Prevention and control of yellowing disease of peach trees

First, reasons

1. The main reasons for iron deficiency of peach trees in iron deficiency protected areas are as follows:

The planting density of ① is high, some even reach 1m × 0.8m, the nutrient area of each tree is small, the roots and roots cross each other, and the iron ions released from the soil can not meet the absorption of the roots.

After the fruit of ② peach tree, the load is large, the organic nutrition is preferred to supply the fruit growth, the root growth is inhibited, the ability of the root to secrete acid substance is weakened, and the iron ion in the soil can not be effectively absorbed by the root.

③ is affected by soil pH. Iron ions in neutral and alkaline soils are easily fixed by hydroxide ions to form insoluble iron hydroxide, which can not be absorbed by peach roots and occur iron deficiency symptoms, and mainly occur in new leaves.

two。 After fruit harvest, pruning overweight fruit before harvest, a variety of organic and inorganic nutrients were mainly used to supply fruit growth, and root growth was inhibited. After fruit harvest, the root system is in urgent need of leaf supply of organic nutrition, at this time, heavy retraction pruning is carried out, and a large number of vegetative branches and leaves are lost, resulting in insufficient nutrition supply of underground root growth and death of capillary root due to overpruning. Root system can not absorb nutrients well, resulting in insufficient supply of aboveground nutrients.

3. The long-term application of a large number of chemical fertilizers with more chemical fertilizers and less organic fertilizers results in soil consolidation, poor physical and chemical properties, barren soil, poor structure, low organic content, and the decrease of soil active bacteria, affecting the decomposition and release of soil nutrients. Soil viscous weight and permeability are poor, which affect the growth of root system.

4. Root disease peach root disease is another important cause of peach leaf yellowing. Plants suffer from root cancer disease, purple feather disease, root rot disease and so on, which affect root growth, hinder root absorption of nutrients and water, and cause tree potential weakness. when it's serious, the plant dies.

II. Prevention and treatment

1. Control of ① sparse planting by iron deficiency: the planting density is 2.5m × 1m ~ 3m × 1m, which increases the soil range of root absorption of nutrients and water, makes the iron ion in the soil meet the absorption of root system, and creates a good growth environment for plant growth. ② reasonable load: determine the yield according to the situation of peach trees, generally, the yield per mu is not more than 3000 kg, and then decompose the yield per mu into each tree, the calculation formula of fruit amount per tree is: fruit amount (number of fruits) ≈ plant yield (kg) / single fruit weight (kg). ③ spraying foliar fertilizer: spraying 0.1% ferrous sulfate plus 500x rice vinegar solution to the leaf. ④ infusion control: when there is iron deficiency in individual shoots on the plant, hang it on the tree with a mixture of 0.1% ferrous sulfate and 0.5% acetic acid, and insert the iron deficient shoots directly into the bottle. The mixture can also be packed in an infusion bottle, hung upside down on the branch, punched a hole in the trunk, and infused with a medical infusion device.

two。 After light pruning, fruit-bearing branches are pruned, mainly thinning, thinning upper dorsal branches, erect branches, thin and weak branches, disease and insect branches, cross branches, combined with artificial coring, twisting, taking branches, etc., to retain certain vegetative branches to balance the tree potential.

3. Rational fertilization, increase the application of high-quality organic fertilizer, control the soil viscous weight of chemical fertilizer, increase the application of high-quality organic fertilizer in autumn, improve soil permeability and improve soil physical and chemical properties. If the soil is sticky and heavy, filling some river sand in the planting pit will have a certain effect.

4. Control root diseases to check whether the seedlings have diseases, soak the roots with 1% copper sulfate solution or 2% lime water for 1 minute, or soak the roots with Kmur84 (cancer Kangning) for 5 minutes, and then colonize. If root cancer plants are found, the root nodules are removed with a sharp knife and sterilized with 1% copper sulfate 100 times solution.