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Friday, July 20, 2018

Howdy,

  All the cotton I've looked at this week is past cutout (5 nodes above white flower) and a good number of fields have open bolls. I've been seeing the bollworm (H. zea, corn ear worm, etc.) egg lay decreasing, and most of the larvae are cycling out. Last week I spent a good deal of time collecting bollworms out of double traited and one vip traited field. Those bollworms have been sent to the lab in College Station for Bt resistance testing.

Large Cotton Bollworm in Cry 1Ab + Cry 2Ac Cotton
Photo: Kate Harrell

Treatment options for Cotton Bollworm in Cotton

  In places still susceptible to bollworms, it's important to be checking for them even if you have Bt cotton. There is no threshold set for egg lay (since they have to feed for Bt to effect them and many other insects consume eggs), but our adapted threshold for caterpillars after last year is 6% damaged bolls or squares with live caterpillars present. When cotton reaches cutout (5 NAWF), it has 350 heat units remaining before the bollworms can no longer cause yield loss.

Stink Bug
Photo: Kate Harrell
Carpal Warts in Cotton
Photo: Kate Harrell
  In the places that are still susceptible to stink bugs, the threshold for stink bugs is 20% of bolls damaged with stink bugs present. Once cotton has reached 450 heat units past cutout, treatment for stink bugs may no longer be necessary, as the bolls they can still feed on will not mature in time to contribute to the overall yield. Fields that experienced drought stress this year may have a longer time frame for yield loss to occur, and stink bugs may still need to be a consideration until 450 heat units past 3 or 4 NAWF.

Hope everyone has a great weekend and safe grain harvest!

Sincerely,

Kate

For more information check out:

Texas Row Crop Newsletter

Managing Cotton Insects in Texas

Friday, July 13, 2018


 Wharton - AgriLife Extension to host a Cotton Turn Row Meeting – July 17th

 By Corrie Bowen
County Extension Agent
Wharton County

Texas A&M AgriLife Extension, Wharton and Matagorda County Offices will host a Cotton Turn Row Meeting on Tuesday, July 17, 2018 in Wharton.  Registration will begin at the Directors Room at the Wharton County Fairgrounds at 8:30 a.m.  Program to begin at 9:00 a.m. with an overview of the 2018  Cotton Crop.  We’ll then proceed to our Replicated Agronomic Cotton Evaluation (RACE) trial where we’ll hear from Dr. Gaylon Morgan, Extension Cotton Specialist with discussion on cotton varieties and late season issues.  Dr. Scott Nolte, Extension Weed Specialist will follow with discussion on minimizing off-target herbicide movement.  By 11 a.m. we’ll return to the Directors Room where Greg Baker with discuss Worker Protection Standard requirements for pesticide workers and handlers. 

The WPS is a federal regulation originally enacted in 1992 designed to protect agricultural workers (people involved in the production of agricultural plants) and pesticide handlers (people mixing, loading, or applying pesticides or doing other tasks involving direct contact with pesticides). You probably need to comply with the WPS if you are a:  Manager or owner of a farm, forest, nursery, or greenhouse; or Labor contractor for a farm, forest, nursery, or greenhouse; or  Custom (for hire) pesticide applicator or independent crop consultant hired by a farm, forest, nursery, or greenhouse operator.  The EPA made significant revisions to the WPS provisions that became effective January 2, 2018.  Most WPS provisions are protections that you, as an employer, must provide for your own employees and, in some instances, to yourself. The WPS covers two types of employers, which it defines according to the type of work their employees do.  Bring your farm employees (agricultural workers and/or pesticide handlers) to the July 17th Turn-Row meeting, as the WPS training at 11 a.m. will satisfy the annual WPS training.  The WPS training video will be provided in English.  Please contact the Wharton County Extension office prior to July 17th at 979-532-3310 if you have employees attending who will need to view the Spanish version of the WPS training.

Program will conclude at noon.  3 CEUs will be offered for TDA pesticide license holders and 3 CCA credits have been applied for.  Please call the Extension Office by  5:00 p.m. on July 16 just to let us know that you’ll be attending.  A flyer  for the July 17th turn-row meeting is available at https://wharton.agrilife.org.


