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Friday, May 29, 2020

Flowering Cotton

Photo: Kate Crumley
Cotton Bloom
Photo: Kate Crumley

Howdy,

  This week Stephen Biles and I put together an audio update on what we are seeing going on in our areas. If you are interested in checking that out, you can sign up to receive text updates when we post them on Thursday afternoons at this website https://www.texasinsects.org/signup-coast.html.

  It was pretty muddy in all three counties this week. Our insect pressure definitely dropped off this week, and I am glad to see a lot of flowers out there. Cotton is out of danger of economic yield reduction from fleahoppers once it starts blooming. This week I only saw one field still susceptible to fleahopper damage with any fleahoppers present. I found 16% in a field in Matagorda county near Tidehaven.

  I am still seeing a few different plant bug species around, though in lower numbers this week. I haven't seen a verde yet, but I've talked to consultants that have. The threshold for verde plant bugs is 20-25 insects per 100 plants with using a beat bucket. Verdes can feed on fruit up to bolls about an inch in diameter.

Nymph (A) and adult (B) of Verde plant bug, Creontiades signatus Distant (Hemiptera: Miridae), which causes lint and seed staining and deterioration, seen in green (C) and open (D) cotton bolls. https://ccag.tamu.edu/entomology/

  If you've still got fleahoppers, they are an insect that feeds on plant materials, and will feed on cotton squares. Keep a sharp eye out for this insect, the adults are very flighty and are often easily scattered when walking fields. I try not to let my shadow hit a plant before I get close enough to look at it so I can see the adults before they fly. Below I have two photos, one of the nymph and one of the adult insect. The nymphs of these insects are also quite small, about the size of an aphid. They are also a pale green color, but lack wings. They lack cornicles (tailpipes) that an aphid would have, and tend to be more mobile than an aphid. Fleahopper nymphs also lack the bands on the antennae a few other species of plant bugs have, and have a similar body shape to the adult bug.

Cotton Fleahopper Nymph
Kate Crumley

Cotton Fleahopper Adult
Kate Harrell

  Fleahopper feeding will cause squares to drop. Plants can recover for and compensate for some square loss, but the threshold for fleahoppers is 15-25 per 100 plants. I check for fleahoppers by inspecting the plant terminals once they start squaring. I look at 25 plants per stop in the field, usually checking 100 plants total in an 80-100 acre field, more if the field is larger.


  The chart above with action thresholds if from the cotton insect guide, and the one below containing insecticide suggestions is from cottonbugs.tamu.edu.



  Lygus bugs will feed on cotton squares, flowers, and small bolls. Feeding can cause damage to blooms (dirty blooms and damaged anthers, or puckered petals), deformed bolls, stunted growth, fruit shed, and small lesions on bolls.

Lygus Bug nymph
Kate Crumley

Lygus Bug adult
Kate Crumley

Chart from Cotton Insect Guide


  I have only seen one stink bug in cotton so far this year, but now that our cotton is putting bolls on we need to look for them. To scout for stink bugs pull 10 to 20 bolls about an inch in diameter from four places in the field. Check the inside of the bolls for warts, lesions, and stained lint. The economic threshold for stink bugs is 20% or more of the bolls with internal damage and stink bugs present. Some of the brown stink bug populations in our area have also been shown to have some resistance to pyrethroids. 

Green Stink Bug adult
Kate Crumley

Carpal Wall Warts from Stink Bug feeding damage
Kate Crumley

  I have not seen any bollworms, Helicoverpa zea, or eggs in fields yet this year, but I have started looking for them. These are caterpillars that feed on multiple crops and vegetables. In cotton they feed on squares and bolls, causing fruit loss. The last few years we had high numbers of this insect in our Bt cotton as well.

