Garden fleahopper curiosity

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Bruce MacKellar, Extension Educator in St. Joseph County, brought an unusual sample in this week. Bruce reported a soybean field with what appeared to be spider mite damage, but it was too early and too wet for mite populations to develop. Instead of mites, he observed a fast moving, triangular, black insect hopping on the foliage.

This is garden fleahopper, an insect that resembles a flea beetle – it is small, black and has fat back legs modified for jumping (Photo 1). However, this critter is a true bug, related to other sucking pests such as tarnished plant bug, alfalfa plant bug, leafhoppers, and aphids.

Like other true bugs, fleahoppers suck plant juices, damaging individual plant cells and creating yellowing feeding spots that can resemble spider mite damage (Photo 2). Like aphids, fleahoppers have both winged (Photo 3) and non-winged (Photo 4) adults (the non-winged form was more common in Bruce’s samples.) Unlike aphids, there are both male and female hoppers, and they reproduce by laying eggs. The bright green non-winged juveniles, or nymphs, resemble large aphids, but are fast moving and active.

This insect can build up high populations in alfalfa, and then move to a neighboring crop when the alfalfa is cut. Indeed, Bruce reports that the soybean field was adjacent to a recently-cut alfalfa field. However, fleahopper infestations are rare – this is the first one I’ve ever seen – and damage is not economic. Plants will grow past this early injury.

Photo 1. Garden fleahopper.

Garden fleahopper
Photo 2. Garden fleahopper damage.

Garden fleahopper
Photo 3. Winged adult garden fleahopper.

Garden fleahopper
Photo 4. Non-winged adult garden

Dr. DiFonzo's work is funded in part by MSU's AgBioResearch.

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