The members of Texas A&M AgriLife will provide equal opportunities in programs and activities, education, and employment to all persons regardless of race, color, sex, religion, national origin, age, disability, genetic information, veteran status, sexual orientation or gender identity and will strive to achieve full and equal employment opportunity throughout Texas A&M AgriLife. The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating.  Individuals with disabilities who require an auxiliary aid, service or accommodation in order to participate in any Extension activity, are encouraged to contact the County Extension Office for assistance 5 days prior to the activity.

Friday, July 6, 2018

Check your Bt for Bollworms

Howdy everyone,

Bollworm Egg
Photo: Kate Harrell
  I've looked at cotton past cutout (5 nodes above white flower) in all three of my counties this week, this season has been flying by. I've been seeing the bollworm (H. zea, corn ear worm, etc.) egg lay and some larvae. The most larvae we found this week was near Elm Grove, with 5 small caterpillars on 100 plants. I spent a good bit of time in a field trial location this week, and was finding a few live caterpillars in everything but the Viptera traited cotton.

  Most of our Bt technology is not working as well as it has been in the past, as we saw last year. It still has some activity on worms, but when we tested last year in our area, the bollworms have resistance to all but the new Viptera trait. The chart below shows the current and past technologies, and the overlap between them. This overlap has helped select for bollworms that are no longer effectively controlled by the technology.


  Even if you have Bt cotton, it's important to be checking for bollworms. There is no threshold set for egg lay (since they have to feed for Bt to effect them and many other insects consume eggs), but our adapted threshold for caterpillars after last year is 6% damaged bolls or squares with live caterpillars present. When cotton reaches cutout (5 NAWF), it has 350 heat units remaining before the bollworms can no longer cause yield loss.

Large Cotton Bollworm in Cry 1Ab + Cry 2Ac Cotton
Photo: Kate Harrell

Treatment options for Cotton Bollworm in Cotton
Managing Cotton Insects - Page 31

  I am using the whole plant inspection method when scouting, and have been looking at 50 to 100 plants in 4 or 5 different places in the field, depending on the field size. I look over the entire plant and count the number of undamaged bolls or squares, and the number of damaged ones. I am also pulling 10-15 bolls at each spot I check to look for stink bug damage. Damage can entail carpal warts on the inside of the bolls, or brown and damaged lint and seed in the boll. The threshold for stink bugs is 20% of bolls damaged with stink bugs present. Once cotton has reached 450 heat units past cutout, treatment for stink bugs may no longer be necessary, as the bolls they can still feed on will not mature in time to contribute to the overall yield. Fields that experienced drought stress this year may have a longer time frame for yield loss to occur, and stink bugs may still need to be a consideration until 450 heatu units past 3 or 4 NAWF.

Carpal warts from stink bug feeding
Photo: Kate Harrell
  I'm still seeing some aphids in cotton as well. Treatment for aphids in cotton is rarely warranted at this growth stage. The threshold is at 40-70 aphids per leaf until bolls begin to crack. Once we have open bolls, the threshold drops to 10 per leaf, as the honeydew can cause mold to grow on lint and cause problems with harvest. If you know you have aphids and need to spray for either bollworms or stink bugs, try to either choose a more selective chemical for treating your pest to avoid knocking back the beneficial populations and flaring the aphids, or look for an insecticide with aphid activity as well.

Minute Pirate Bug eating an Aphid
Photo: Kate Harrell
 I hope everyone has a safe grain harvest!

