What are the control methods for iron deficiency chlorosis in jujube trees?
Distribution and harm: Yellow leaf disease occurs in many jujube-growing areas, among which iron deficiency chlorosis is relatively common and is a physiological disease. It can cause tree decline, affect jujube yield, and in severe cases can cause tree death.
1. Symptoms: Mild iron deficiency chlorosis can turn part of the jujube tree's leaves yellow, but the leaf veins remain green; this is the most obvious feature of iron deficiency chlorosis. In severe cases, all jujube leaves turn yellow and may even become albino. Diseased trees produce few flowers, are difficult to set fruit, have underdeveloped branches, gradually decline, and may even die. The disease is relatively likely to occur when jujube trees sprout branches and unfold leaves, and it is severe from May to June.
2. Pathogen: The disease is caused by a lack of absorbable iron in the soil. Iron ions are an important substance for chlorophyll formation. A lack of absorbable iron in the soil blocks chlorophyll formation and causes yellow leaf disease. Iron deficiency chlorosis occurs more often especially on saline-alkali land.
3. Occurrence pattern: In alkaline soil, yellow leaf disease is very likely to occur when the pH value exceeds 8. Because of the iron stored in the tree body and the small amount of absorbable iron in the soil, the leaves are still green when they first unfold. During the rapid new shoot growth period and leaf unfolding period, the iron required for growth and development increases, while the soil supply is insufficient, resulting in iron deficiency chlorosis; the leaves at the tips of new shoots are especially affected.
4. Control methods
1. Strengthen management, apply more organic fertilizer, deep plow to improve the soil, and improve the soil.
2. Combined with autumn fertilization, apply 100-250 grams of ferrous sulfate according to tree size.
3. During the period when jujube trees sprout branches and unfold leaves, use foliar spraying to supplement iron. Spray the trees with 800-1000 times diluted ferrous sulfate, once every 10 days, for 3-5 consecutive sprays.