Yesterday, while waiting for my field day stop to begin at the ISU Northeast Research Farm, I noticed a bright green insect land on my leg. At first glance, I thought it was the threecornered alfalfa hopper (Photos 1 and 2). I’ve never seen one in real life and was surprised to see it in northeastern Iowa (and what good luck to land on me!). It is a frequent soybean and alfalfa pest in the south but my lab has never collected it during all my sampling in soybean since 2009. Back in the office today, I tried to confirm the species of this beautiful bug. After a little searching online (thanks, BugGuide!) and getting a closer look with a microscope, I think it is buffalo treehopper (Photo 3).
Threecornered alfalfa hopper nymphs and adults use their piercing-sucking stylets to feed. Repeated piercing in the same area of the main stem generates a swollen area and can result in a girdled effect, causing the stem to lodge and break off. The buffalo treehoppers are not considered field crop pests, and feed on black locust, elm, goldenrod and willow.