The spread of the American grapevine leafhopper is raising concerns among winegrowers in Styria, as more vineyards face infection from Flavescence dorée, a bacterial disease that causes yellowing leaves, shriveled berries, and stunted ripening.
“The only way to combat the disease is by uprooting infected vines,” said University of Graz biologist Gernot Kunz. The leafhopper transmits the bacteria after feeding on an infected vine, with a three-to-four-week incubation period before spreading it further. Worryingly, vines can harbor the disease for years without showing symptoms.
First detected in Klöch in 2004, the pest took a decade to cause visible damage. Kunz noted that high insect densities in private gardens and abandoned vineyards in Graz, where the species was first observed in 2019, are contributing to the problem.
While adult insects can be trapped using artificial lights on warm summer nights, Kunz warned that their ability to travel long distances means reinfestation remains likely.
Source: University of Graz
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