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The difference between bacterial diseases, fungal diseases and viral diseases
1, fungal diseases
Diseases caused by fungi can show signs such as spots, wilting, and deformities. However, bacterial diseases can also cause the same symptoms. The main difference is that the fungal diseases can see spider-like or flocculent mycelium at the site of the disease, and some have abnormalities such as sclerotia to mycelium. There are various kinds of mildew on the surface of the diseased part, which is an important feature for identifying fungal diseases. Where fungal diseases occur, no matter what part of the disease occurs, the symptoms are manifested, and hyphae and spores are produced under humid conditions. This is the main basis for judging fungal diseases. For example, cucumber powdery mildew, white spots appear on the lesions on the leaves. Another example is melon and tomato gray mold, gray mold on the damaged leaves, residual flowers and fruits. Common fungal diseases are: downy mildew of vegetables, powdery mildew, gray mold, blight, blight and so on.
2, bacterial diseases
Diseases caused by bacteria, mainly spots, ulcers, wilting, necrosis and rot. Necrosis, rot, and deformity are the consequences of bacteria destroying cell wall tissue. On the leaves of its reticular veins, the lesions showed acute necrotic plaques with polygonal plaques and yellow halos around the lesions. The lesions on the hypertrophic tissue or fruit are mostly round. On soft, juicy tissues, tissue death is perishable. Some parts of the lesions occur after the promotion of lesions, the formation of tumors, this phenomenon occurs mostly on the roots or stems. Atrophy is the result of cells infecting vascular bundles and can occur locally or in whole. Cellular diseases have no hyphae or spores, and there is no mildew on the surface of the lesions, but there are bacteria pus (except root cancer bacteria) overflowing, and the surface of the lesions is smooth, which is the main basis for diagnosing bacterial diseases. For example, cucumber bacterial angular spot disease and similar symptoms of downy mildew, the leaves have polygonal lesions, which are easy to be confused, but downy mildew has black mold on the lesions in the wet, while the angular spot disease does not.
3. Viral diseases
Viral diseases are mostly chronic diseases of the whole plant. The external appearance symptoms are often mosaic, chlorotic, ring-shaped, dead spots, clumps and leaf shrinkage. The mosaic is characterized by leaf shrinkage and yellow-green interlaced spots. The yellow leaves are particularly bright, and the green leaves are dark green. The yellow parts are all concave. Viral diseases are only symptomatic, which is confused with fungal diseases and bacterial diseases. The difference is that the occurrence of viral diseases is obviously spread from point to point. The disease appears on the diseased plants, often starting from the top and then expanding to other parts of the plant. The spread of the virus depends on insect transmission, juice contact and graft infection. Viral diseases are aggravated under conditions of high temperature and drought. Non-invasive diseases occur more evenly and do not exhibit an expansion from point to point. The diseased plants are often infected with the whole plant, and the plants cannot be infected. The occurrence of diseases is closely related to factors such as adverse environment.
Cucumber powdery mildew