Nébih: Early detection can curb golden yellow grape disease

The presence of the pathogen can be confirmed by laboratory testing, but the most characteristic symptoms can also be observed on plantations.

Infection is indicated by the spoon-shaped leaves, triangular drift, yellowing and dying leaves in spots in white wine grape varieties, and redness between the leaf veins in blue grape varieties. The leaves harden like paper and fall off, the shoots do not become woody, the canes thin, become rubbery, and often take on a drooping shape reminiscent of a weeping willow. The clusters do not develop properly, the berries are withered, have a bad taste, and have a low sugar and high acid content. Grape varieties of American origin are often asymptomatic, so the disease can remain hidden.

They added that the pathogen is not capable of spreading independently, and is primarily spread by the American grape cicada. Its individuals can mainly appear on the upper leaves of the shoots, and they need to feed for 7-8 days to develop infectivity. The adult insect is 5-6 millimeters long, light brown-orange in color, the top of its head is slightly pointed, and a black stripe pattern can be seen on its front edge. Since they can be easily confused with other species, laboratory testing is recommended for their identification.

According to the statement, the disease has already affected 15 wine regions, its economic damage is severe, and it seriously threatens grape growing.