You should be talking about grape black wood disease, named after the immature part of the diseased grape turns black in autumn. Its typical symptoms are oval or round necrotic spots on the epidermis of grapevine, which are bubble-shaped, with scattered protrusions, yellow-brown in the early stage, black-brown in the late stage, and finally the grapevine turns black. Another symptom of this disease is yellowing and curling of leaves. The types of yellowing are different and vary with grape varieties. Sometimes it turns yellow-brown or brown between the first and second veins of leaves, and mesophyll is necrotic; Sometimes, the veins are yellow and necrotic, similar to the symptoms of veins; Sometimes it will show that the leaves similar to golden yellow disease turn yellow. The diseased leaves of red grape varieties are red, the leaves roll back, the surface has metallic luster, and the leaves are hard and brittle, which can cause irregular fruit size and poor coloring.

Control method: 1. Propagation and cultivation of virus-free seedlings. Breeding and cultivating virus-free seedlings is the most fundamental measure to control grape black wood disease. When cultivating virus-free seedlings, we mainly grasp the following steps: ① Cultivate rootstocks through planting. ② Heat treatment between stems and virus removal by tissue culture. ③ The virus was identified by enzyme-linked immunosorbent assay or reverse transcription polymerase chain reaction and indicator plant detection. (4) Establish a virus-free mother tree orchard and provide non-toxic propagation materials. ⑤ Establish virus-free seedlings, quickly cultivate virus-free seedlings through grafting and cutting, and supply them to production in time. 2. Plant quarantine. When transporting seedlings and propagation materials in disease-free areas or newly-built vineyards, we should attach great importance to or strictly implement the quarantine system to avoid the introduction and spread of viruses. 3. Eliminate central disease strains. Careful observation should be made in the vineyard, the diseased plants should be pulled out and destroyed in time, and the soil should be disinfected locally to kill poisonous nematodes.

The grape housekeeper replied.