccurred in some central Alabama fields in the past week. Their infestation pattern on the plant is distinctly different from that of the aphids that normally occur in June and July. These August aphids are occurring down midways in the canopy while the terminals of the plants are aphid free.

Aphid numbers continue to build, while most insects numbers remain at moderate levels

Insect conditions have not changed greatly in the past week or so. Aphids have continued to build in more fields. All other insects are low to moderate levels (mostly sub-threshold). These include plant bugs (including a few clouded plant bugs coming into the mix), bollworms, tobacco budworms and stink bugs. Most growers do not have enough of a single species to apply controls for. The two biggest surprises at this point in the season are the low number of bollworms and the low number of stink bugs in most fields. Numerous fields of conventional cotton still have less than 2 bollworms per 100 plants. Boll damage to stink bugs is less than 10% in most fields.

Most of the state has had abundant thunderstorms for several consecutive weeks. Cotton yield prospects have improved greatly and, if conditions continue, numerous fields have two bale plus potential. The two biggest limitations we now have are fields with “skippy” stands and too much late maturing cotton.

Later than normal aphid buildup may require more proactive treatments

More fields were reported with aphid infestations last week. Due to this later than normal aphid buildup, growers may want to be more proactive in applying treatments. Stress from aphids, where they are occurring in 2011, is overlapping early to mid boll set. We need to set all the fruit possible in the next two weeks.


Both the brown and Southern stink green stink bug species are present at some level in many fields. Cotton planted in April and up to mid May is already into the third to sixth week of bloom. This means that we should be using a low (10%) internal damaged boll threshold for stink bugs. Growers who chose to treat for aphids should consider stink bugs when selecting their chemicals or tank mixtures.

The flight of corn earworms from corn to cotton usually occurs the week of July 20 in central Alabama. This egg lay may occur up to 7 days earlier in south Alabama and 7 days later in the northern counties. This budworm flight will only be meaningful to those who have planted conventional cotton varieties. Older larvae observed last week were likely from budworm moths that occurred 1 to 2 weeks ago.

Tarnished plant bug, aphid, tobacco budworm and fall armyworm numbers on the increase

Tarnished plant bug adults were found in numerous fields in western Alabama (Lamar County) on Friday (July 8). Pin head square loss was minimal (less than 5%) and very few immature plant bugs were found. This would indicate that adults had moved into cotton fairly recently. However, this is a situation where damage could increase rapidly if controls are not applied.

Several calls were received late last week about increasing aphid populations in some fields. Aphids are late developing this season, which means they also could be late crashing from the fungal disease. This being the case, the peak aphid stress will come during the early boll set window. Growers may find it best to apply aphid controls and prevent plant stress at this stage of maturity.

Heavy tobacco budworm damage has been occurring on sentinel plots of conventional cotton in SW Georgia for the past week. Growers with Bollgard II and Widestrike can sleep well at night knowing that their investment in technology is working to near perfection.

The “grass” strain of the fall armyworm is now damaging pastures and hay crops in several south Alabama counties. This strain will also feed on peanut foliage but will not feed on cotton.

Stink bugs, tarnished plant bugs and "worms" in cotton

My cotton insect observations this week were as follows: many fields have a number of immature (late instar, soon to be adult) tarnished plant bugs. This stage of immature, along with the adult stage, is what will be giving us our “dirty” blooms in the days ahead. Mixed in with these immature TPBs are a few fleahoppers (both immature and adults) and a few immature clouded plant bugs. Many fields would profit from a plant bug complex “clean-up” spray if it has not already been done during the past two weeks.

Aphids have built rapidly during the past week in a number of fields. Where cotton is currently under drought stress, the presence of aphids and honeydew on all plants might influence the choice of chemistry for this bug clean-up spray.

Several fields of April planted cotton in southeast Alabama had treatable levels of “worms” this week. These worms were likely already about a week old on July 15, which means the eggs were deposited around July 5. This was during the period when most moths observed were tobacco budworms. Appropriate chemistry would be needed if targeting these worms. By next week (July 19-26) the eggs deposited will likely be bollworms and pyrethroids would be the most economical chemistry.