H. zea caterpillar in cotton square
Kate Crumley

  To scout for cotton bollworms I use the terminal and square inspection method. I make about four stops in a field, more if the field is larger than 100 acres. At each stop, I look at 25 plant terminals, checking the upper third of the plant for caterpillars and eggs. I also pull 25 half grown or larger green squares to bolls and look for bollworm damage. This week there were a few moths flying around in a couple of the fields in Matagorda county, and in one near Palacios we found two eggs laid. When documenting egg lay, if I find more than one on a leaf, I only count it as one. This caterpillar is highly cannibalistic, and generally only one caterpillar will result from eggs too near each other. The economic threshold for bollworms is 6% damaged bolls with live caterpillars present. In areas like ours on the upper gulf coast with documented Bt failures, the threshold for eggs on single and dual gene cotton is 20% (20 plants out of 100 with at least one egg). If you're finding bollworms in cotton or in corn, especially in viptera fields, please give me a call.

Cotton Insect Guide
 The current A&M recommendation is to use pyrethroids with caution. In areas needing residual control Prevathon at 18-20 fl oz or Besiege at 9-10 fl oz works well. If you don't need residual control you can get by with Prevathon at 14 fl oz or Besiege at 7-8 fl oz.

Cotton Insect Guide
  

  Stay safe and have a good weekend everyone, I look forward to seeing you all in person again soon.

Sincerely,

Kate Crumley


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Friday, May 22, 2020

Fleahoppers to Flowers

Howdy,

  I spent the week still looking for fleahoppers and other plant bugs in cotton, but I did see my first flower this week. There's been a couple different species of plant bugs in cotton than I usually see, so feel free to contact me if you have something unusual you would like an ID on. I've heard of some verde plant bugs popping up as well. There are still aphids in some fields across all three counties.

  In Jackson county I found 20% fleahoppers in my field near El Toro, 20% near Vanderbilt, 28% near La Salle, and 26% near the county line off 35. In Matagorda county I found 9% in a field near Tidehaven school, 6% near Tin Top, and 24% near Palacios. In Wharton county I found 11% near Egypt, 2% at Elm Grove, 0%, 4%, 6% at three fields and 11% in a 4th field near the fairgrounds, 0 in one field in the Blue Creek area, 15% in another near Blue Creek, 5% in Danavang, and 0% in a field close to the airport.


Aphids on CottonPhoto: Kate Crumley
Cotton Fleahopper Adult
Kate Crumley
  Cotton fleahopper numbers are rising in some places this week, and with squaring under way in many fields, we'll be needing to keep a closer eye out for this pest. 

  Fleahopper feeding will cause squares to drop. Plants can recover for and compensate for some square loss, but the threshold for fleahoppers is 15-25 per 100 plants. I check for fleahoppers by inspecting the plant terminals once they start squaring. I look at 25 plants per stop in the field, usually checking 100 plants total in an 80-100 acre field, more if the field is larger. Fleahopper nymphs can be close to the size of aphids, but look like smaller versions of the adults without wings, and are much more mobile than aphids.

  The threshold for cotton aphids is 50 aphids per leaf, and if you see the aphid mummies in the field, that's a good thing. Parasitoid wasps lay eggs in the aphids, and the aphid forms a mummy while the wasp larvae pupates inside. These wasps, lady beetles, and lacewings all can make a dent in aphid numbers. Treatment for aphids is very rarely justified since the numbers need to be so high before they can cause an economic problem. If you do decide to treat for aphids, do not use a pyrethroid. Pyrethroids are non specific, and kill predatory insects as well, but aphids will bounce back quickly due to their high reproductive rate. 

  The chart below contains insecticide suggestions from cottonbugs.tamu.edu (also a good resource) for reference if you have fleahoppers at the action threshold.



