It has been a while since anyone asked me about garden fleahopper in peanut, but this is the time of year when they begin to get noticed. After a couple years with more fleahoppers than “normal”, populations in Georgia peanut fields in 2016 were typically low or nonexistent. We are currently seeing increasing numbers of adult and nymph garden fleahopper in our research plots around Tifton, so I figured now would be a good time to remind folks about the insect and the injury it causes.
Garden fleahoppers (GFH) are small insects that feed by sucking juices from plant leaves. This feeding results in stippling on the leaves that looks a lot like spider mite injury. The undersides of leaves that have been fed on by GFH will have tiny black “tar spots”. We want to be sure not to confuse spider mite injury (which can be a much more serious problem) with fleahopper injury.
Adult GFH come in three forms: short winged females, long winged females, and long winged males. There is no published economic threshold for this insect in peanut, and populations have rarely been high enough to cause much concern. That said, we do not want to ignore GFHs. Some fields were treated in 2015 when defoliation was associated with very heavy infestations. In the past, pyrethroid efficacy against GFH in peanut has been only mediocre. Bryce Sutherland, a graduate student in the UGA Peanut Entomology program, is currently evaluating the activity of several insecticides on GFH in peanut. **2023 UPDATE: Pyrethroid insecticide applications in peanut have been repeatedly shown to cause GFH numbers to increase. The mechanism for this response is not known, but it is very consistent.
If you have questions about this or other insect management issues in peanut, please contact your local UGA County Extension Agent.