Sincerely,

Kate Harrell

For more information check out:

Texas Row Crop Newsletter

Managing Cotton Insects in Texas

Sugarcane Aphid Scouting Card




Friday, June 29, 2018

Bollworms and Stink Bugs

Howdy everyone,

H. zea eggs on a cotton leaf
Photo: Kate Harrell
  This week I've been seeing the bollworm (H. zea, corn ear worm, etc.) egg lay picking up. The most this week was in a field near Egypt, 24% of the plants had eggs. When eggs are laid in multiples like in the photo above, only count it as one egg. Bollworms are highly cannibalistic, and only one caterpillar is going to survive being that close together. I've seen a few small worms, and a few 3 to 4 day old larvae. Most of our Bt technology is not working as well as it has been in the past, as we saw last year. It still has some activity on worms, but when we tested last year in our area, the bollworms have resistance to all but the new Viptera trait. The chart below shows the current and past technologies, and the overlap between them. This overlap has helped select for bollworms that are no longer effectively controlled by the technology.


  Even if you have traited cotton, it's important to be checking for bollworms. There is no threshold set for egg lay (since they have to feed for Bt to effect them and many other insects consume eggs) , but our adapted threshold for caterpillars after last year is 6% damaged bolls or squares with live caterpillars present.

H. zea larva in a cotton square
Photo: Kate Harrell
Treatment options for Cotton Bollworm in Cotton
Managing Cotton Insects - Page 31

  I am using the whole plant inspection method when scouting, and have been looking at 50 to 100 plants in 4 or 5 different places in the field, depending on the field size. I look over the entire plant and count the number of  undamaged bolls or squares, and the number of damaged ones. I am also pulling 10-15 bolls at each spot I check to look for stink bug damage. Damage can entail carpal warts on the inside of the bolls, or brown and damaged lint and seed in the boll. The threshold for stink bugs is 20% of bolls damaged with stink bugs present. I have been seeing some stink bugs, and a few of the consultants I've talked to have picked them up at above threshold levels.

Carpal warts from stink bug feeding
Photo: Kate Harrell
  I've been picking up aphids in cotton as well, the heaviest population I picked up this week was near Tidehaven school in Matagorda county. Treatment for aphids in cotton is rarely warranted at this growth stage. The threshold is at 40-70 aphids per leaf until bolls begin to crack. Once we have open bolls, the threshold drops to 10 per leaf, as the honeydew can cause mold to grow on lint and cause problems with harvest. If you know you have aphids and need to spray for either bollworms or stink bugs, try to either choose a more selective chemical for treating your pest to avoid knocking back the beneficial populations and flaring the aphids, or look for an insecticide with aphid activity as well.

  A few folks have contacted me about problems with sugarcane aphids in sorghum. At the bottom of the article I've included a link to the scouting card for them. Make sure to keep an eye on the pre-harvest interval for insecticide applications on those.

  Don't get too hot out there and have a good weekend.

Sincerely,

Kate Harrell

For more information check out:

Texas Row Crop Newsletter

Managing Cotton Insects in Texas

Sugarcane Aphid Scouting Card


Friday, June 15, 2018

Bollworms and Stink Bugs

Howdy,

  Several stink bug species feed on bolls in Texas cotton fields, and I've seen scattered stink bugs in all of my counties. Our primary stink bug species are the southern green stink bug, followed by the green stink bug, and brown stink bug. They are strong flyers and can move into cotton from corn, grain sorghum, soybeans, and various alternate hosts. Stink bugs have piercing-sucking mouthparts and damage cotton by piercing the bolls and feeding on the developing seeds. Stink bug infestations can cause substantial economic losses through reduced yield, loss of fiber quality, and increased control costs. Stink bugs favor medium-sized bolls, but they can feed on any size boll. Stink bugs may feed on bolls 25 or more days old, but bolls of this maturity are relatively safe from yield loss. Their feeding on young bolls (less than 10 days old) usually causes the bolls to shed. In larger bolls, stink bug feeding often results in dark spots about 1/16 inch in diameter on the outside of bolls. These dark spots may not always correlate well with the internal damage—callus growths (or warts) and stained lint. There may be several spots on the outside of a boll without internal feeding damage being present. Damage to the internal boll wall is a good indication that lint and seed are affected. Excessive stink bug feeding causes reduced yield, stained lint, poor color grades, and reduced fiber quality. In addition to direct damage, stink bug feeding can transmit plant pathogens that cause boll rot.



