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What are the prevention and control methods for fish diseases and enemies?
1. Blue-green algae disease: Blue-green algae include Microcystis aeruginosa and Microcystis flos-aquae. They generally occur in summer and early autumn, and they like to grow in water with higher temperatures and relatively strong alkalinity. When the pH is 8-9.5 and the water temperature is 28°C-32°C, they reproduce fastest. If there are more than 500,000 colonies per liter of water, the dissolved oxygen in the water is often insufficient for their needs, and they will die in large numbers on their own. After the algal bodies die, proteins decompose easily, producing toxic substances such as hydroxylamine and hydrogen sulfide. When these toxins accumulate in the water, they can not only poison fish to death, but even cattle and sheep that drink this
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Symptoms and Control Methods of Potato Wart Disease
[Pathogen scientific name] Synchytrium endobioticum (Schilb.) Percival [Host crops] Potato, tomato, black nightshade, etc. [Disease diagnosis] It mainly damages the underground parts of the plant, occurring commonly on tubers and stolons. On the eyes of infected tubers and on stolons, because the pathogen stimulates continuous cell division, tumors of varying size, irregular shape and rough, protruding surface form, resembling cauliflower. The surface of affected tubers often cracks. The wart tissue is yellow-white in the early stage, the part exposed above the soil surface turns green, and later turns dark brown. The tissue is soft, prone to rotting and produces a foul odor, with brown slimy matter. During storage, diseased tubers can still develop, even causing the whole storage cellar to rot. Diseased tubers turn black and give off a foul odor; after prolonged boiling they do not soften easily and are difficult to eat. When the aboveground parts are affected, the appearance does not differ noticeably from healthy plants, but in the later stage diseased plants are taller than healthy ones, remain green longer than healthy plants, have more branches and bear more berries. On severely diseased plants, stems, leaves and flowers can all be affected, forming wart lesions or deformities. The causal agent is the endobiotic chytrid fungus. The pathogen is endoparasitic and does not produce hyphae; the vegetative thallus is initially a naked, wall-less protoplast (amoeboid body), and later becomes a walled unicellular thallus. In the reproductive growth stage, the unicellular thallus transforms into a resting sporangium sorus. The sporangium sorus is nearly spherical and contains 4 to 9 sporangia. The sporangia are spherical, rust-brown, and on germination produce zoospores. The zoospores have a single flagellum and are spherical to pear-shaped. Some zoospores mate to form zygotes. The zygote resembles a zoospore and has two flagella; both can infect the host.
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Identification and Control Methods of the Russian Olive Psyllid
Scientific name Trioza magnisetosa Log. Homoptera, Psyllidae. Hosts: Russian olive (Elaeagnus angustifolia), jujube. Damage characteristics: adults and nymphs pierce and suck the sap of young buds, tender twigs and leaves; infested young buds often die, infested leaves mostly curl toward the underside, and in severe cases the twigs and shoot tips die, weakening the tree's vigor, with heavy flower and fruit drop. Morphological characteristics: adult body length 2.5-3.4 mm, dark green to yellowish brown. Compound eyes large, protruding, reddish brown. Antennae filiform, 10 segments, the terminal 2 segments black
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Recent Rice Pest and Disease Occurrence and Control Methods
Since entering July, our city has experienced continuous rain followed by high temperatures after the rain, which is extremely favorable for the occurrence of rice pests and diseases in the later stage. Currently, most of the rice in our city has entered the booting to heading stage, which is precisely the susceptible period for rice pests and diseases. On August 7, our station conducted field surveys in Tangdian, Datun and other areas, and found occurrences of rice blast, sheath blight, and rice leaf roller, requiring urgent control. The specific situation is as follows: Rice blast: Leaf blast was found on Yunhui 290 planted in Xinwafang, Datun, with a diseased leaf rate of 3.6%, disease index of 0.75, and an area of 2 mu. Sheath blight
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Symptoms, Identification, and Control Methods of Root Rot in Dianthus
Identification points: Dianthus root rot mainly affects the root system. After the plant is infected, its growth becomes weak, there are very few fibrous roots on the diseased plant, and the leaves wilt. In severe cases, the root system turns entirely brown, rots, and the root cortex peels off easily, and the whole plant withers. Occurrence characteristics: The pathogen belongs to the Pythium group. This fungus survives on plant residues in the soil and is an important soil-borne fungus that can harm many kinds of plants, causing Pythium root rot. The disease is severe when the soil or growing medium is slightly alkaline and humidity is high. Under conditions such as being placed too densely, excessive watering, and poor ventilation, it is also prone to
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What are the control methods for Dianthus leaf spot?
