Cucumber downy mildew is a devastating disease. Once it develops, it develops rapidly and it is also known as the "running horse." Because the early symptoms of lesions of downy mildew are very similar to those of keratoses, it is often confusing to misuse pesticides in the field and delay the best time for prevention and treatment. The symptoms and characteristics of the two are summarized as follows to help farmers and agricultural technicians correctly identify. I. Characteristics of symptoms of cucumber downy mildew and bacterial angular spot 1. The symptoms of cucumber downy mildew. Cucumber downy mildew can occur in every growing period of cucumber, and it is more common in the middle and late stages of growth. It mainly damages the leaves, and often occurs in the dewdrops or cofferdams of the greenhouse, forming a disease center, and then spreads rapidly. In the early stage of the disease, water-soaked dots form on the back of the leaves (obvious when there is dew in the morning, and then retreat after the dew has disappeared), and gradually expand into polygonal water-soaked spots. Afterwards, a gray-black mold layer grows on the back of the leaves. The early lesions of the leaves bleed green and gradually turn into yellow-brown necrotic spots, which are polygonal due to the limitation of veins. Eventually, multiple lesions connect to each other to cause the leaves to die. 2. The symptoms of cucumber bacterial keratoses. Cucumber seedling stage and adult stage can be disease. When the leaves are damaged, the initial stage of the disease is a water-immersed faded green spot. As the disease progresses, the lesions are polygonal and light brown. When wet, the lesions on the back of the leaves overflowed with white bacteria and pus, and the lesions often perforated or broken at the late stage of the lesion. Petioles, tendrils, fruits, and stem vines can also be affected. The lesions extend longitudinally along the stem sulcus to form streak spots. In severe cases, the diseased stems are longitudinally cracked, and the infected melon odor is smelly. Second, the difference between cucumber downy mildew and bacterial leaf spot 1. The pathogen is different. Bacterial keratopathy is a bacterial disease, while downy mildew is a fungal disease. There are essential differences between the two, and medication is of course different. 2. The lesion size is different. Bacterial keratopathy lesions are relatively small, generally 4-8 mm in diameter, lighter in color, grayish, and later lesions often perforated; downy mildew lesions are relatively large, generally 10-16 mm in diameter, with a darker color , yellow-brown, lesions are not perforated. 3. The light transmittance of the leaves is not the same. When the diseased leaves were picked off and viewed against the sun, the spotted spot had a light-transmitting feeling, while the downy mildew spot had no light-transmitting feeling. 4. The symptoms of the back of the leaves are different. When the humidity of the keratoderma is high, the water immersion is obvious, and sometimes the purulence of the milky pus can be seen. On the back rot of the downy mildew, there is a dark gray moldy layer. 5. Different parts of the hazard. Downy mildew generally only harms the leaves. In addition to damaging the leaves, keratoses also seriously damage the petioles, tendrils, fruits, and stem vines. The lesions expand longitudinally along the stem sulcus and form streak. In severe cases, the diseased stems are longitudinally cracked and infected. There is odor. 6. When the symptoms are inaccurate, a simple method can be used to identify the diseased leaves. Remove the diseased leaves and place them in a clean plastic bag. Drizzle in water for 15 hours at -20°C for 24 hours. The production is downy mildew, no black mold, and bacterial septic overflow. Disposable Latex Gloves,Disposable Vinyl Gloves,Nitrile Glove,Latex Glove ZHANGJIAGANG DINSHENGLIN TRADING CO.,LTD , https://www.dslhouse.com