A new method to monitor eggs of the Grape Leafhopper (Empoasca vitis) in grapevine leaves

The Grape Leafhopper (Empoasca vitis) deposits its eggs in the veins and le af stalks of grapevine leaves. These eggs fluoresce strongly from within th e intact leaf tissue under a direct light fluorescence at 450-490 nm (blue light), but not at 340-380 nm (UV-light); thus, the eggs can be monitored q uantitatively under blue light excitation. With a stereo microscope under h alogen light, however, only a small fraction of the eggs observed under the fluorescence microscope could be detected, almost exclusively egg larvae w ith red eye spots, about ready to hatch. The eggs are preferentially deposi ted in veins of Ist: or 2nd order or in leaf stalks, while small veins are avoided.