Texas A&M Agrilife Extension Logo

Texas A&M Agrilife Extension Logo

Friday, July 10, 2020

Cracked Bolls

Howdy,

  Most of our cotton is wrapping up around here, there's open bolls scattered around, and the corn and milo is getting harvested. Cutout occurs when cotton is 5 Nodes Above White Flower (NAWF), and at 350 degree days (DD60) past cutout we can stop worrying about plant bugs and bollworms. We can stop worrying about stink bugs at 450 DD60 past cutout, so keep that in mind while scouting and if you are considering treatment. Most of the cotton in the Wharton, Jackson, and Matagorda area is past concern for pest pressure. The bolls they are feeding on past this point are bolls that will not reach maturity by harvest anyway, as the ones that are going to be harvested have grown too hard for them to feed on.

DD60 since cutout:











  If you're still under 450 DD60 since cutout and are looking 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
Photo: Kate Crumley


Carpal Wall Warts from Stink Bug feeding damage
Photo: Kate Crumley


  If your cotton is still under 350 DD60 since cutout and susceptible, bollworms 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. The eggs of this insect are small and white, turning brown as they get closer to hatching. The caterpillars are also highly cannibalistic, the eggs are normally laid singly, but if you find a couple or more on the same leaf, count it as one.


H. zea eggs
Photo: Kate Crumley

H. zea caterpillar in cotton square
Photo: Kate Crumley

H. zea moth
Photo: 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 at least 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 season the egg lay has been in oddball places. We have been finding eggs in the lower 1/3 of the plant, as well as in bloom tags and bracts on fruit. 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, especially in viptera fields, please give me a call.

H. zea eggs on cotton bloom tag
Photo: Ben Crumley

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. I've seen a few places where folks have gone out with imidacloprid and bifenthrin, but this combination does not work well to kill bollworm eggs in the field or moths.

Cotton Insect Guide
  

  Stephen Biles and I recorded our last audio update for the season this week. If you are interested in checking that out, you find that update here:  https://agrilife.org/lubbock/files/2020/07/Coastal_Bend_7.9.2020.mp3
  On June 17th Laramie Naumann got folks together to film Colorado County's video field day. That video can be found at https://youtu.be/9VB9gZLH9EM.

  Stay safe, and don't get too hot this weekend.

Sincerely,

Kate Crumley


Friday, July 3, 2020

Cutout and Cracked Bolls

Howdy,

  There are a lot of fields blooming out the top, and we found our first cracked boll this week. The cotton crop is wrapping up around here. Cutout occurs when cotton is 5 Nodes Above White Flower (NAWF), and at 350 degree days (DD60) past cutout we can stop worrying about plant bugs and bollworms. We can stop worrying about stink bugs at 450 DD60 past cutout, so keep that in mind while scouting and if you are considering treatment. The bolls they are feeding on past this point are bolls that will not reach maturity by harvest anyway, as the ones that are going to be harvested have grown too hard for them to feed on.

DD60 this season:








  I've seen stink bug damage picking up the last couple of weeks. 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
Photo: Kate Crumley


Carpal Wall Warts from Stink Bug feeding damage
Photo: Kate Crumley


This week's scouting report numbers:

Jackson County

Bollguard 3 near Vanderbilt
16% bollworm eggs
4% small bollworm larvae
18% bollworm damage

Bollguard 2 field near El Toro
14% bollworm eggs

Bollguard 3 field near La Salle
21% bollworm eggs
10% bollworm damage

Matagorda County

Widestrike near Tin Top
1% bollworm eggs
4% bollworm damage

Bollguard 3 field near Tidehaven
10% bollworm eggs
7% bollworm damage

Field with a combination of Bollguard 2 and 3 near Palacios
1% bollworm damage

Widestrike 3 field off 35 near Jackson Matagorda county line
4% bollworm eggs

Widestrike 3 field off 35 near Jackson Matagorda county line
8% bollworm eggs
6% bollworm damage
2% stink bug damage