Green Stink Bug
Photo: Kate Harrell 
 Stink bugs are difficult to scout, especially in tall, vigorous cotton. Adults tend to group together, and the distribution of stink bugs within a field may be highly concentrated, particularly along field margins. Use any of the sampling techniques such as visual inspection, drop cloth, and sweep net for scouting. Recent research by entomologists at the University of Georgia and Clemson University suggests that decisions to treat for stink bug infestations are best made based on the percentage of bolls with evidence of internal damage (warts or stained lint associated with feeding punctures). To use this technique, remove about 10 to 20 bolls, one inch in diameter (about the size of a quarter), from each of four parts of the field, avoiding field edges, and break open the bolls by hand or cut them with a knife. Look for internal warts on the boll walls and stained lint on the cotton locks. 




Check bolls with visible external lesions first to determine if the internal damage threshold has been met, since bolls with external lesions are more likely to also be damaged internally. The action threshold is 20 percent or more damaged quarter sized bolls with stinkbugs present.


H. zea Moth
Photo: Kate Harrell
  I want everyone to be on the lookout for bollworms once your cotton starts to bloom. My field scout found 2nd instar larvae this week, and I have seen moths moving around more in cotton. The egg lay has begun picking up in all three counties this week as well. Last week the bollworm eggs were fewer and farther between, but this week they are picking up, especially in Jackson county. The egg lay near La Salle was at 17 eggs per 100 plants.


H. zea Eggs
Photo: Kate Harrell
  To scout for bollworms in Bt cotton, search the entire plant for larvae and injury. A proper sample includes squares, white blooms, pink blooms, bloom tags, and bolls. Reduce the scouting intervals to 3 to 4 days during periods of increasing bollworm egg-laying, especially during peak bloom. The presence of eggs alone should not trigger treatment since hatching larvae must first feed on the cotton plant to receive a toxic dose.

  To use the terminal and square inspection method, divide the cotton field into four or more manageable sections, depending on the size of the field. Examine 25 plant terminals (on the upper 1/3) of the plant), selected at random from each quadrant, for small larvae and eggs. Examine 25 half-grown and larger green squares, small, medium, and large bolls for bollworms and their damage as well. Keep track of the number of undamaged and damaged squares and bolls, and select fruit at random, not deliberately choosing flared or yellow squares in the sample. Pay attention to bloom tags and petals stuck to small bolls, as they can hide larvae burrowed into the tip of the boll.


  For the whole plant inspection method, once again divide the cotton field into four or more manageable sections, dependent on field size. Make whole plant inspections of five randomly chosen groups of three adjacent cotton plants in each section. Look in every square, bloom, and boll. Thoroughly inspect dried blooms and bloom tags attached to small bolls. Count the number of undamaged and damaged fruit and calculate the percentage of damaged fruit.

Managing Cotton Insects in Texas, pg 14
  Thresholds in Bt cotton fields are based on how many worms survive to late first or second instar larval stage, not on the newly hatched larvae or on the presence of eggs. Since newly hatched larvae must feed on the plant for the Bt toxin to be effective, base treatment decisions are made on damaged fruit and the presence of larvae. Insecticides in the diamide, oxadiazine, and spinosyn classes are more selective than the pyrethroid and carbamate classes. See the tables below for suggested insecticide options.

Managing Cotton Insects in Texas, pg 31
  A few weeks ago my intern and I placed large metal moth traps in each county, and loaded them with bollworm pheromone lure. I have included the past two weeks moth numbers below.

Week of June 4th

Wharton County:
5- Elm Grove
4- Near the Wharton Airport
0- Blue Creek Area

Jackson County:
21- El Toro
2- La Salle
0- Between Weedhaven and Palacios

Matagorda County:
0- Near Blessing
0- Near Tidehaven School
2- Tin Top

Week of June 11th

Wharton County:
7- Elm Grove
0- Near the Wharton Airport
0- Blue Creek Area

Jackson County:
81- El Toro
15- La Salle
6- Between Weedhaven and Palacios

Matagorda County:
11- Near Blessing
40- Near Tidehaven School
32- Tin Top

  Please feel free to give me a call if you have any comments or questions, or if you find bollworms in viptera traited cotton. Have a good weekend, and I hope we catch some rain!

