Fleahoppers and Bollworms

Howdy,

Next Thursday we are hosting a Cotton Scout School at 8:00 am at the Jackson County Services Building in Edna, TX. It's $10 per person to attend, and you can get 2 TDA IPM CEUs. Let us know if you'll be able to attend! Please see the flyer below or give our office a call for more information.

This week we got a good rain across most of the area. Our older cotton is starting to bloom, the soybeans are blooming, and the oldest sorghum is starting to color. The thrips I picked up in soybeans last week were tobacco thrips, and those numbers have dropped significantly with our recent rains.

In sorghum we need to be scouting for sugarcane aphid, I've picked it up in sorghum in all three counties in light numbers now. If it's blooming, we need to look for sorghum midge. Here are some links for just sugarcane aphid, and a more recently updated guide for sorghum insect management. Here are links to the threshold calculators for sorghum midge, rice stink bug, and sorghum headworm. 

Sugarcane Aphids in Sorghum
Kate Crumley

Aphids are still in the cotton, and have been fairly heavy depending on the location. We are picking up fleahoppers, and need to be scouting anything with squares carefully for those. This week we started picking up bollworm eggs, and will be shifting from looking for fleahoppers to looking for bollworms as the fields start to bloom. Below is my scouting information for the week of 5/27/2022. The fields we missed this week were due to rain.

Cotton Aphid
Kate Crumley

The threshold for cotton aphids is 50 aphids per leaf, and if you see aphid mummies in the field (tan or black dry and unmoving aphids), that's a good thing. Parasitoid wasps lay eggs in the aphids, and the aphid forms a mummy while the wasp larvae is pupating inside. These wasps, lady beetles, and lacewings can knock back aphid populations. Treatment for aphids is rarely justified, but if you do decide to treat for aphids, do not use a pyrethroid. Pyrethroids and organophosphates are broad spectrum, and kill beneficial insects as well as your target insect, but pests like aphids bounce back much quicker than their predators do. Their high reproductive rate will allow their numbers to soar after a broad spectrum insecticide application kills all their predators.

Aphid Mummies on Cotton
Kate Crumley

Cotton Fleahopper Adult
Kate Crumley

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 in the upcoming weeks.

We started picking up bollworm eggs in cotton this week. We found very few, and I've had moderate moth numbers in our traps as well. 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. They are already in the corn, below is a photo of a caterpillar I pulled from dual gene corn. As the corn matures, the next generation of bollworm eggs will be laid in cotton. I start looking for bollworm eggs in cotton when that field starts blooming.

H. zea Larvae
Kate Crumley

Our Bt traits overlap across corn and cotton. If the caterpillars survive the traits on corn then as adults fly to cotton to lay eggs, it's likely their offspring will survive the same traits on cotton. Below is a chart showing the overlap of Bt traits between crops and technologies.

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. 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).

H. zea Eggs on Cotton
Kate Crumley

I'd also like to let everyone know that there is an Agricultural Pesticide Waste Collection event happening on Wednesday, June 29th from 8:00 am to 12:00 pm at the Victoria County Pct #4 Yard at 226 Beck Road East, Inez, TX 77968. The flyer for that event is below. For any additional questions on this event, please contact the Victoria County Extension Office at (361)-575-4581.

Please check out our weekly IPM Audio Updates, the website to sign up to receive those is listed below. If you have any questions feel free to contact me either by email or calling the office. Have a good memorial day weekend, everyone!

Sincerely,

Kate Crumley

Check out our weekly IPM Audio Updates

Cotton Insect Management Guide

Development and Growth Monitoring of the Cotton Plant

Fleahoppers and Sugarcane Aphids

Howdy,

We are still dry this week. All of our crops could use the water, although it may be too late for a lot of the corn. Our older cotton is up to match head and 1/3 grown square, and the sorghum is booting to soft dough. 

In sorghum we need to be scouting for sugarcane aphid, I've picked it up in sorghum in all three counties in light numbers now. If it's blooming, we need to look for sorghum midge. Here are some links for just sugarcane aphid, and a more recently updated guide for sorghum insect management. Here are links to the threshold calculators for sorghum midge, rice stink bug, and sorghum headworm. 

Sugarcane Aphids in Sorghum
Kate Crumley

In soybeans I started seeing some thrips infestations, I've collected some for identification and will keep everyone updated. Stephen Biles did a test on that a few years ago, and the results of that can be found here. The general estimated threshold for those is 10 thrips per leaflet (not trifoliate), and I've not seen them in that high of numbers yet. I've seen the thrips mostly on the top of the older leaves on soybeans.

