This year I have seen low thrips numbers in the fields in the Wharton, Jackson and Matagorda county area. The threshold for thrips is an average of 1 thrips per true leaf until the 5th leaf stage. While leaf cupping and curling can be signs of thrips damage, most of the curling I’ve seen this year was due to wind damage, not thrips.
I saw cotton fleahoppers in every field with squaring cotton this week. The highest population I saw this week was in a field near Palacios, with 45% of plants with fleahoppers. This insect 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.
With the wind we were having it was actually easier to find the adult fleahoppers. They tend to hunker down into the plant instead of taking flight when it’s windy. The nymphs of these insects are quite small, about the size of an aphid. They are 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.
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 below contains insecticide suggestions from cottonbugs.tamu.edu (also a good resource) for reference if you have fleahoppers at the action threshold. Two locations I looked at this week could have considered treatment with a ground rig, but everywhere else I looked for them was too wet. I’d like to note that drowning is not my preferred method for controlling fleahoppers.
I am currently looking for sugarcane aphids in sorghum fields as well. I’ve found them with little difficulty in johnson grass, but have not located them in field in any of my counties yet. If you have some, please let me know and I can confirm their presence in the county for our sugarcane aphid mapping project.
This week I received a couple of phone calls and emails with questions on Texas leaf cutter ants and fire ants. Both these species are currently producing mating flights. For information on biology and management on fire ants check out this website, and for leaf cutter ants check out this one.
We also had a bumper crop of forest tent caterpillars about a month ago, and now there are a bunch of their moths flying around. If you wondered what all the small, fuzzy, tan moths were, now you know- forest tent caterpillars.
If you’re not sure what kind of insect you have, feel free to drop it by the Wharton county office.
I hope everyone stays safe and drier than we are currently anticipating out there. Good luck all, and as always feel free to call or email with any questions or concerns.