Sincerely,

Kate Harrell




Friday, June 1, 2018

Pest Update, Off-Target Movement, and Africanized Bees


  Howdy,


  This week a good amount of our cotton is looking dry, especially in the areas that missed the rains last week. I've been keeping an eye out for stink bugs and for bollworms in the cotton that has started blooming, but I haven't seen or heard from anyone that's found more than a few moth eggs or a couple of stink bugs. I suspect most of the cotton will be blooming next week. In cotton that isn't as far along and still in peak squaring, fleahoppers are still a concern. The threshold for fleahoppers is 15 to 25 per 100 plants.
  I have gotten a few questions on off-target herbicide movement recently, and Dr. Morgan did a good job of addressing what is going on with his most recent Texas Row Crops Newsletter. Please feel free to check out that information here.
Green Stink Bug
Photo: Kate Harrell
  As our cotton continues maturing and we start to see bolls, its good to know that several stink bug species feed on bolls in Texas cotton fields. Our primary stink bug species are the southern green stink bug, followed by the green stink bug, and brown stink bug. They are strong flyers and can move into cotton from corn, grain sorghum, soybeans, and various alternate hosts. Stink bugs have piercing-sucking mouthparts and damage cotton by piercing the bolls and feeding on the developing seeds. Stink bug infestations can cause substantial economic losses through reduced yield, loss of fiber quality, and increased control costs. Stink bugs favor medium-sized bolls, but they can feed on any size boll. Stink bugs may feed on bolls 25 or more days old, but bolls of this maturity are relatively safe from yield loss. Their feeding on young bolls (less than 10 days old) usually causes the bolls to shed. In larger bolls, stink bug feeding often results in dark spots about 1/16 inch in diameter on the outside of bolls. These dark spots may not always correlate well with the internal damage—callus growths (or warts) and stained lint. There may be several spots on the outside of a boll without internal feeding damage being present. Damage to the internal boll wall is a good indication that lint and seed are affected. Excessive stink bug feeding causes reduced yield, stained lint, poor color grades, and reduced fiber quality. In addition to direct damage, stink bug feeding can transmit plant pathogens that cause boll rot.
  Stink bugs are difficult to scout, especially in tall, vigorous cotton. Adults tend to group together, and the distribution of stink bugs within a field may be highly concentrated, particularly along field margins. Use any of the sampling techniques such as visual inspection, drop cloth, and sweep net for scouting. Recent research by entomologists at the University of Georgia and Clemson University suggests that decisions to treat for stink bug infestations are best made based on the percentage of bolls with evidence of internal damage (warts or stained lint associated with feeding punctures). To use this technique, remove about 10 to 20 bolls, one inch in diameter (about the size of a quarter), from each of four parts of the field, avoiding field edges, and break open the bolls by hand or cut them with a knife. Look for internal warts on the boll walls and stained lint on the cotton locks. 
Check bolls with visible external lesions first to determine if the internal damage threshold has been met, since bolls with external lesions are more likely to also be damaged internally. The action threshold is 20 percent or more damaged quarter sized bolls with stinkbugs present.

