Fleahoppers and Verdes

Howdy,

  This week I have seen low thrips numbers and moderate fleahopper 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. If there is a silver looking sheen on the underside of leaves, that can be attributed to thrips.

  I saw cotton fleahoppers in lower numbers than last week in squaring cotton fields this week. The highest population I saw was in a different field near Palacios, close to the Jackson/ Matagorda county line, with 31% of plants with fleahoppers (mostly nymphs) and 1 verde plant bug. 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. This field had not yet been treated. 

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/

In another field near Palacios I found 14% fleahoppers with mostly nymphs present. In Jackson county I found fleahoppers at 2% near El Toro and 3% near Vanderbilt. In Wharton county I found 10% and 1% in the crescent area. One field near the airport I was unable to check due to being treated for 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. 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 Harrell

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.

  

 This week in one of my cotton fields near Elm Grove I noticed a good bit of turned up dirt, especially near one end of the field. Feral hogs churned up the ground and uprooted some of the cotton out there. We don't currently have a set economic threshold for hogs in cotton, but if you're looking for information on this animal check out this website.

 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 Jackson or Matagorda 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.

  Mosquito control is on many people's minds with the recent rains. Check out this publication on backyard mosquito control and this website on insect information and control options.

  If you're not sure what kind of insect you have, feel free to drop it by the Wharton county office.

  Happy Memorial day, everyone!

Sincerely,

Kate

Looking for more information? Check out the Cotton Insect Guide

Need help with weed control? Check out the Weed Management Guide