  Next week I am going to be looking for bollworms in the cotton with flowers. To scout for cotton bollworms I use the terminal and square inspection method, as well as making some full plant checks. I make about four stops in a field, more if the field is larger than 100 acres. At each stop, I look at 25 plant terminals, checking the upper third of the plant for caterpillars and eggs. I also pull 25 half grown or larger green squares to bolls and look for bollworm damage. This week I was finding moths flying in almost every field I was in. Egg lay has been fairly light most of this week with an increase in the last two days. I would like to note that while egg lay in the upper third of the cotton plant is typical, I have seen and have talked to consultants finding egg lay near the bottom of the plants. When documenting egg lay, if I find more than one on a leaf, I only count it as one. This caterpillar is highly cannibalistic, and generally only one caterpillar will result from eggs too near each other. The few caterpillars I have seen were very small, likely had only molted once, and were in the crescent area of Wharton county. The economic threshold for bollworms is 6% damaged bolls with live caterpillars present. In areas like ours on the upper gulf coast with documented Bt failures, the threshold for eggs on single and dual gene cotton is 20% (20 plants out of 100 with at least one egg). If you're finding bollworms in cotton or in corn, especially in viptera fields, please give me a call.
Cotton Insect Guide
  The current A&M recommendation is to use pyrethroids with caution. In areas needing residual control Prevathon at 18- 20 fl oz or Besiege at 9- 10 fl oz works well. If you don't need residual control you can get by with Prevathon at 14 fl oz or Besiege a 7- 8 fl oz. 
Cotton Insect Guide
  In April there was a sighting of a kudzu bug in Cherokee county, and this was the first documented sighting of this pest in Texas. Kudzu bugs have been a problem in soybeans in Georgia, so keep an eye out for this insect in soybeans and in gardens. There is more information on this insect available at https://citybugs.tamu.edu/2020/04/20/kudzu-bug-in-texas/. Let me know if you find this insect, and I'll be looking around as well.

   This week we recieved more information on our agency prociding training for the CARES Act. This includes information on programs available for ag producers. This link has the news release for that information: https://wharton.agrilife.org/2020/05/22/agrilife-provides-cares-act-training-and-outreach-for-ag-producers-affected-by-covid-19/

 If you have any questions feel free to contact me. Stay safe everyone!

Sincerely,

Kate Crumley

For More Information:

 Cotton Insect Guide


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Friday, May 15, 2020

Fleahoppers


Howdy,

  I spent the week still looking for fleahoppers and other plant bugs in cotton. There's been a couple different species of plant bugs in cotton than I usually see, so feel free to contact me if you have something unusual you would like an ID on. I've heard of some verde plant bugs popping up as well. There are still low numbers of aphids in most fields, but nowhere that warrants treatment. I am hoping after this weekend the rain will be hard on our aphids and will foster some disease in those populations. 

  In Jackson county I found no fleahoppers in my field near El Toro, 4% near Vanderbilt, 0 near La Salle, 1% near the county line off 35 in one, and 9% in another off 35 near the county line. In Matagorda county I found 1% in a field near Tidehaven school, 0 near Tin Top, and 4 near Palacios. In Wharton county I found 0 near Egypt, 0 at Elm Grove, 0 at three fields and 6% in a 4th field near the fairgrounds, 0 in one field in the Blue Creek area, 0 in Danavang, and 0% in a field close to the airport.


Aphids on CottonPhoto: Kate Crumley
Cotton Fleahopper Adult
Kate Crumley
  Cotton fleahopper numbers are rising in some places this week, and with squaring under way in many fields, we'll be needing to keep a closer eye out for this pest. 
  Fleahopper feeding will cause squares to drop. Plants can recover for and compensate for some square loss, but the threshold for fleahoppers is 15-25 per 100 plants. I check for fleahoppers by inspecting the plant terminals once they start squaring. I look at 25 plants per stop in the field, usually checking 100 plants total in an 80-100 acre field, more if the field is larger. Fleahopper nymphs can be close to the size of aphids, but look like smaller versions of the adults without wings, and are much more mobile than aphids.
 The threshold for cotton aphids is 50 aphids per leaf, and if you see the aphid mummies in the field, that's a good thing. Parasitoid wasps lay eggs in the aphids, and the aphid forms a mummy while the wasp larvae pupates inside. These wasps, lady beetles, and lacewings all can make a dent in aphid numbers. Treatment for aphids is very rarely justified since the numbers need to be so high before they can cause an economic problem. If you do decide to treat for aphids, do not use a pyrethroid. Pyrethroids are non specific, and kill predatory insects as well, but aphids will bounce back quickly due to their high reproductive rate. 