Thrips Injury on Soybeans
Kate Crumley

Thrips Injury on Soybeans
Kate Crumley

Thrips on Soybeans
Kate Crumley

Aphids are still in the cotton, but I've been picking up 1 or 2 plants covered in them, and none in the other 25-50 plants checked. We are picking up fleahoppers, and need to be scouting anything with squares carefully for those. Below is my scouting information for the week of 5/20/2022.

Cotton Aphid
Kate Crumley

The threshold for cotton aphids is 50 aphids per leaf, and if you see aphid mummies in the field (tan or black dry and unmoving aphids), that's a good thing. Parasitoid wasps lay eggs in the aphids, and the aphid forms a mummy while the wasp larvae is pupating inside. These wasps, lady beetles, and lacewings can knock back aphid populations. Treatment for aphids is rarely justified, but if you do decide to treat for aphids, do not use a pyrethroid. Pyrethroids and organophosphates are broad spectrum, and kill beneficial insects as well as your target insect, but pests like aphids bounce back much quicker than their predators do. Their high reproductive rate will allow their numbers to soar after a broad spectrum insecticide application kills all their predators.

Aphid Mummies on Cotton
Kate Crumley

Spider mite populations rarely get high enough to treat, as they thrive in drier climates and we tend to be fairly humid. Treatment is justified when spider mites are causing visible defoliation.

Spider Mites on Cotton
Kate Crumley

Cotton Fleahopper Adult
Kate Crumley

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 in the upcoming weeks.

I'd also like to let everyone know that there is an Agricultural Pesticide Waste Collection event happening on Wednesday, June 29th from 8:00 am to 12:00 pm at the Victoria County Pct #4 Yard at 226 Beck Road East, Inez, TX 77968. The flyer for that event is below. For any additional questions on this event, please contact the Victoria County Extension Office at (361)-575-4581.

Please check out our weekly IPM Audio Updates, the website to sign up to receive those is listed below. If you have any questions feel free to contact me either by email or calling the office. Have a good weekend, and I hope we get some rain!

Sincerely,

Kate Crumley

Check out our weekly IPM Audio Updates

Cotton Insect Management Guide

Development and Growth Monitoring of the Cotton Plant

Squaring Cotton and Fleahoppers

Howdy,

We are still dry this week. All of our crops could use the water, although it may be too late for a lot of the corn. The last two weeks I've seen a lot of corn watered, and some of our growers have started watering cotton.  Our older cotton is up to match head and even 1/3 grown square, and the sorghum is starting to head out and bloom.

Squaring Cotton
Kate Crumley

Thrips numbers have been fairly low in the cotton still susceptible to damage, aphid numbers have dropped, and I'm no longer seeing spidermites to speak of in cotton. We are picking up fleahoppers, and need to be scouting anything with squares carefully for those. Below are charts with my scouting information for the week of 5/13/2022.

Thrips are a small (about 1/15") light tan, straw, to brown or black 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 typically feed on one plant cell at a time, and march along punching and sucking as they go. The adults are winged, and can travel short distances on their own, or 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. This week I found most hiding in the rolled up true leaf in the terminal. Feeding damage for this insect causes cotton leaves to crinkle and curl, and often looks silvery when examined. Thrips feeding can cause delays in plant maturity, which can lead to yield reduction.

Western Flower Thrips
Kate Crumley

Tobacco Thrips
Kate Crumley

The insects are visible to the naked eye and scouting can be done 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. Cotton with a neonicotinoid seed treatment is usually safe from thrips for about 2-3 weeks after planting, depending on weather and soil types. Seedlings in sandier soil will typically lose the effect of seed treatments more quickly than those in heavier clay soils. Heavy rainfall can also reduce the amount of time a treatment is effective, while not enough water can impact the plant's uptake of the treatment and also cause a reduction in efficacy.

Thrips Damage
Kate Crumley

The economic threshold for thrips is 1 thrips per true leaf until the 5th true leaf stage. Once the plant reaches this stage, treatment for thrips is rarely justified.

Cotton Aphid
Kate Crumley

The threshold for cotton aphids is 50 aphids per leaf, and if you see aphid mummies in the field (tan or black dry and unmoving aphids), that's a good thing. Parasitoid wasps lay eggs in the aphids, and the aphid forms a mummy while the wasp larvae is pupating inside. These wasps, lady beetles, and lacewings can knock back aphid populations. Treatment for aphids is rarely justified, but if you do decide to treat for aphids, do not use a pyrethroid. Pyrethroids and organophosphates are broad spectrum, and kill beneficial insects as well as your target insect, but pests like aphids bounce back much quicker than their predators do. Their high reproductive rate will allow their numbers to soar after a broad spectrum insecticide application kills all their predators.

Aphid Mummies on Cotton
Kate Crumley

Spider mite populations rarely get high enough to treat, as they thrive in drier climates and we tend to be fairly humid. Treatment is justified when spider mites are causing visible defoliation.

