Which disease weakens growth on young vines and may cause sudden death in hot weather?

Which disease weakens growth on young vines and may cause sudden death in hot weather?

• A. Black Measles (Esca)
• B. Pierce's Disease
• C. Crown Gall
• D. Leafroll Virus

Answer: (A)

Pierce’s Disease is a vascular problem in grapevines caused by Xylella fastidiosa. It clogs water transport in the xylem, causing growth decline, leaf scorch in hot weather, and cane dieback. In young vines, the loss of efficient water movement severely limits growth, and under hot, stressful conditions this can lead to rapid decline or sudden death. Transmission by xylem-feeding insects like sharpshooters helps spread the disease in warm climates, which is why heat accelerates its impact. By comparison, Black Measles (Esca) is a wood-rot complex that typically affects older vines and presents with different symptoms such as irregular foliar changes and wood necrosis, not the quick, heat-triggered collapse seen with Pierce’s Disease. Crown Gall causes galls and stunted growth through a bacterial infection but doesn’t usually produce sudden heat-related vine death. Leafroll Virus causes downward leaf curling and slower vigor loss, without the acute heat-induced collapse.

Pierce’s Disease is a vascular problem in grapevines caused by Xylella fastidiosa. It clogs water transport in the xylem, causing growth decline, leaf scorch in hot weather, and cane dieback. In young vines, the loss of efficient water movement severely limits growth, and under hot, stressful conditions this can lead to rapid decline or sudden death. Transmission by xylem-feeding insects like sharpshooters helps spread the disease in warm climates, which is why heat accelerates its impact.

By comparison, Black Measles (Esca) is a wood-rot complex that typically affects older vines and presents with different symptoms such as irregular foliar changes and wood necrosis, not the quick, heat-triggered collapse seen with Pierce’s Disease. Crown Gall causes galls and stunted growth through a bacterial infection but doesn’t usually produce sudden heat-related vine death. Leafroll Virus causes downward leaf curling and slower vigor loss, without the acute heat-induced collapse.