H. zea Moth
Photo: Kate Harrell
  I also want folks to be on the lookout for bollworms as cotton begins to bloom. I have not found any larvae yet, but I have seen moths moving around in cotton. To scout for bollworms in Bt cotton, search the entire plant for larvae and injury. A proper sample includes squares, white blooms, pink blooms, bloom tags, and bolls. Reduce the scouting intervals to 3 to 4 days during periods of increasing bollworm egg-laying, especially during peak bloom. The presence of eggs alone should not trigger treatment since hatching larvae must first feed on the cotton plant to receive a toxic dose.
H. zea eggs
Photo: Kate Harrell
  To use the terminal and square inspection method, divide the cotton field into four or more manageable sections, depending on the field size. Examine 25 plant terminals (upper third of the plant), selected at random from each quadrant, for small larvae and eggs. Also, from each quadrant, examine 25 half-grown and larger green squares as well as small, medium, and large bolls for bollworms and bollworm damage. Keep track of the number of undamaged and damaged squares and bolls. Select fruit at random and do not include flared or yellow squares in the sample. Pay attention to bloom tags and petals stuck to small bolls; they will often hide larvae that burrow into the tip of the boll. 
  To use the whole plant inspection method, once again divide the cotton field into four or more manageable sections, depending on the field size. Make whole-plant inspections of five randomly chosen groups of three adjacent cotton plants in each section. Look in every square, bloom, and boll. Thoroughly inspect dried blooms or bloom tags attached to small bolls. Count the number of undamaged and damaged fruit and calculate the percentage of damaged fruit.
Managing Cotton Insects in Texas, pg 14
  Thresholds in Bt cotton fields are based on how many worms survive to late first- or second-instar larval stage, not on newly hatched larvae or the presence of eggs. Since newly hatched larvae must feed on the plant for the Bt toxin to be effective, base treatment decisions on damaged fruit and the presence of larvae. Insecticides in the diamide, oxadiazine, and spinosyn classes are more selective than the pyrethroid and carbamate classes. See the tables below for suggested insecticide options.

Managing Cotton Insects in Texas, pg 31
  Two weeks ago we put out 3 large moth traps in each county with Helicoverpa zea (bollworm) lure in each. Below I have included the number of bollworm moths caught this week at each location.

Wharton County:
3- Elm Grove
0- Near the Wharton Airport
0- Blue Creek Area

Jackson County:
31- El Toro
3- La Salle
2- Between Weedhaven and Palacios

Matagorda County:
0- Near Blessing
0- Near Tidehaven School
1- Tin Top

  These moths are probably moving out of corn and sorghum and will be moving into cotton as our growing season progresses.
  This week I had a couple questions on africanized honey bees, and my intern, Jared Schindler looked up some information to share on them. Check it out below:


Africanized Honey Bees

  Africanized Honey Bees, also commonly known as Killer Bees, began their trek to the United States when hive queens escaped from a researcher in Brazil, causing the rest of the hive to follow suit. From there, they naturally migrated northward and were first spotted in South Texas in 1990. With the naked eye, these Africanized Bees look the same as the native European Honey Bee. They are the same in nearly every way, including the venom, with the only differences being that the Africanized Bee is only microscopically smaller than the average honey bee, and Africanized Bees are much more irritable and susceptible to launching attacks on people, pets and wildlife.
  Other differing behavioral traits of the Killer Bee include the fact that these bees will begin a hive in places where native bees normally wouldn’t, such as closer to the ground, inside water meters, other manmade structures and abandoned bee hives. Africanized Honey Bees also swarm to a new hive more often, and overall, they are more aggressive and will defend the hive even if there is no direct threat or contact to the hive itself. There are many variables that can cause aggressive reactions from this particular species. Some include vibrations of heavy and light duty lawn care equipment, frantic animals, loud noises, and even someone or something being too close to the hive.
  In order to prevent one of these aggressive attacks happening to you or your pet, it is suggested that you bee-proof your home by sealing all cracks and holes on the exterior, clean up debris, unused equipment or any potential nesting crevice, place a screen over all major openings to your home and scout the property before doing any yard work that could disturb a hive.
  If you happen to find yourself in a situation where you’ve upset an Africanized hive, be sure to alert anyone in the immediate area, cover your face without blocking your vision and make an attempt to get to a safe, concealed space without looking for the colony. If you are stung, remain calm and remove the stingers by scraping them with either a knife or fingernail. If you’re allergic to bee stings, always carry an Epi-Pen if you believe you may be in an area where a sting can happen and if the attack is serious enough, remain calm and call 911. 
  Source: https://txbeeinspection.tamu.edu/public/africanized-bees/

Have a good weekend, everyone!

Sincerely,

Kate Harrell