Young Vine Decline
Definition - What does Young Vine Decline mean?
Young vine decline is a general term used in viticulture to describe the 9 types of fungi, including Phaeoacremonium and Togninia Minima that attack young grapevines. Young vine decline is also known as black goo, as the sap in the vine turns to a thick dark brown or black in response to the fungi. Young vine decline was identified in 1900 in Italy and has since been found in almost all wine regions, but it rarely affects an entire region or vineyard.
WineFrog explains Young Vine Decline
As the name suggests, young vine decline attacks young vines that are becoming established in the vineyard. Young vines that are becoming established, adjusting to being grafted and being pruned, are more easily susceptible to the infection from fungi than mature, established vines.
The fungus enters the vine at an injury, graft or pruning site. The fungus thrives in vineyards that are not managed properly, with vines planted closely together, and without properly irrigated or fertilized soil.
Young vine decline prevents vine roots from growing and establishing a good foundation for the vine and affects the sap and the woody parts of the vine, with black or dark brown spots visible in a cross section of an infected vine. This damage to the vascular system of the vine makes transporting nutrients very hard, and infected vines will present with wilted and yellowed leaves. Young vine decline only affects grapevines and only affects weakened vines, so while vineyard workers always need to follow sanitary and pruning protocols, they also need to establish healthy vines under the right growing conditions.