In recent years, Qian'an City, a large greenhouse cucumber planting area, cucumber raw and cooked edible, market sales, especially in winter has been favored by consumers.
Cucumber growth requires high humidity and temperature, the conditions are easily induced cucumber diseases occurred, and the symptoms of some diseases and extremely similar, if not properly identify will control time delay, cause serious loss to cucumber production.
1 cucumber downy mildew.
1.1 the incidence of symptoms. Early onset of leaf water stains like light green spots, the extended polygonal, when humidity is big lesion on the back was downy mildew like, mycophenolate layer of black ash, serious disease leaves yellow and died.
1.2 pathogenesis. Suitable temperature of 16 degrees Celsius to 24 degrees Celsius, the appropriate incidence of humidity of 85% or more, the temperature is higher than 30 degrees Celsius or below 15 degrees Celsius can inhibit the disease occurs, the humidity is less than 60% bacteria spores can not produce.
1.3 methods of prevention and control. Selection of disease resistant varieties; implementation of rotation. Chemical control: alternative use 25% metalaxyl WP WP 500 ~ 600 times liquid, 58% metalaxyl spirit mancozeb wettable powder 600 times liquid, 72% mancozeb wettable powder of 600 ~ 800 times liquid spray.
2 cucumber angular leaf spot disease.
2.1 the incidence of symptoms. The early onset of leaves were water soaked spots, gradually expanding polygonal brown spots, but no black frost layer. The stem and fruit victims, at the beginning of a water soaked spots, white fungus with the pus, fruit spots can spread to seed.
2.2 pathogenesis. The pathogenic bacteria with plants or seeds in the soil in the winter, the survival period of up to 2 years. Seed borne fungi and post emergence cotyledons disease appear pus bacteria, with insects, water and spread of invasive parts pores, wound and holes, low temperature, high humidity and cropping the serious disease.
2.3 methods of prevention and control. Selection of resistant varieties; with 55 warm water soaking for 15 min or 100 times with acetic acid soaking 30 min sterilization. The incidence of light with the use of fluorine and silicon in the 600 ~ 800 times of the liquid spray, 5 ~ 7d 1 times. Severe use of fluoride and silicon, 300 times the liquid spray, 1 times the liquid spray, 3 D drug use. At the same time with the occurrence of downy mildew can be used 50% a cream of copper powder, 60% 100 bacteria through the wet powder 500 times the liquid spray.
3 cucumber wilt disease.
3.1 The incidence of symptoms. Leaf injury after the bacteria from the new leaf edge inward invasion, forming a "V" shape lesion, victims of stems often amber or transparent colloid logistics, scattered a lot of black students. In the later stage of the disease leaves are broken and fruit dry rot.
3.2 pathogenesis. Bacteria, mainly to students spores or perithecia with diseased plants overwinter in the soil. Seed can be sick spread, invasion part of stoma and wound and holes. Bacteria hi warm and humid conditions, the appropriate temperature of 20 ~ 25 degrees Celsius, the relative humidity of 85% or more.
3.3 methods of prevention and control. The implementation of crop rotation, with 10% Difenoconazole azoles water powder granule 1 500 times liquid or 70% mancozeb 600 times liquid mixed 40% chlorothalonil suspending agent 1 000 times liquid spray.
4 cucumber scab.
4.1 The incidence of symptoms. This is a devastating disease that can harm the leaf, stem, melon and fruit, especially in young leaves and young fruit growth point to suffer the most. Seedling disease, cotyledon showed nearly circular white spots, after full leaf dry. When infected stems were water soaked green diamond spot, after dark decay. Ye Bing, melon infected middle sag, easy to crack, the surface of black mold layer.
4.2 pathogenesis. Bacteria in diseased plants, soil and seeds in winter, after the onset of bacteria by rain and air borne repeated infection, when the temperature of 20 DEG C ~ 22 degrees C, relative humidity of 90% above the onset of severe.
4.3 methods of prevention and control. Seed sterilization, with 55 DEG C ~ 60 DEG C seed soaking in warm water for 15 min or more than 50% carbendazim wettable powder 500 times fluid soaking for 20 min, after the washing clean germination. Chemical control with 50% carbendazol wettable powder of 1 000 times liquid mixed 80% green Hengdaisen, manganese, zinc, wettable powder, 1 000 times liquid spray.
5 cucumber powdery mildew.
5.1 the incidence of symptoms. Early leaf white pink, and gradually expand the pink round spots, serious when appear a large white area, leaf as long a layer of white hair, then changed from white gray white, and finally leaves lost function of manufacturing nutrient.
5.2 pathogenesis. Cucumber powdery mildew by air or rain spread, after the onset of lesions produced conidia, in the field of multiple infection. The disease is both warm and wet and dry, the onset of the most suitable temperature 16 ~ 24 degrees Celsius, the most suitable relative humidity of 75%, the temperature is higher than 30 degrees Celsius, humidity more than 95% of the disease is inhibited.
5.3 methods of prevention and control. At the early stage of the disease, alternating with 20% Triadimefon EC 1500 times fluid, 15% Triadimefon ketone wettable powder 1 500 times liquid, 50% methyl sulfur bacteria spirit wettable powder of 800 times fluid and 75% chlorothalonil Qing wettable powder 600 times liquid spray, 6 ~ 7 d, spray 1 times, St 3 ~ 4 times.