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What to do when cotton develops red leaf blight during the boll-setting stage
Control measures for cotton red leaf blight: 1. Apply fertilizer reasonably, and skillfully apply the cotton topping fertilizer; nitrogen, phosphorus and potassium should be applied together or foliar fertilizer should be applied. 2. Strengthen field management, cultivate frequently, improve root respiration conditions, promote root development, prune and remove side branches in time, remove old leaves and control pests and diseases. 3. Spray for protection, using 70% mancozeb or 75% chlorothalonil 600-800 times solution or 70% thiophanate-methyl 800-1000 times solution plus foliar fertilizer (potassium dihydrogen phosphate, Lvzhiyuan, etc.) for spraying, once every 5-
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Occurrence Patterns and Control Methods of Cotton Red Leaf and Stem Blight
Disease symptoms and occurrence patterns: Cotton red leaf and stem blight is an explosive disease that frequently occurs in the middle and late stages of cotton growth. It can cause leaves to turn red from bottom to top until they drop off. The leaf veins remain green, the leaf mesophyll turns red, and the leaves become thicker, brittle, and wilted before finally dropping. When the stem is cut open, it does not change color, which distinguishes it from cotton Fusarium and Verticillium wilt. Generally, in old cotton-growing areas, the disease is more severe in cotton fields with continuous cropping year after year, sandy soil, too shallow a plow layer, or insufficient fertilizer lacking potassium fertilizer. Drought in the middle and late stages, along with severe potassium and zinc deficiency in the soil, can also easily accelerate the occurrence of this disease.
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What are the three main causes of cotton red leaf stem blight?
Cotton red leaf stem blight is a physiological disease caused by potassium deficiency. It occurs in the middle and late stages of cotton growth, and in dry years the occurrence and severity of damage are more serious. In the field, cotton generally begins to show symptoms at the bud stage, and the disease is most severe during the boll-setting and boll-opening stages. Symptoms mainly appear on the leaves. Diseased leaves develop from top to bottom and from the outside inward. Diseased leaves begin to lose green color from the edges, first turning yellow, then producing red spots, and finally the whole leaf turns red, the mesophyll thickens, wrinkles and becomes brittle, while the veins remain green. In severe cases, the leaves of the whole plant lose green color, then turn red and brown, the leaves scorch and fall off, leaving bare stems, and the plant
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How to prevent cotton red leaf stem blight? These integrated measures must be mastered
Cotton red leaf stem blight is a physiological disease. In recent years, it has occurred in large amounts in the cotton region of the Yangtze River Basin in our area. It begins at the early flowering stage, and is more severe and widespread from the full flowering stage to the boll-setting stage. In our area specifically, it occurs sporadically in July and August. It reaches its peak from mid-to-late September to October. Lightly affected plants are yellow and thin, with few and small bolls, short fiber, and poor boll opening; severely affected plants die prematurely, and the bolls cannot mature, greatly affecting yield. 1. Disease symptoms. At the early stage of the disease, red and purple spots appear on the leaves, gradually spreading until the whole leaf turns red
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How to prevent and control cotton red leaf stem blight? A full analysis of control measures
I. Symptom identification After the plant is affected, the leaves turn dark green and become thick and brittle, then small red dots are scattered on the leaves, and finally the whole leaf turns red while the veins remain green, which is red leaf stem blight. When the disease is severe, the base of the petiole becomes soft, loses water and shrinks, causing the leaves to wither and fall off, and the top of the stem becomes scorched and dry. At the same time, it easily triggers repeated infection by target spot and brown spot, causing the diseased plant to scorch and die. Some plants can still grow adventitious buds after the diseased leaves fall off. Plants with severe and early onset are short, with poor root development, and both the main root and lateral roots are
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Symptoms and Control Methods of Leaf Blight in Hybrid Magnolia
The main symptoms occur on the leaves, and in severe cases can spread to the petioles and flower buds. The lesions mostly occur at the leaf margins. In the early stage, they are chlorotic yellow spots, water-soaked in appearance. Numerous lesions merge into patches, expanding outward in a fan shape, with dark brown edges and grayish-yellow centers, which can cause early defoliation. In humid environments, black-gray granular bodies appear on the fallen leaves. Causes of the disease: This disease is a fungal disease; the pathogen survives in leaf buds and on diseased plant residues, spreads via air currents, and can directly infect and damage through the stomata of leaves that are weak in growth or physiologically injured. Injured plants and environmental conditions with high wind speed
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Symptom Identification and Control Methods of Garlic Leaf Blight
Leaf blight is a major disease of green garlic and, in severe cases, causes the entire leaf to die off, affecting yield. I. Symptom identification This disease mainly damages leaves and flower stalks. When leaves are infected, it usually starts from the leaf tip and gradually develops toward the leaf base, spreading from the bottom upward. At first, pale white small round spots appear, which later expand into oval or irregular grayish-white or grayish-brown lesions, and black mold-like growth develops on the diseased parts; in severe cases, the entire leaf dies off. When flower stalks are infected, they tend to break at the diseased part, and finally many small black grains are scattered on the lesions.
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Grasp the prevention and control of scallion blight in summer
In the hot, humid and rainy seasons of spring and summer, epidemic scallion blight is prone to breaking out, causing scallion leaves to droop and wilt, or even rot, resulting in serious losses, so related prevention and control work must be done well. In the hot, humid and rainy seasons of summer, epidemic scallion blight is prone to breaking out, which can turn originally green scallions covered with yellow spots within a few days, then turning white, with leaves drooping and wilting, or even rotting, causing serious losses. Scallion blight mainly damages scallion leaves and flower stalks. In the early stage of infection, scallion leaves show indistinct pale greenish-white lesions, which after expansion become grayish-white spots, spreading along
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Symptoms and Control Methods of Cotton Leaf Blight
Symptoms Also known as cotton Cercospora leaf spot. It mainly damages leaves. Infection usually occurs in the late growth stage of cotton. At first, many dark red small spots appear on the leaves, then expand into nearly round lesions with purplish red, slightly raised edges and brown centers. Under moist conditions, a white mold layer forms, which is the pathogen's conidiophores and conidia. Affected leaves break very easily. Pathogen Mycosphaerella gossypina (Cooke) Earle, called cotton ball fungus, belongs to the Ascomycota fungi. The ascocarp is spherical and black, and the ascospores
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What are the control methods for southern blight in orchids?
Southern blight is caused by the fungus Selerotiumrolfsii, which harms the stem base and roots from seedlings to mature plants, and Cymbidium hybridum is more susceptible to this disease. When the disease occurs, white mycelium can be seen at the stem base, the stem base turns brown, the roots dry up, and a large number of small brown sclerotia form, causing the plant's stem base to soften and die. This pathogen has a very wide host range and causes more serious damage to bulbous flowers and perennial flowers. It also has strong saprophytic ability and can survive for a long time in the substrate or old pots through sclerotia. This fungus can also infect Phalaenopsis
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