The leaves of cucumber seedlings are delicate, weak in disease resistance, coupled with poor ventilation and seed bed ventilation, and high humidity, which can easily cause bacterial blight, anthrax, etc. Since anthracnose, blight, and bacterial diseases have similarities, downy mildew and bacterial angular spot disease are indistinguishable, and blight and damping-off are also easily confused, so the authors now report the symptoms of major diseases in these seedling stages. Make a description to help farmers identify and distinguish between friends, so as to take targeted preventive measures. Symptoms distinguish anthrax: anthracnose mostly appear semi-oval or near-circular pale brown lesions at the edge of the cotyledon, the pale yellow halos around the lesion are very obvious, slightly sunken, pink on the lesions under high humidity conditions The appearance of mucus is followed by a small dark spot with a roulette arrangement, which is usually very neatly arranged. Blight: Blast disease mostly starts with the "v" shaped inward expansion from the leaf margin, the lesion is nearly round or irregular, the water stains, the rouleaux is not obvious, many small black spots are scattered on the surface and completely scattered. Health, no law, does not secrete pink mucus under high humidity conditions. Blemishes: The newly emerged seedlings had no obvious disease on the ground, and the seedlings suddenly fell to death. The onset often starts with the dripping of sheds and quickly expands as if they are “shavedâ€. The seedlings near the surface of the excavated seedlings showed water-like yellowing, softening, contraction and linear appearance. When the humidity was high, white floc was observed in the diseased part. Blight: Mostly occur in the middle and late stages of nursery. At the time of onset, an oval-shaped brown lesion appeared at the base of the stem, the lesion gradually became depressed, and the lesion collapsed after one round of the stem. At the early stage of disease, the seedlings are wilted during the day and can be recovered at night. In severe cases, the plants wither and die. The difference between the disease and damping-off: First of all, blight is standing to die, and damping-off disease is suddenly fell to the ground to death, due to the sudden occurrence, the collapse of the plant began to maintain a bright green color; followed by high humidity, The diseased part of the blight showed a pale brown, sparsely arachnid-like layer, whereas the damping-off disease was a white layer of flocculosis. Downy mildew: The downy mildew leaves have no light perception and are mainly harmful to the leaves. The lesions are dark in color and are yellow-brown. They do not crack or perforate. The back of the diseased leaves has a black or purple gray mold layer and the lesions are relatively large. Fast, medium-term lesions are interconnected into patches, and the diseased leaves are irregularly immersed on the back. Keratoderma: Keratoderma leaves have light sensation, leaf spot pathogens mainly impregnate leaves and melon strips, sometimes harm melon vines; lesions are lighter in color, appear grayish, easily cracked at the beginning, form perforations; Milky white bacteria liquid, white film or white powder after drying; lesions smaller, slow dissemination; early morning sick leaves leafy water-like dip. Control methods Prevention and treatment of seedling spraying disease should pay attention to 3 points: First, should be sprayed with pesticides that do not produce phytotoxicity; Second, spray pesticides as far as possible with the choice to have two or more diseases; and third, spray should be strict Drug concentration and dosage to prevent phytotoxicity. Anthracnose and blight are caused by higher fungi. Therefore, there are many common points in the prevention and control. Similar to the use of pesticides, the ventilation and dehumidification can be conducted in a timely manner to enhance the temperature and humidity management in the shed to reduce the condensation of leaf surface and spit water. During the seedling stage, the leaves were sprayed with phosphorus-potassium power 750 times liquid or sea-green chlorophyll 1000 times to increase plant resistance to disease. In the early stages of the disease, blasts or anthracnose can be sprayed with bromine nitrite 750 times and penibular 1000 times, or 750 times plus one hundred thousand times, or up to 1000 times plus chlorophyll 1000. Double liquid prevention. The control of bacterial keratoses can be foliar sprayed with Wanjiafeng 750 times liquid plus chlorophyll 1000 times, or pure 750 times liquid plus Popo 1000 times, or 72% agricultural streptomycin, or 72% new Stemomycin 4000 times, or 60% of the bacteria net 800 times, or 70% can kill 1000 times. For the prevention of downy mildew, 69% of dimethomorph may be used at 1000 times, or 72% of Preclox 1000 times, or 70% of At Serox 1000 times, or 68.75% of Familia may be used as 1400 times, or 70% thiophanate-methyl Wettable powder 1000 times, or 64% antimony dampness powder 400 times, and can be added to 600 times liquid Lixin. Green Hunter No. 1 3000 times spraying plants, can prevent damping-off, damping-off, etc.; 70% Dukesson wettable powder 1000 times spray, can prevent damping-off and so on. China leading manufacturers and suppliers of Active Pharmaceutical Ingredient, Mupirocin , Mupirocin Calcium, and we specialize in Sodium Fusidate, Fusidic Acid. Active Pharmaceutical Ingredient, Mupirocin, Mupirocin Calcium, Fusidic Acid, Sodium Fusidate Manufacturer Fuzhou Contay Biotechnology Co., Ltd , https://www.contaybio.com