  The chart below contains insecticide suggestions from cottonbugs.tamu.edu (also a good resource) for reference if you have fleahoppers at the action threshold.
  In April there was a sighting of a kudzu bug in Cherokee county, and this was the first documented sighting of this pest in Texas. Kudzu bugs have been a problem in soybeans in Georgia, so keep an eye out for this insect in soybeans and in gardens. There is more information on this insect available at https://citybugs.tamu.edu/2020/04/20/kudzu-bug-in-texas/. Let me know if you find this insect, and I'll be looking around as well.

  This week I had a few more phone calls with questions on asian giant hornets. If you would like more information, check out this website on the giant asian hornets, and this post on the native Texas insects that look similar.

If you have any questions feel free to contact me. Stay safe everyone!

Sincerely,

Kate Crumley

For More Information:



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Friday, May 8, 2020

Fleahoppers


Howdy,

  This week I've been looking for fleahoppers and other plant bugs in cotton. There's been a couple different species of plant bugs in cotton than I usually see, so feel free to contact me if you have something unusual you would like an ID on. I've heard of some verde plant bugs popping up as well. I have been seeing low numbers of aphids in most fields, but nowhere that warrants treatment. 

  In Jackson county I found 18% fleahoppers in my field near El Toro, 6% near Vanderbilt, 0 near La Salle, 0 near the county line off 35 in one, and 8% in another off 35 near the county line. In Matagorda county I found 0 in a field near Tidehaven school, 2% near Tin Top, and 0 near Palacios. In Wharton county I found 2% near Egypt, 0 at Elm Grove, 0 at three fields and 2.6% in a 4th field near the fairgrounds, 0 in two fields in the Blue Creek area, and 10% in a field close to the airport.
Aphids on CottonPhoto: Kate Crumley
Cotton Fleahopper Adult
Kate Crumley
  Cotton fleahopper numbers are rising in some places this week, and with squaring under way in many fields, we'll be needing to keep a closer eye out for this pest. 
  Fleahopper feeding will cause squares to drop. Plants can recover for and compensate for some square loss, but the threshold for fleahoppers is 15-25 per 100 plants. I check for fleahoppers by inspecting the plant terminals once they start squaring. I look at 25 plants per stop in the field, usually checking 100 plants total in an 80-100 acre field, more if the field is larger. Fleahopper nymphs can be close to the size of aphids, but look like smaller versions of the adults without wings, and are much more mobile than aphids.
 The threshold for cotton aphids is 50 aphids per leaf, and if you see the aphid mummies in the field, that's a good thing. Parasitoid wasps lay eggs in the aphids, and the aphid forms a mummy while the wasp larvae pupates inside. These wasps, lady beetles, and lacewings all can make a dent in aphid numbers. Treatment for aphids is very rarely justified since the numbers need to be so high before they can cause an economic problem. If you do decide to treat for aphids, do not use a pyrethroid. Pyrethroids are non specific, and kill predatory insects as well, but aphids will bounce back quickly due to their high reproductive rate. 


  The chart below contains insecticide suggestions from cottonbugs.tamu.edu (also a good resource) for reference if you have fleahoppers at the action threshold this upcoming week.
This past week we had an online program on the Prevention of Plastic Contamination in Cotton. If you would like to see this seminar, it's available online at https://www.youtube.com/watch?v=5Pja_HbMElA.

   In April there was a sighting of a kudzu bug in Cherokee county, and this was the first documented sighting of this pest in Texas. Kudzu bugs have been a problem in soybeans in Georgia, so keep an eye out for this insect in soybeans and in gardens. There is more information on this insect available at https://citybugs.tamu.edu/2020/04/20/kudzu-bug-in-texas/. Let me know if you find this insect, and I'll be looking around as well.

   Most of you have probably seen the news about the murder hornets as well. These are unlikely to make it to Texas any time in the near future if at all. If you would like more information, check out this website on the giant asian hornets, and this post on the native Texas insects that look similar.

