Thursday, July 11, 2019

Texas High Plains Cotton: Keep Watch on the Fleahoppers

This is just a heads up that there have been a few reports of cotton fleahoppers in cotton. Cotton fleahopper adults are pale green to gray-green; nymphs are lighter-colored with reddish eyes. Fleahoppers prefer to feed on small squares (pinhead size) and can cause substantial square loss if present in enough numbers. When scouting for fleahoppers, pay attention to both number of insects in field and the percent square retention especially during the first three weeks of squaring. They typically don’t target large (> matchhead size) squares.  Thus, they are normally concentrated in the top few nodes of the plant. Scout by visually inspecting plant terminals, the top three nodes. Adults are active flyers, but nymphs can be spotted when observed carefully.  
Cotton fleahopper adult (Photo: Salvador Vitanza)
Cotton fleahopper nymph (Photo: Xandra Morris)

Here is a link to a video on how to scout for fleahoppers in cotton.
Use an economic threshold of 25-30 cotton fleahoppers per 100 terminals to determine when treatment is needed. After, first bloom, fleahopper control is rarely justified. Avoid using broad-spectrum insecticides as they can negatively impact beneficial insect populations and cause outbreaks of aphids and bollworms.
Additional information on cotton fleahopper management can be found at: https://agrilifecdn.tamu.edu/lubbock/files/2017/06/Cotton-fleahopper_ENTO073.pdf
FYI – I am also seeing some black fleahoppers in cotton. There isn’t much information available about their impact on cotton—include them along with cotton fleahopper counts and base your treatment decisions taking into account the number of insects present and percent square loss.

Lygus bug (pictures below) numbers have remained sparse so far. But there have been scattered reports of treatment level infestations of lygus bug in few fields. Be alert for lygus but do not confuse other harmless true bugs for it.  

Adult lygus bug (Photo: Pat Porter)
Adult lygus bug