Even though the percent internal boll damage may not have increased in recent days, the brown stink bug problem has not gone away. My thought as to why the percent damage hasn’t gone up is due the fact that peak boll production is close in cotton planted in late April. Let me explain. A week or two ago we had about one boll per row foot about 10-12 days old (the size stink bugs prefer). Some of our stink bug damage levels at that time were running 20% or more. At one per foot this would be about 14000 bolls per acre x 20% or 2800 per acre with internal damage. At present these same fields have up to 3 or more 10-12 day old bolls per row foot. This would mean that 42000 bolls per acre are at risk, but the stink bug population hasn’t increased greatly at this point. The percent internal stink bug damaged bolls has gone down in many fields but that doesn’t mean we are not taking economic damage. Ten percent damage to 42000 bolls per acre is 4200 bolls. Percentages can be misleading. The damage we are incurring is a function of two things – the number of bugs present and the number of bolls at risk. In the old days this situation existed with the number of squares and the number of boll weevils. The damage percent would go down prior to increasing rapidly.

Not only will we wake up one day a couple of weeks down the road with more internal stink bug damage than we thought, but also with a sharp increase in the percent damage. This will be a function of more stink bugs present by then, but also a reduction in the number of bolls per acre that are in the desired feeding size. Borrowing a line from one of our recent politicians “this makes sense to me – does it to you”?

Aphids and bug complex building, fall armyworms in second generation in pastures, fleahoppers appear

We’re getting more reports of aphids building in cotton. They’ve been slow to increase but still have reached treatable levels in some fields. While we were doing our beat sheets last week, I noticed in some of the older cotton that immature brown stink bugs were turning up where we had adult brown stink bugs earlier. So, they’ve been in there long enough now to turn over a generation. Most of the plant bug population right now are in immature forms coming off of the June adults. Fields that were sprayed for bugs appear to be pretty clean, but others have populations now that are at or will shortly be at damaging levels, so we’re really close to making applications to clean up the bug complex on everything.

We’re still not seeing signs of the huge tobacco budworm flight that was underway in southwest Georgia 2 weeks ago. It’s amazing how fast budworm activity drops off as you travel 2 counties west into Alabama. We have a long history of similar patterns – heavy pressure in south Georgia but hardly anything in southeast Alabama. We’re into the second generation of fall armyworms, the grass strain, in coastal Bermuda and other hay fields in southeast Alabama.

The garden fleahopper has been causing damage in a 25-acre cotton field in Mobile County. This is the first time I’ve seen the pest in cotton in the 39 years I’ve been working the crop and didn’t know for sure what the insect was when a consultant emailed me samples of the pest and damage. But Mississippi State University recently released an excellent color insect guide for cotton, and the garden fleahopper was included in it, which allowed me to ID the insect. Evidently, it’s been enough of a pest at some point in Mississippi cotton that it made the book.

I have a feeling we’ll see a lot of brown stink bugs in soybeans when they start setting pods. They’re certainly nearby, although probably not in soybeans to any degree yet. Stink bugs are smart enough that they won’t hang around too long in a crop that doesn’t provide a food source. Typically, they’ll leave corn within a week of when it starts drying down and, as if on cue, they’ll shift into soybeans when they start setting pods. We’re following a population of them right now at our Gulf Coast research station.

Insect Complex Developing

Several fields were surveyed yesterday (7/6/2010) in central Alabama. My findings were as follows: aphids continue to be low to non-detectable in many fields; drop cloth samples yielded early instar immature plant bugs, and an occasional fleahopper, frequent adult clouded plant bugs, and adult brown stink bugs. All of these were at non-treatable levels at the present. However, as each day and each week passes the bug complex will become more abundant and damaging to the point that the entire complex will require controls. I would key on damage to the thumb sized bolls (until quarter diameter bolls are present) for stink bug decision and to a combination of dirty blooms and the number of immature plant bugs per row foot for that species.

I would advise field surveyors to begin switching from a sweep net to the drop cloth as cotton begins to bloom. The majority of the plant bug population for the next couple of weeks will be immatures that have hatched from eggs deposited by migrating adults during the month of June.

The large tobacco budworm flight has not reached southeast Alabama yet. I will be in southeastern Alabama tomorrow and will observe for moths, eggs, and small larvae at that time.

Calls received this week have centered on what to use for a complex of aphids, plant bugs and brown stink bugs. No one chemical would be the top choice for this complex. A pre-mix or a tank mix of two chemical classes would likely give the most effective control of this complex.