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Physiological leaf roll in potatoes
[Disease diagnosis] The symptoms of physiological leaf roll and viral leaf roll share certain similarities. The main manifestation is the upward curling of the leaflets. Usually the lower leaves of the plant, or all the leaves of the whole plant, become brittle and curl upward into a tube shape. In some cases only the leaf margins curl slightly upward; in others the curling is severe, forming a spoon shape or tube shape. In severe cases, the leaves become thicker, brittle and hard, and darker and more intense in color, giving a feeling of a messy, clustered clump. The characteristic of physiological leaf roll is that the leaf rolling shown by affected plants is relatively uniform. [Cause] There are several causes of physiological leaf roll: for example, excessive one-sided application of nitrogen fertilizer,
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Green copper emulsion is highly effective against rice bacterial leaf streak
In an average epidemic year, the control efficacy reaches 85-91%, which is 10-15 percentage points higher than that of Japanese-made chlorothalonil. Method of use: in an average epidemic year, spraying twice is sufficient. The first spray is applied at stages 2-4 of young panicle differentiation in rice; 7 days after treatment the disease tends to stabilize, new acute lesions decrease significantly, and the original lesions stop developing after turning yellow. The second spray is applied 10 days later, using 100 mL of 12% green copper emulsion per mu each time, diluted 500-600 times for spraying. After 20 days, the rice leaf color turns noticeably greener, and the newly emerged flag leaf and the second leaf from the top have no
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Is copper hydroxide effective for treating rice bacterial leaf streak?
How effective is copper hydroxide for treating rice bacterial leaf streak? How many applications are needed? Please answer objectively. Thank you for your question. The answer is as follows: Copper hydroxide can control rice bacterial leaf streak, bacterial leaf blight, rice blast, sheath blight and rice false smut, etc. Before or at the early stage of disease onset, spray with a 53.8% dry suspension concentrate at 900-1100 times dilution, with 2 consecutive applications.
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Occurrence and Control of Panax notoginseng Leaf Rot
Symptoms This disease can harm all aboveground organs except the roots. The most typical symptom is the formation of black spindle-shaped lesions at the top of the petiole. When temperatures are high, the lesions rapidly encircle the petiole and quickly spread to the base of the leaflets, forming light black water-soaked lesions on the leaves with irregular edges. The diseased part of the petiole quickly softens, causing the upper leaflets to droop (commonly known as "twisted-down plate"). On the diseased areas, pale yellow powdery masses tinged with pink are often visible, which are the fruiting bodies of the pathogen. When attacking the middle of the leaf blade, it forms black irregular lesions with irregular edges,
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Symptoms of Schisandra Leaf Blight and Its Prevention and Control Methods
Schisandra leaf blight is a common disease, widely distributed in Liaoning, Jilin, Heilongjiang and other provinces, and can cause serious consequences such as early defoliation, fruit drop, death of new shoots, weakened tree vigor, decreased fruit quality, and reduced yield. 1. Disease symptoms Leaf blight mainly damages leaves. According to the different initial sites on the leaves and the size of the lesions, it can be divided into two types. ① The disease first starts from the leaf tip or edge, then spreads to the leaf margins on both sides, and then extends toward the center, gradually forming large brown patches; as the disease further
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What is leaf curl disease in geranium viral diseases
There are many types of geranium viral diseases. The following common ones are mainly distributed in Europe and the Americas, with a few reports also in Asia. Geranium leaf curl disease is also known as geranium crinkle leaf disease. [Pathogen] Pelargonium leaf curl virus (Pelargoniumleafcurlvirus, PLCV), thermal death point 85-90°C. [Symptoms] Chlorotic spots appear on young leaves, then develop into yellow round or star-shaped spots with a dark yellow center and a pale halo around them, along with necrotic perforation
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Symptoms and Control Methods of Common Leaf Spot Diseases in Geraniums
Geranium leaf spot disease is a common disease in spring and summer. It is most likely to occur in hot and rainy seasons, often causing most of the infected leaves to die and drop off. When the stem is infected, it turns black, wilts and rots; cutting open the base reveals brown or black vascular bundles. Affected cuttings fail to root, with rot starting from the stem and developing upward, causing leaves to wilt and die. Symptoms: Geranium leaf spot disease includes two types: black spot disease and brown spot disease. Black spot disease: initial water-soaked spots appear on leaves, semicircular to irregular in shape, later becoming circular, 2 to 3 mm in diameter,
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Causes and Control Methods of Pelargonium Leaf Curl Disease
Pelargonium leaf curl disease, also known as Pelargonium crinkle disease, is a viral disease that has only been found in the Shanghai area. Symptoms: The leaves of infected plants curl downward and become stunted. In severe cases, the plants die. Pathogen: The pathogen is Pelargonium leaf curl virus (PLCV). Disease pattern: The virus is transmitted by sap, grafting and soil; no vector insect has been found. In summer and autumn, the symptoms of the disease are not obvious, and the residual virus-carrying plant debris from pruning can spread the virus.
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Identification and Control Methods for Geranium Alternaria Leaf Spot
Geranium Alternaria leaf spot is a common leaf disease of geranium. The pathogen has a wide host range and can attack many woody and herbaceous ornamental flowers, seriously affecting their ornamental value. Symptoms: In the early stage of the disease, chlorotic spots appear on infected leaves, and the lesions gradually expand to form larger circular spots. The spots are dark brown with concentric rings. In the late stage of the disease, a dark green mold layer appears on the spots, which consists of the conidia of the pathogen. Pathogen: The pathogen is Alternaria tenuis Nees, belonging to
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How to prevent and control bacterial leaf spot in geraniums?
Geranium, also known as zonal geranium, fish geranium, and horseshoe geranium. It is native to South Africa. It prefers cool conditions, fears high temperatures, and is not cold-tolerant. It requires ample sunlight. It is not tolerant of waterlogging but is slightly tolerant of drought, and prefers fertile loam with good drainage. In spring and autumn, when the weather is cool, it is most suitable for the growth of geraniums. In winter, indoors at around 15°C during the day and no lower than 5°C at night, with sufficient light, they can bloom continuously. In hot summers, the plants enter a dormant or semi-dormant state, and should be placed in partial shade with attention to controlling watering. It is resistant to chlorine. Pelargonium plants
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