 If you have any questions feel free to contact me. Stay safe everyone!

Sincerely,

Kate Crumley

For More Information:
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Friday, May 1, 2020

Fleahoppers and Hail



Hail Damaged Cotton
Photo: Ben Crumley
Howdy,

   I hope everyone around got the rain they needed this week, and hope you get it soon if not. I know a few places got hail along with our much needed rainfall. If you did get hail, if the growth point wasn't damaged the cotton will very likely bounce back. If you've got stand reduction or severe hail damage, fields can still be considered viable with stand counts as low as 13,000 to 26,000 plants per acre, as long as they are fairly evenly spaced. Damage to the growth point due to hail can result in cotton with multiple main stems rather than one dominant stem. The cotton will wind up without apical dominance, and can have a more bush like appearance with multiple main stems.

   Some of our younger cotton and replanted cotton is still susceptible to thrips damage, and will be until they have 5 true leaves.

   Thrips are a small (about 1/15") light tan or straw colored insect with a punch and suck type mouthpart and asymmetrical mandibles. They punch a hole with one side, then siphon the juice out with the other. They feed one plant cell at a time, and march along punching and sucking as they go. The adults are winged, can travel short distances on their own, and can be carried by a breeze for a fair distance. Larvae hide on the underside of the leaves, often close to the leaf veins, as well as in the terminal of the plant. Feeding damage for this insect causes the leaves to crinkle and curl, and often looks silvery when examined. Thrips feeding can cause delays in plant maturity and eventual yield reduction.
Western Flower Thrips Adult
Photo: Kate Crumley
  While the insects are visible to the naked eye and scouting can be done just by examining the plant, it is easy to miss some of the smaller larvae. Smacking a cotton plant around on the inside of a cup will knock them off and can make them easier to count. This video Blayne Reed put together has techniques for scouting thrips as well. Cotton with a neonicotinoid seed treatment is usually safe from thrips for about 2-3 weeks after emergence. Seedlings in a sandier soil will lose the effects of a seed treatment more quickly than those in heavier clay soils. Rainfall can also impact how long the seed treatments are effective, the more it rains the shorter the amount of time the seed treatment stays effective. 
Thrips Feeding Damage
Photo: Kate Crumley
   The economic threshold for thrips is one thrips per true leaf of the plant until the 5th true leaf stage. Once the plant reaches this stage, treatment for thrips is rarely justified. Check out the cotton insect guide at this website for more information.

Aphids on Cotton
Photo: Kate Crumley
  The threshold for cotton aphids is 50 aphids per leaf, and if you see the aphid mummies in the field, that's a good thing. Parasitoid wasps lay eggs in the aphids, and the aphid forms a mummy while the wasp larvae pupates inside. These wasps, lady beetles, and lacewings all can make a dent in aphid numbers. Treatment for aphids is very rarely justified since the numbers need to be so high before they can cause an economic problem. If you do decide to treat for aphids, do not use a pyrethroid. Pyrethroids are non specific, and kill predatory insects as well, but aphids will bounce back quickly due to their high reproductive rate. 
Cotton Fleahopper Adult
Kate Crumley

  Cotton fleahopper numbers are rising in some places this week, and with squaring under way in many fields, we'll be needing to keep a closer eye out for this pest. 

  Fleahopper feeding will cause squares to drop. Plants can recover for and compensate for some square loss, but the threshold for fleahoppers is 15-25 per 100 plants. I check for fleahoppers by inspecting the plant terminals once they start squaring. I look at 25 plants per stop in the field, usually checking 100 plants total in an 80-100 acre field, more if the field is larger. Fleahopper nymphs can be close to the size of aphids, but look like smaller versions of the adults without wings, and are much more mobile than aphids.
  The chart below contains insecticide suggestions from cottonbugs.tamu.edu (also a good resource) for reference if you have fleahoppers at the action threshold this upcoming week.
  If you have any questions feel free to contact me. Wash your hands and stay safe everyone. I look forward to getting to see some of you in person again soon!

Sincerely,

Kate Crumley

For More Information:


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