symptom
Zinc deficiency in grapes often shows two symptoms. One is that the leaves of new shoots become smaller, which is often called "small leaf disease". The base of the blade has a large opening angle, the edge of the blade is sawtoothed and sharpened, and the blade is asymmetrical. The second is the emergence of mosaic leaves, chlorosis and yellowing between the veins, clear veins, and narrow green edges.
Lesions with severe discoloration are finally necrotic. When some grape varieties are deficient in zinc, it is easy to cause less seed formation, smaller fruit grains, irregular fruit sizes, and reduced yield.
Etiology
Zinc deficiency in grapes often begins to occur in early summer, and the front ends of the main and auxiliary shoots are the first to suffer. In alkaline soil, zinc salts are often easily transformed into insoluble state, difficult to be absorbed by grapes, often causing zinc deficiency. The zinc content in the soil is low or the sandy soil is washed away by rainwater, which can easily cause zinc deficiency in grapes.
Prevention method
(1) Strengthen soil management. In sandy land and saline-alkali land, compost made by enzyme bacteria or decomposed organic fertilizer should be added.
(2) Spray zinc on the leaves. Spray 500-1000 times zinc sulfate solution on the grape plants where zinc deficiency occurs.
(3) Apply zinc salt to the notch. When the grapes are deficient in zinc, applying zinc sulfate to the cut can restore the diseased tree to normal and increase the yield. The effect of zinc sulfate application in soil was not obvious.