Wharton County

Widestrike 3 in Blue Creek Area
10% bollworm eggs
8% small worms
12% bollworm damage

Bollguard 2/3 in Blue Creek Area
20% bollworm eggs
3% small worms
9% bollworm damage

Bollguard 2/3 in Blue Creek Area
17% bollworm eggs
3% small worms
11% bollworm damage

Widestrike 3 field near Danavang
6% bollworm eggs
3% bollworm damage
3% bollworm damaged bolls

Bollguard 2 near Crescent
1% bollworm damage
2% stink bug damage

Bollguard 3 near Crescent
12% bollworm eggs
6% bollworm damage

Bollguard 3 near Crescent
4% bollworm eggs

Widestrike 3 near Fairgrounds
6% bollworm eggs
6% small worms
4% bollworm damage
2% bollworm damaged bolls

Bollguard 3 near Egypt
4% bollworm eggs
2% stink bug damage

  Bollworms 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. The eggs of this insect are small and white, turning brown as they get closer to hatching. The caterpillars are also highly cannibalistic, the eggs are normally laid singly, but if you find a couple or more on the same leaf, count it as one.


H. zea eggs
Photo: Kate Crumley

H. zea caterpillar in cotton square
Photo: Kate Crumley

H. zea moth
Photo: 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 at least 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. Recently the egg lay has been in oddball places. We have been finding eggs in the lower 1/3 of the plant, as well as in bloom tags and bracts on fruit. 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, especially in viptera fields, please give me a call.

H. zea eggs on cotton bloom tag
Photo: Ben Crumley

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. I've seen a few places where folks have gone out with imidacloprid and bifenthrin, but this combination does not work well to kill bollworm eggs in the field or moths.

Cotton Insect Guide
  

  Stephen Biles and I recorded another audio update this week. These updates will be going out once a week 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.

  On June 17th Laramie Naumann got folks together to film Colorado County's video field day. That video can be found at https://youtu.be/9VB9gZLH9EM.

  Stay safe, and have a happy 4th of July, yall!

Sincerely,

Kate Crumley


Friday, June 26, 2020

Bugs and Bollworms

Howdy,

  I am still seeing a few different plant bug species around, in cotton as well as other crops, but we should be able to stop worrying about damage from these plant bugs in cotton soon. Once bolls get larger and we reach 350 degree days (DD60) past 5 Nodes Above White Flower (NAWF), we can stop scouting for plant bugs. Most of the cotton in my scouting program is between 6 and 3 NAWF.

  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/

  I have seen stink bugs in cotton this year, damage thus far has been low, but some locations have needed treatment. 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
Photo: Kate Crumley


Carpal Wall Warts from Stink Bug feeding damage
Photo: Kate Crumley
  This week our scouting was limited with the rainfall, but we still picked up worm pressure, and several places we did not get to check were treated before the rain.

Jackson County

Bollguard 3 near Vanderbilt

12% bollworm eggs
4% small bollworm larvae
6% bollworm damage

Bollguard 2 field near El Toro
12% bollworm eggs
2% small bollworm larvae

5% bollworm damage
2% stink bug damage bolls

Matagorda County

Widestrike near Tin Top

8% bollworm eggs

8% bollworm larvae- 6% large, 2% small
8% bollworm damage squares
4% bollworm damaged bolls



Bollguard 3 near Jackson Matagorda county line on 35

8% bollworm eggs
6% small bollworm larvae
7% bollworm damage
1% stink bug damaged small boll


Widestrike 3 Near Jackson Matagorda county line on 35

8% bollworm eggs
4% small bollworm larvae

8% bollworm damage


Field with a combination of Bollguard 2 and 3 near Palacios

5% bollworm eggs
0% bollworm larvae
8% bollworm damage
4% stink bug damaged small bolls

  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. The eggs of this insect are small and white, turning brown as they get closer to hatching. The caterpillars are also highly cannibalistic, the eggs are normally laid singly, but if you find a couple or more on the same leaf, count it as one.


