What causes little leaf disease?

Little leaf disease in fruit trees has occurred frequently in recent years, and there is a trend of it worsening year by year. Little leaf disease not only causes stunted plants and slow growth and development of branches and buds, but in severe cases it can also lead to the death of branches and leaves, preventing fruit trees from flowering normally, or producing small or deformed fruit. So what causes little leaf disease?

Little leaf disease in plants is a symptom of zinc deficiency. In addition, there is another important factor, which is improper pruning of fruit trees.

Excessive phosphate fertilizer induces zinc deficiency in the soil. Among the various nutrient elements that fruit trees need, such as nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, iron, zinc, copper, manganese, selenium, molybdenum and silicon, there can sometimes be mutual synergistic effects, mutual antagonistic effects, or one-way antagonistic effects. For example, potassium has mutual antagonistic effects with nitrogen, calcium and magnesium, while nitrogen, calcium and magnesium have mutual synergistic effects (an increase in one element will favor the absorption of the other two elements); phosphorus has one-way antagonistic effects with nitrogen, zinc, potassium, magnesium, calcium, copper and silicon. When phosphorus in the soil is excessive, if nitrogen, zinc, potassium, magnesium, calcium, copper and silicon are not increased, the tree will reduce its absorption of nitrogen, zinc, potassium, magnesium, calcium, copper and silicon, and show symptoms of deficiency of nitrogen, zinc, potassium, magnesium, calcium, copper and silicon. In production, zinc deficiency in many orchards is related to applying too much phosphate fertilizer.

After excessive application of calcium phosphate, zinc in the soil reacts with the excessive phosphorus to form zinc phosphate precipitate, which affects the absorption of zinc and causes obvious symptoms of zinc deficiency; after excessive application of alkaline phosphate fertilizers such as calcium magnesium phosphate, soil alkalinization and reduced availability of zinc will both affect the absorption of zinc.