Rhododendron leafhopper

Rhododendron leafhopper (Graphocephala fennahi). This nearly one-cm leafhopper came to continental Europe from North America via England in the second half of the last century. The rhododendron leafhopper is the spreader of the fungus Pycnostysanus azaleae that causes rhododendron blight.
The larvae live off the sap of rhododendrons. The adult leafhopper also has the juices of other plants on its menu. The leafhoppers are active from mid-summer through October. The leafhopper lays its eggs in flower buds in August, infecting the flower bud with the fungus.
In spring, the eggs hatch and the greenish larvae nest on the underside of young leaves and suck leaf sap. In the process, they produce honeydew that can become covered in sooty mold under humid conditions.