Identification and Control of Fusarium Wilt of Cucumber
Cucumber is the main vegetable species planted by vegetable growers. In recent years, due to the occurrence of cucumber wilt disease, the income of vegetable farmers has decreased. The incidence of cucumbers in greenhouses has become an important factor that affects the yield and benefits of cucumbers. Prevention and control work should be done in production.
First, harm symptoms and identification
Cucumber fusarium wilt is a soil-borne disease that mainly invades the vascular bundles in the stem base of cucumbers. The pathogens propagate and spread in vascular bundles, poisoning host cells by blocking vascular bundle conduits and secreting toxic substances, destroying the host's normal absorption and transport function, and making nutrients and moisture. Transport blocked.
Cucumber fusarium wilt can occur during the whole growth period. After the flowering result, the incidence is heavier, and the most fruitful period is the melon period. The most typical symptoms are wilting. The early stage of disease manifests as the leaves gradually wilting from the bottom upwards, appearing as water-deficient, more obvious at noon, and recovering sooner or later. After a few days, the whole leaf withered and wilted, no longer returning to normal, stem base Often contracted, roots brown rot, stem base often longitudinal crack, disease stem longitudinal inspection, its vascular bundle was brown. In moist conditions, the surface of the diseased area often produces a white or pink mold layer.
Second, the incidence of the law
Cucumber wilt is a fungal disease. In the soil and fertilizer, chlamydial spores or mycelium are allowed to overwinter in the soil with the diseased plant residues, but they can also survive winters in unfertilized fertilizers or on seeds, greenhouses, and greenhouses. The bacteria can survive in soil. ~6 years. When the conditions are appropriate in the following year, the initial infection is formed, and the conidia are produced in the diseased part, and can be transmitted through the soil, seeds, fertilizers, agricultural implements, and irrigation, etc., and the roots or root tips of the stems invade the tissues into the gaps between the cucumber cells. And intracellular growth, and repeated infections. After entering the vascular bundle, the plants wilted and even the whole plant died of poisoning. The suitable soil temperature for onset is 20°C～23°C, and the disease is less than 15°C or higher than 35°C. When the average temperature is 18°C ​​to 25°C, relative humidity is higher than 85%, and soil moisture is high, it is easy to develop. Continuous cropping, poorly drained clay land, or the use of organic fertilizers that are not adequately decomposed, the roots of the plants are stunted, the weather is hot and humid, or the seedlings are aging, the planting density is too large, and insufficient nutrients are susceptible to disease.
Third, comprehensive prevention and control technology
1. Use resistant varieties. The resistance to fusarium wilt among cucumber varieties differed significantly. Zhongnong 5,7,8, Jinchun 3 and other varieties are more resistant to disease and can be selected according to the situation.
2. Seed disinfection. Seed soaking in warm water at about 55°C for 15 minutes, or with 50% carbendazim wettable powder, with a dose of 0.1% of the seed weight.
3. Pay attention to the mouth arrangement. Rotation and rotation of non-melon vegetables for more than three years will reduce the number of germs in the soil.
4. Pay attention to soil disinfection. Use seedling-free seedlings, especially nursery bed soils, to use seedlings that have not experienced blight. Treated with 50% carbendazim 8 grams per square meter. Before planting, use 50% carbendazim per acre 2 kg, mixed with 30 kg of fine dry soil, evenly spread into the planting hole after mixing.
5. Grafting and disease prevention. Grafting and disease prevention generally use black seed pumpkin as the rootstock grafted cucumber. Black-skin squash has developed roots, strong ability to attract fertilizer, strong growth potential, strong immunity to Fusarium oxysporum, and obvious effect of increasing yield. The grafting site of cucumber seedlings should be more than 2 cm above the ground, which can cut off the breeding of adventitious roots. The interface between the grafted cucumber and the pumpkin at the time of colonization must be at a certain height from the ground to prevent the cucumbers from touching the ground and then grow new roots, thus losing the function of grafting and disease prevention.
6. Cover the roof to prevent the disease. After the temperature rises in the spring, greenhouses retain the shed film and skirt film. Usually, the shed film is rolled up and the shed door is opened. When it rains, the shed film is closed and the shed door is closed to prevent rain and humidity, and to prevent melons from wilt and other diseases. Disease transmission.
7. To strengthen the cultivation and management. Soil testing, formula fertilization, and application of fully decomposed high-quality organic fertilizers. In agricultural operations, attention should be paid to reducing wounds and raising the level of cultivation and management. Strictly prevent flooding, so that small water pouring. Appropriate amount of cultivator, improve soil permeability, make roots strong, and enhance disease resistance. Cucumber melon period should be applied in stages, apply fully decomposed organic fertilizer, should not use uncomminuted human waste compost; increase cake fertilizer, phosphorus and potassium fertilizer and slaked lime, in order to improve soil physical and chemical properties. Remove diseased plants in time during growth. After harvesting, attention should be paid to the collection of residual diseased plants that are burned and turned over to reduce the spread of blight.
8. At the beginning of the disease or before the onset of the disease, the root canal treatment is performed. 50% carbendazim 500 times, 70% thiophanate-methyl 50% carbendazim (1:1) 1000 times, 30% hymexazol 500-1000 times, 50 % Bromobromide isocyanuric acid + nutrients 1500 ~ 2000 times liquid, agricultural resistance 120 water 200 times liquid, etc., in the irrigation around the roots, each hole 300 ~ 500 ml, can also be sprayed stems, but also available drug stem. Every 5 to 7 days, 2 to 3 times in succession, the diseased plants should be watered around. Care must be taken to prevent and control cucumber wilt disease early prevention and early management, otherwise the control effect will be poor.
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