Cotton maturity ranges up to squaring cotton. Once cotton begins to square, fields should be monitored for cotton fleahopper. Cotton fleahoppers can cause yield loss or delay harvest by feeding on small squares; causing them to fall off the plant. Once a square is the size of a match head, it is no longer susceptible to being lost as a result of fleahopper feeding.
You must be especially observant to find the small nymphs of this pest. They nymphs are pale green, as small or smaller than cotton aphids and move rather quickly. Monitor fields by carefully inspecting 5-10 plants at 5-10 spots per field. Larger fields require more locations to check.
The cotton varieties we plant today have a great ability to compensate for early fruit loss. I do not think the first three squares on the plant are worthy of protection from cotton fleahoppers. Recent research has demonstrated early fruit is less important to harvestable yield than in the past when late season control of weevils and worms was a considerable challenge.
Boll weevil eradication and the introduction of Bt cotton varieties made the protection of the early fruit less important. Now the primary reason for an early crop is to avoid adverse weather at harvest time.
I suggest waiting until the cotton plants have three fruiting sites to initiate control of cotton fleahoppers when economic thresholds are exceeded. In South and East Texas, a good economic threshold for cotton fleahopper is 15 per 100 plants.
Cotton Pest Management App
There is a new Cotton Pest Management App for the iPhone. Search for “Texas Cotton Pests” at the app store.