Cotton Fleahopper

Pseudatomoscelis seriatus

Adult cotton fleahopper.

If immature squares are turning brown and dropping, the problem could be damage by fleahoppers. If more than 10 to 20 percent of small squares are lost in pre-bloom cotton, the plants should be examined for fleahoppers. Fleahopper are about 1/8 inch long and yellowish-green in color. They have an elongated, oval-shaped body that is slightly flattened over the top, which is typical for most true bugs. Adult fleahoppers have a few dark spots on the upper surface of the back near the rear. Nymphs are pale white to light green, small and appear to be all legs and antennae. There are many generations per year, and populations may build up on alternate hosts such as wooly croton, horsemint, and silverleaf nightshade before cotton is planted, so damaging infestations are more likely where these weeds are abundant. Attempts to control these weeds after cotton plants have emerged may force fleahopper migration into the cotton field.

Although fleahoppers are common in Kansas cotton fields, most populations remain below treatment threshold. Begin scouting for fleahoppers when cotton reaches the six-leaf stage, being aware that adult fleahoppers startle visually and may jump from plants if they see a shadow. During the first three weeks of squaring, the economic threshold is approximately 25 to 40 fleahoppers per 100 terminals with 10 to 15% of squares blasted. Sampling can also be conducted with a drop cloth or sweep net. The drop cloth is placed between the rows and the plants are shaken vigorously over the cloth. Treatment should be considered when one bug is counted for every one to three feet of row examined. With a sweep net, the threshold ranges between 1 and 1½ bugs per 10 sweeps.

Only squares in very early stages are attacked, so if square retention is 75% or greater, the fleahopper population is probably not significant. Because the cotton growing season in Kansas is so short, it is rarely economical to treat fleahoppers in August, or after bloom is well underway. Late-developing squares contribute little to yield and any treatment will kill off beneficial insects, possibly releasing other pests such as bolllworms from biological control. Any such secondary pest resurgence would offset the advantages of protecting later squares from fleahopper damage.

Many potential pests are under biological control in cotton, so whenever significant numbers of fleahoppers are found, choose insecticides that are selective and have the least impact on beneficial arthropods, especially those which require consumption by the insect. Use lower rates and do not try to achieve 100 percent fleahopper control.

Please refer to the most recent Cotton Insect Management Guide for material rates and control options.

Page last updated 5/13/2024 by J.P. Michaud.