H. zea eggs
Photo: Kate Crumley

H. zea caterpillar in cotton square
Photo: Kate Crumley

H. zea moth
Photo: 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 at least 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. Recently the egg lay has been in oddball places. We have been finding eggs in the lower 1/3 of the plant, as well as in bloom tags and bracts on fruit. 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.

H. zea eggs on cotton bloom tag
Photo: Ben Crumley

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. I've seen a few places where folks have gone out with imidacloprid and bifenthrin, but this combination does not work well to kill bollworm eggs in the field or moths.

Cotton Insect Guide
  

  Stephen Biles and I recorded our fourth audio update this week. These updates will be going out once a week 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.

DD60 this season:








If you're looking for information on dicamba check out:





  Stay dry and have a good weekend everyone!

Sincerely,

Kate Crumley


Friday, June 19, 2020

Bollworms and Stink Bugs

Howdy,

  I am still seeing a few different plant bug species around, in cotton as well as other crops, but we should be able to stop worrying about damage from these plant bugs in cotton soon. Once bolls get larger and we reach 350 degree days (DD60) past 5 Nodes Above White Flower (NAWF), we can stop scouting for plant bugs. Most of the cotton in my scouting program is between 9 and 5 NAWF.

  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/

  Lygus bugs will also 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
Photo: Kate Crumley
Lygus Bug adult
Photo: Kate Crumley
Chart from Cotton Insect Guide

  I have seen few stink bugs in cotton this year, but damage is picking up. 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
Photo: Kate Crumley


Carpal Wall Warts from Stink Bug feeding damage
Photo: Kate Crumley
  We've picked up a few eggs and bollworms in fields this week. In Wharton county we picked up 0% eggs and 8% damaged squares in a field near the fairgrounds, 8% eggs with 6% small worms and 10% damaged squares, 6% eggs and 8% damaged squares, and 21% eggs and 4% damaged squares in another. In the blue creek area we found 15% eggs with 3% damaged squares, 9% eggs with 1% small worms and 4% damaged squares, and 0% eggs with 4% damaged squares in another. Near Danavang we found 4% eggs and 3% small worms with 8% damage. Near Elm Grove we picked up 11% eggs with 3% small worms and 7% damage, near Egypt we found 6% eggs with 2% small worms and 4% damaged squares. There were 20% eggs, 4% small worms, and 8% damaged squares in a field near the airport.

  In Jackson county we found 2% eggs in a field near El Toro with 2% damaged squares, 6% eggs with 2% small worms and 6% damaged squares near Vanderbilt, and 22% eggs with 6% damaged squares near La Salle. In one field near the county line off 35 we picked up 3% eggs with 1% fruit damage, and 3% stink bug damage. In the other field near there we found 5% eggs and 4% damaged squares and 3% stink bug damage.

  In Matagorda county we found 3% eggs with 4% small worms and 13% damaged fruit at Tin Top, 7% eggs with 4% small worms and 7% damaged squares near Tidehaven, and 4% eggs with 1% small worms and 3% damaged fruit near Palacios.

  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. The eggs of this insect are small and white, turning brown as they get closer to hatching. The caterpillars are also highly cannibalistic, the eggs are normally laid singly, but if you find a couple or more on the same leaf, count it as one.


H. zea eggs
Photo: Kate Crumley

H. zea caterpillar in cotton square
Photo: Kate Crumley

H. zea moth
Photo: 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. I've seen a few places where folks have gone out with imidacloprid and bifenthrin, but this combination does not work well to kill bollworm eggs in the field.

Cotton Insect Guide
  

  This week I was able to make a few checks in sorghum. We found moderate numbers of rice stink bugs and a few headworms in the field, as well as a slight increase in sugarcane aphid numbers from last week. None of the insects were over threshold in the fields I looked at, but in places headworm and stink bug numbers have been high. If you've got high numbers of sugarcane aphids, give me a call.



  Stephen Biles and I recorded our third audio update this week. These updates will be going out once a week 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.

DD60 this season:




If you're looking for information on dicamba check out:





  Stay safe and have a good weekend everyone!

Sincerely,

Kate Crumley