Identification points: Dianthus leaf spot mainly affects the leaves. Leaf spots are initially yellow, gradually becoming dark brown round to oval spots, and later the spots turn grayish brown with dark brown edges; in severe cases the spots join together, causing the leaves to turn yellow, wither and drop early. Under humid conditions, many small black granules appear beneath the spots, namely the conidia and conidiophores of the pathogen. Occurrence characteristics: a fungal disease. It can occur year-round in greenhouses. Under conditions such as abundant rain, heavy fog and heavy dew, the disease occurs easily. Poor ventilation and light transmission, extensive management and weak plant growth can all
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What are the control methods for Fusarium wilt of carnation?
1. Symptoms: The infected parts turn yellowish-brown or brown with dry rot, spreading rapidly upward; the stem shrinks, and a cross-section of the xylem shows yellowish-brown or purplish-brown decay. The leaves on the aboveground part of the diseased plant lose their luster and become soft, and the leaves near the root crown first turn yellow and droop. The disease develops rapidly, and the plant quickly wilts; if the pathogen invades from one side of the plant, only half the plant wilts first. When the environment is humid, colored filamentous structures can be seen at the rotted root crown area; these are the fruiting bodies of the pathogen. 2. Pathogen: Fusarium dianth
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Symptom Identification and Control Methods of Carnation Rust
Rust is one of the common diseases of carnation, and susceptibility varies among cultivars. It generally occurs commonly in autumn and winter when control is neglected, and is severe in continuous cropping fields where the previous crop was heavily diseased. The whole plant can be affected, with leaves suffering the most severe damage. Reddish-brown spots appear on both the upper and lower surfaces of diseased leaves, and the epidermis around the diseased area ruptures, exposing red powdery material, which is the uredinium of the pathogen. In the later stage, the color of the diseased area deepens, and after the epidermis ruptures, dark brown to black powdery material appears, which is the telium of the pathogen. Rust can also damage the stems and sepals of carnation. Carnation rust is caused by the fungus Uromyces dianthi, and is a
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Pests and Control Methods for Cut-Flower Carnations
(1) Red spider mite: damage is severe under high temperatures above 25°C (July to August), with a small number of occurrences around mid-April. Control methods: remove dead branches, fallen leaves and weeds, improve cultivation conditions, and appropriately increase air humidity. At the initial stage of occurrence: spray 40% dicofol emulsifiable concentrate at 1000-1500 times dilution, or 40% dimethoate emulsifiable concentrate at 1500 times dilution, or 25% phosmet emulsifiable concentrate at 1000 times dilution, or fenvalerate at 800-1000 times dilution, or saomantjing, propargite, hexythiazox, pyridazinone, flufenoxuron, miechongling, etc.
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Control Methods for Rhizoctonia Stem Rot of Carnation
It mainly attacks the root crown area of the plant, and infected plants dry up and die quickly. The pathogen infects the root crown of seedlings near the soil surface, initially causing brown or dark brown spots that gradually spread to the surrounding area. The base of the seedling rots and constricts, causing lodging. When older seedlings at the stem base are affected, the cortex near the soil surface rots and becomes slimy. The leaves of diseased plants turn pale white, wilt and droop, and finally the whole plant dies. Control methods: (1) Before cuttings are taken, flower pots and soil must be disinfected. (2) Plants should be grown on raised beds, and watering should be controlled so that the potting soil does not become too wet. (3) Disinfection
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