Spider Mites on Cotton
Kate Crumley

Cotton Fleahopper Adult
Kate Crumley

I am seeing fleahoppers this week, and we were picking up nymphs in addition to adults.

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 in the upcoming weeks.

I'd also like to let everyone know that there is an Agricultural Pesticide Waste Collection event happening on Wednesday, June 29th from 8:00 am to 12:00 pm at the Victoria County Pct #4 Yard at 226 Beck Road East, Inez, TX 77968. The flyer for that event is below. For any additional questions on this event, please contact the Victoria County Extension Office at (361)-575-4581.

Please check out our weekly IPM Audio Updates, the website to sign up to receive those is listed below. If you have any questions feel free to contact me either by email or calling the office. Have a good weekend everyone!

Check out our weekly IPM Audio Updates

Plant Population Evaluation

Making Replant Decisions in Cotton

Cotton Insect Management Guide

Development and Growth Monitoring of the Cotton Plant

Cotton Squaring Soon

Howdy,

We've been off to a relatively cool and very windy start, and nearly everywhere still needs rain, but most of our cotton is up, and the earliest planted will probably be squaring as early as next week. The corn and sorghum is looking dry and we are seeing some yellow sugarcane aphids in sorghum, both in low numbers, and most folks were watering this week. I have been looking for sorghum aphids (renamed from sugarcane aphids) a bit in some of the johnson grass on the edges of fields, but I have not picked any up yet in the spots I've looked.

Wind Blown Cotton
Kate Crumley

Cotton stands can be impacted by some of the weather we've had recently, but stands as low as 13,000 to 26,000 plants per acre can still be viable as long as the plants are fairly evenly spaced out, with at least 1 plant per foot of row.

Thrips numbers in cotton have dropped this week compared to last week, most locations have treated for them, and I didn't see any spider mites this week. Aphid numbers are still low as well. I have fields starting to square, and some of the oldest cotton has match head size squares on it, so we are starting to check for fleahoppers. Below are charts with my scouting information for this past week, the week of 5/6/2022.

Thrips are a small (about 1/15") light tan, straw, to brown or black 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 typically feed on one plant cell at a time, and march along punching and sucking as they go. The adults are winged, and can travel short distances on their own, or 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. This week I found most hiding in the rolled up true leaf in the terminal. Feeding damage for this insect causes cotton leaves to crinkle and curl, and often looks silvery when examined. Thrips feeding can cause delays in plant maturity, which can lead to yield reduction.

Western Flower Thrips
Kate Crumley

Tobacco Thrips
Kate Crumley

The insects are visible to the naked eye and scouting can be done 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. Cotton with a neonicotinoid seed treatment is usually safe from thrips for about 2-3 weeks after planting, depending on weather and soil types. Seedlings in sandier soil will typically lose the effect of seed treatments more quickly than those in heavier clay soils. Heavy rainfall can also reduce the amount of time a treatment is effective, while not enough water can impact the plant's uptake of the treatment and also cause a reduction in efficacy.

Thrips Damage
Kate Crumley

The economic threshold for thrips is 1 thrips per true leaf until the 5th true leaf stage. Once the plant reaches this stage, treatment for thrips is rarely justified.

Cotton Aphid
Kate Crumley

The threshold for cotton aphids is 50 aphids per leaf, and if you see aphid mummies in the field (tan or black dry and unmoving aphids), that's a good thing. Parasitoid wasps lay eggs in the aphids, and the aphid forms a mummy while the wasp larvae is pupating inside. These wasps, lady beetles, and lacewings can knock back aphid populations. Treatment for aphids is rarely justified, but if you do decide to treat for aphids, do not use a pyrethroid. Pyrethroids and organophosphates are broad spectrum, and kill beneficial insects as well as your target insect, but pests like aphids bounce back much quicker than their predators do. Their high reproductive rate will allow their numbers to soar after a broad spectrum insecticide application kills all their predators.

Aphid Mummies on Cotton
Kate Crumley

Spider mite populations rarely get high enough to treat, as they thrive in drier climates and we tend to be fairly humid. Treatment is justified when spider mites are causing visible defoliation.

Spider Mites on Cotton
Kate Crumley

Cotton Fleahopper Adult
Kate Crumley

I've seen a few fleahoppers this week, but not in squaring cotton yet. Next week I plan to start checking for fleahoppers in fields with squares.

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 in the upcoming weeks.

Please check out our weekly IPM Audio Updates, the website to sign up to receive those is listed below. If you have any questions feel free to contact me either by email or calling the office. Have a good weekend everyone!

Check out our weekly IPM Audio Updates

Plant Population Evaluation

Making Replant Decisions in Cotton

Cotton Insect Management Guide

Development and Growth Monitoring of the Cotton Plant