Agriculture | Reed glasswing cicada causes major damage to fields

Farmers have one more concern: the spread of two bacteria that can cause significant quality losses in potatoes and sugar beets. However, it's a 5- to 9-millimeter-long cicada that spreads the pathogens.

The dark brown to black reed glasswing leafhopper takes its name from its transparent forewings and its original habitat on riparian plants. Sabine Andert, director of the Federal Research Institute for Cultivated Plants in Quedlinburg, describes this as a "completely new situation": "A native insect has left its ecological niche and initially adopted sugar beets as a host plant, then switched to potatoes in 2022." The adaptable leafhopper, with twelve spines on its hind legs, feeds on the sap of its host plant and lays its eggs in the adjacent soil, causing both above- and belowground infestation. It benefits from its symbiosis with bacteria, as these make the plants more digestible.

There are no means available to directly combat the bacteria. Experiments are being conducted with the emergency approval of insecticides, but this alone is insufficient given the months-long cicada flight. The best control methods so far are considered to be a specific crop rotation and a prolonged fallow period until April.

In parts of southern and eastern Germany, damage is already running into the millions. In 2024, 85,000 hectares of sugar beets and 22,000 hectares of potatoes – eight percent of their nationwide cultivation area – were affected. There are no major losses in Brandenburg yet, "but the danger is increasing," the State Farmers' Association reported on Monday. The first major outbreak was spotted in Märkisch-Oderland.