Citrus yellowing has become a phenomenon that the majority of orange farmers generally need to face, citrus yellowing will cause the leaves to lose green and yellow, photosynthetic ability is greatly weakened, the tree potential will cause a series of problems after the deterioration, the final result is low yield, poor quality, so that the income of fruit farmers suffers direct losses. So today we will talk about the phenomenon and causes of citrus yellowing? Citrus Yellowing Improvement Technology Essentials!
First, improper cultivation management caused by yellowing phenomenon:
1. Mechanical damage: if the circumcision is too deep, it hurts the xylem, which hinders the nutrient transport and causes yellowing. Circumcision is severe, too much fruit is hung, resulting in dead trees.
2. Unreasonable use of herbicides: such as drifting when spraying glyphosate, causing yellowing and defoliation of citrus, and young leaves do not turn green and curl leaves. At the same time, the phosphate root of glyphosate degradation product is easy to combine with iron and zinc in the soil, so that citrus has a deficiency of small leaves, flowers and leaves, and bushes.
3, unreasonable fruit hanging: some fruit farmers are in a hurry to make quick profits, do not follow the growth law of nature, and hope to enter the harvest period of fruit trees in advance through fertilization and other methods, resulting in excessive consumption of fertilizer efficiency of fruit trees, so that the nutrition of fruit trees is seriously overdrawn and overloaded with fruits, and the early entry into the aging period leads to yellow leaves.
4, the use of inferior organic fertilizer: such as the use of uncorrozen organic fertilizer, the production of secondary fermentation, the production of high temperature and toxic substances, resulting in the phenomenon of burning root yellowing.
5. Improper fertilization and use of fertilizer produce fertilizer damage: such as too much fertilization at one time or near the trunk, the bark of the trunk is burned; some use chlorine-based compound fertilizer, resulting in root yellowing.
6. Improper use of pesticides causes drug harm: such as improper use of paracycline causes drug harm; the use of inferior mineral oil yellowing; improper use of emulsion at high temperatures causes leaf burning.
7, high temperature and drought: such as high temperature and drought weather, prone to sunburn, sun fruit; seriously caused by a large number of fruit fallen leaves. 8, stain damage: such as flood disasters, flood soaking for 48 hours, seriously causing dead trees; orchards with high groundwater level, poor drainage, easy to appear roots, tree body yellowing.
2. Insect pests
1. Grasshopper: Grasshoppers belong to the genus Grasshoppers of the hemiptera Cicada family, the larvae eat the root juice and harm the roots; the adults suck the sap of the young branches to cause the green turn slowly; the spawning goes deep into the xylem, resulting in the phenomenon of dead branches.
2, Tianniu: Tianniu Coleoptera Tianniu family, adult insects bite the skin layer of young branches, forming dead shoots; larvae moths eat trunks, main roots, there are worm channels in the xylem, insect dung is discharged outside the worm road, and there are piles of insect dung (white foamy gelatin) under the trunk.
3, popcornworm: popcorn worm belongs to the Coleoptera Gidinaceae family, mainly for the phloem and xylem of the trunk bark, adult insects eat citrus young leaves into small gaps, larvae in the trunk and the main branch of the cortex moth, the formation of many meandering insect path, the phloem is destroyed, so that nutrients can not be transported normally, the leaves fall off, the branches wither, the tree is weak or the whole plant dies.
3. Diseases
1. Huanglong disease: Huanglong disease belongs to the phloembacter bacteria, and the leaves have three types of yellowing: mottled yellowing, uniform yellowing and hypotinous yellowing. It is mainly transmitted through psyllids, seedlings and grafts.
2. Split skin disease and foot rot disease: Split skin disease is a viral disease (red orange, fragrant orange as rootstock has good resistance, and citrus rootstock is susceptible to infection). Foot rot is a fungal disease of Phytophthycete, which is an earth-borne disease with rotten bark and a lees smell. The lateral veins of the midrib of the leaf are yellowed.
3. Flow glue: Flow glue is divided into two types: physiological and pathological flow glue. Physiological streaming gum mainly occurs on the main trunk and main branches, and the incidence is heavy in the rainy season. Pathological fluid gum is a fungal disease of ascomycetes, which mainly harms the branches, and does not flow gum in that year, with the characteristics of latent infection. It can be divided into dry type flow glue and wet type flow glue.
4, root-knot nematodes: root-knot nematode disease is a microorganism that harms the root stem of citrus, which will form nodules of varying sizes on the root tips of citrus, nodules spindle-shaped or irregular shaped, nearly sesame seeds to mung bean grains large, initially milky white, and then turn yellow-brown to black-brown, sparse root hairs, citrus leaves yellowing, partially curly leaves.
Fourth, deficiency of hormones
Key points of citrus non-physiological yellowing improvement technology:
1. The tree body is whitewashed;
2. Reasonable pruning;
3. Improve the soil environment;
4. Do a good job of antifreeze measures for the tree body in winter.
Citrus physiological yellowing improvement technology points: 1, buried fertilizer; 2, irrigation; 3, leaf spraying.
Step 1: Apply sufficient base fertilizer, balanced nutrition (to solve the problem of soil and nutrients), it is recommended to use high calcium bio-organic fertilizer + black tiger compound microbial fertilizer, trenching and burial. It can meet the nutrient needs of the early stage of crops, comprehensive and balanced nutrition, and robust crop growth; increase soil organic matter content, enhance soil water retention and fertilizer retention capacity; add beneficial microorganisms, activate the number of beneficial microbial flora in the soil, inhibit harmful organisms, and reduce the occurrence of crop diseases.
The second step: cultivate the land to promote roots, resist heavy stubble (solve the root system, anti-heavy stubble problem), and irrigate the roots with black tiger microbial fungus mixture with water. It can promote the development of crop roots and improve crop survival rate, improve crop stress resistance and solve the problem of heavy stubble, reduce the activity of heavy metals in the soil, and reduce the absorption of toxic and harmful substances such as heavy metals by crops.
Step 3: Activate secondary metabolism, promote photosynthesis (solve the problem of leaf and photosynthesis), and spray foliar with Concentrated Tiger to promote photosynthesis with Chinese herbal nutrient solution. It can improve the photosynthesis of citrus leaves and increase citrus yield, correct the phenomenon of citrus yellowing, alleviate the medicinal harm produced by herbicides, and improve the ability of citrus to resist drought, cold and flood.
Step 4: Expand the fruit, improve the quality and increase the yield (solve the problem of fruit and puffed fruit), and use the organic and inorganic full water-soluble fertilizer (10-6-20) or the high potassium type large element water-soluble fertilizer (13-7-40) to wash or water. It can make the fruit expand evenly, color well and evenly; the fruit sells well, the sugar content is high, the soluble substances are increased, and the taste is pure; promote the early market of crops, extend the picking period, and increase crop yield.
The fifth step: disease suppression and insect repellent, degradation of pesticide residues (to solve the problem of quality, pesticide residue reduction), foliar spraying with Flying Tiger Chinese herbal nutrient solution, improve citrus stress resistance, inhibit the occurrence of diseases and insect pests, less or even no pesticides; reduce pesticide residues in agricultural products.
If you are interested in citrus yellowing phenomenon and the causes ? Citrus yellowing improvement technology points have any questions, or want to know more about crop fertilization programs, welcome to leave a message to discuss together!