Vegetable virus disease needs serious prevention and control

Recently, virus diseases in vegetable crops, such as squash, spicy (sweet) pepper, bitter gourd, and oil bean, have been rapidly occurring in the greenhouses in Shandong Province, and there has been a tendency to become heavier. As we all know, in the world, vegetable virus disease has no cure so far, but can only prevent and control its harm. The problems related to vegetable virus diseases are listed for reference by farmers.

First, the principle of virus infection 1. Intrusion. Some viruses require specific insect-sucking mouthparts to implant viruses into parenchyma cells or phloem; some viruses invade plants by creating micro-wounds mechanically on the host cell wall. 2. Copy or multiply. Plant virions are different from fungi and bacteria in that they take nutrients from the cells and proliferate, but host cells change their metabolic pathways under the influence of viruses, causing normal physiological effects to be disturbed or destroyed, and the nucleic acids and proteins of viruses are synthesized. And copy and then combine with each other to form a new complete virus. 3. Operation. There are two ways to run the virus: one is between cells and cells, and the other is the speed at which the phloem enters the phloem with the flow of nutrients.

Second, the virus infection methods There are three main ways of transmission of vegetable viruses: 1. Mechanical infection or friction infection. Diseased leaves and healthy leaves rub against each other, or in agricultural operations such as transplanting seedlings, pruning, smashing, and picking up the hearts, the infected person rubs the healthy leaves with the diseased plant sap, and the virus can be transmitted to healthy plants. Such as mosaic type and ring spot virus. 2. Grafting infection. Almost all viruses, as long as the host plants can be grafted in a certain way, including cutting, bud grafting, skin grafting, etc., can occur grafting infection, the virus transmitted from the infected party to the non-toxic one. 3. Mediator infection. The mediator mainly refers to the transmission of insects, in addition to a small number of ticks, nematodes, fungi, and reeds. There are more than 400 known insect-infecting insects, the vast majority of which are sucking mouthpart insects. The chewing mouthparts of insects can also transmit viruses, such as locusts, planthoppers, whiteflies, leafhoppers, thrips, and shellfish. Worms are the most common. Such as mosaic and ring spot virus, yellowing virus and so on.

Third, the type of symptoms of viral disease Vegetables infected with the virus, sooner or later will show lesions and symptoms in the whole plant, which is an important feature of this type of disease. Virus symptom types are: 1. Color change. Such as the mosaic (leaf mosaic density and yellow mosaic), yellow (all yellow leaves evenly from the tip of the leaf to start pushing down until the whole leaf yellow or yellow-green) and so on. 2. Tissue necrosis. Such as dead spots, ring spots and so on. 3. Malformation. Mainly manifested as atrophy, lobular, small fruit, wrinkled leaves, arbor, dwarf, cluster clusters and so on. 4. Roll leaf. Such as spicy (sweet) pepper leaf virus.

The symptoms caused by a virus can be changed by the virus, host, and the environment. 1. Different strains of the same virus have different symptoms. Such as tomato mosaic virus and streak virus. 2. The same virus has different symptoms from different hosts. 3. The same virus may have different symptoms in the same host environment. Such as the tobacco mosaic virus infected tomato, high-temperature mosaic, low-temperature fern leaves or leaves. 4. Changes in environmental conditions can alter or inhibit the appearance of symptoms (hidden). 5. Some plants or varieties can be disease-free (latent).

Fourth, the virus control measures 1. Select anti-virus-resistant varieties. 2. Use virus-free seeds. 3. Control mechanical transmission. 4. Completely remove the weed host in the field, keep the environment as clean as possible, and reduce the source of poison. 5. Strengthen cultivation management. (1) Focus on strengthening the management of fertilizers and waters, applying sufficient base fertilizers, and increasing phosphate fertilizers to promote robust plants. During crop growth, attention should be paid to the prevention and control of aphids, planthoppers, whitefly, leafhoppers, thrips, and scale insects. (2) In the adult planting period, a variety of high-yield cultivation measures shall be comprehensively applied in accordance with the principle of “preserving soil moisture in the early stage, protecting fruits in the middle stage, and preventing decay in the late stage”. 6. Chemical control. Due to the virus's own characteristics, there is no cure in the world. The key lies in prevention and control. In the case of lighter virus, the following agents are recommended for prevention and treatment. The effect is acceptable. (1) Virus powder, raw solution, and dilute zinc; (2) Lobular mosaic virus net, good Pu, Fufeng zinc, Fufeng iron; (3) Bacteria poison grams, chlorophyll. As the severity of the virus, 3-5 days alternating medication. If the diseased plants account for more than 1/3, consider changing other vegetables.

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