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What are the control methods for nutrient deficiency diseases in citrus
Zinc deficiency causes mottled leaf disease. Citrus mottled leaf disease is a common disease, with the typical symptom being mottled small leaves. When new leaves begin to turn green, the main veins and lateral veins appear markedly green, while the remaining tissue is light green to yellowish white and glossy. In severe cases, only the area near the main vein or thick lateral veins is green, and the new leaves are narrow and mottled, mostly upright, with short internodes and clustered branches. Mottled disease is caused by zinc deficiency. Many soils are deficient in zinc, such as soils formed from granite, gneiss, and serpentinite, which contain little zinc; acidic sandy soils lose zinc easily; in alkaline soils zinc readily forms insoluble compounds, thus causing zinc deficiency. In addition, soil that is too dry or too wet, low humus content or excessive application of organic matter, which hinders contact between roots and soil, as well as heavy pruning, all make zinc deficiency likely to occur. Foliar fertilization can achieve fairly good results in controlling zinc deficiency. It is advisable to spray 0.2%-0.3% zinc sulfate solution (with an equal amount of lime) once during the tender shoot stage, and spray 2-3 times for severe zinc deficiency.</p><p></p><p>Copper deficiency or boron deficiency causes dieback disease. In the early stage of copper deficiency in citrus, new shoots are long, soft, and slightly curved, the leaves are large and dark, and fruiting is low, so it is easily mistaken for excessive vigor. In severe cases, the tips of the shoots turn tea-brown and die, short weak clustered branches appear, and they dry out and drop early and gum exudes; when the branches mature, the wounds are reddish brown, and parts of the leaves are reddish brown. Citrus has a very small copper requirement, and ordinary spraying of Bordeaux mixture is already sufficient. However, copper deficiency is likely to occur in peat soil, acidic sandy soil, soil with high organic matter content, as well as on abandoned grazing land and abandoned cemetery land; excessive application of barnyard manure and phosphate fertilizer also causes copper deficiency; newly reclaimed citrus orchards that have not been sprayed with Bordeaux mixture or other copper preparations for several years are prone to copper deficiency. Boron deficiency in citrus: the growing points of buds die continuously, forming clustered buds; leaf veins swell, become corky or split; the fruit is small and deformed, with thick hard peel, and brown resin deposits are present in the fruit center and spongy layer. Boron is easily lost from acidic soil, hence boron deficiency. In soil parent materials such as granite, gneiss, and schist, boron content is extremely low; in alkaline soil its solubility is poor, so boron is also deficient. Excessive application of phosphate fertilizer or lime, or soil drought, all affect the availability of boron and the absorption of boron by roots; sour orange has weak boron uptake, so citrus grafted onto sour orange rootstock is generally deficient in boron. For copper deficiency, Bordeaux mixture or other copper fertilizers can be sprayed. To supplement boron, soil application can be used, or 0.05%-0.1% boron fertilizer solution can be sprayed at the bud stage, flowering stage, and small fruit stage.</p>
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Integrated Control Methods for Anthracnose in Citrus Cultivation
After damage, it causes leaf spots, fruit drop, and branch dieback, weakening tree vigor and even killing the entire tree, greatly affecting citrus yield and tree vigor. In particular, the rainy and sunless conditions last autumn caused severe waterlogging in some citrus orchards, poor root growth, and weak tree vigor, which allowed the anthracnose pathogen
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Key Points of Summer Citrus Pest and Disease Control Techniques
Summer's high temperature and high humidity make it the season with the highest incidence of citrus pests and diseases in the entire year. If pest and disease control is inadequate during this period, it will seriously affect the cultivation of young citrus branches and shoots, affect the development of young fruit on bearing trees, and even trigger massive fruit drop. Therefore, it is essential to effectively strengthen summer
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Detailed Explanation of Key Points for Autumn Pest and Disease Control in Citrus
Autumn is the period when citrus sends out autumn shoots, and also the period of fruit enlargement. Autumn shoots are the fruiting mother branches for bearing trees in the coming year. The quality and quantity of autumn shoots directly affect the yield and quality of the coming year. Therefore, while doing a good job in citrus fertilizer and water management, pest and disease
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Control Methods for the Mango Leaf Gall Midge Pest
This insect is distributed in production areas including Guangdong, Guangxi, Hainan, Yunnan and Fujian, and is a frequently occurring major pest. It severely damages flush-stage leaves; each leaf may have several or a dozen galls, greatly affecting the quality of new flushes. Damaged leaves are left with numerous perforations, affecting
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Control methods for the mango shoot borer (Chlumetia transversa) pest and disease
(1) Damage Also called the shoot borer. It occurs commonly in mango-producing areas and is an important pest of mango. The larvae bore into and feed on young shoots and flower spikes; infested young shoots or flower spikes wither or grow weakly. (2) Morphological characteristics Adult body length 11mm, wingspan 23mm. The dorsal side of the body is dark brown, the ventral side grayish white
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Methods for controlling thrips pests and diseases in mango cultivation
Classification: Thysanoptera, family Thripidae. I. Tea yellow thrips Scirtothrips dorsalis Hood 1. Damage: Adults and nymphs damage mango leaves, causing them to appear scalded by hot water and eventually wilt; they damage fruit, causing brown rough spots on the surface. This insect also damages tea plants, bananas
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Control Methods for Mango Fruit-piercing Moth Pests and Diseases
I. Damage. The more serious pests include the fruit-piercing moth (Oraesia emarginata), the bird-beak fruit-piercing moth, the dead-leaf fruit-piercing moth, and the super-bridge fruit-piercing moth. The adult moths use their sharp mouthparts to pierce into the fruit and suck the juice of the flesh, causing the fruit to drop. Fruit pierced before harvest will rot during storage and transport. II. Morphological characteristics.
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Mango Pests and Diseases: Control Methods for the Oriental Fruit Fly
(1) Damage Also known as the oriental fruit fly, mango fruit fly, fruit maggot, yellow fly, etc. Adults lay eggs inside the skin of nearly ripe fruit; after hatching, the larvae feed on the flesh, causing fruit splitting, rotting and dropping. The surface of infested fruit remains intact, but on close inspection there are pin holes; when pressed by hand, juice oozes out, and when cut open
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Control Methods for Scab Disease in Mango Cultivation
1. Symptom characteristics: It mainly damages the fruit, and young new shoots and leaves can also be affected. All affected parts show rough, slightly raised scab spots that are lignified. Small dark brown, slightly raised, lignified spots first appear on the fruit surface; later the lesions become densely packed and merge into patches, with a rough surface and a sunken center.
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