1, the main performance: 1 migraine. Unbalanced fruit development, normal development on one side, and stagnation on the other, are due to poor ovary development, uneven pollination, and poor fertilization. 2 flat melons. The horizontal diameter of the melon is larger than the longitudinal diameter, so that the melon is flat. The low temperature of the female flower or the melons in the low-potential female flower is easy to form a flat melon. 3 sharp mouth melon. The pedicel part of the melon became thinner and the stem part expanded. Insufficient supply of nutrients during fruit enlargement and high-spotted fruit set-up make it easy to form sharp-edged melons. 4 Hulu melons. The top of the melon swells close to the flower pedicle, while the smaller stem close to the fruit stem shows a gourd shape, which is caused by poor fertilization.
2. Preventive measures: 1 In the 2-4 true leaf stage of flower bud differentiation, avoid the influence of low temperature (night temperature above 13°C), and the fertilizer and water supply is appropriate. 2 Control the fruit setting, select the first 2-3 female flowers to stay in the melon. 3 Collect female flowers of different plants at 8-10 am for artificial pollination. Apply pollen uniformly to the stigma. The amount of pollination should be sufficient. The pollination temperature should be maintained at 20-30°C to increase pollen activity and promote fertilization. 4 In order to correct the shape of the fruit in a timely manner, turn the young melon and perform at least 1-2 times during fruit development. 5 Watermelon meets the continuous dry weather in the fruit period. It is necessary to replenish the fertilizer and pay attention to the application of phosphorus and potassium fertilizers. It is best to use under-film hose drip irrigation.
Second, empty fruit
1, the main performance: quail cracks, and the formation of gaps. In addition to the production of empty fruit in addition to the large fruit-shaped varieties themselves, fruit set under low temperature conditions, excessive nitrogen fertilizer caused by fruit in the case of prosperous, prone to empty fruit. The main reason for the empty fruit production is the inconsistent growth speed of the peel and the melon.
2. Preventive measures: 1 Early cultivation of watermelons in greenhouses should be based on small and medium-sized fruit varieties, such as Xiaolan, Te Xiaofeng, and early spring ruby. 2 The fruit setting period is 25-35°C during the day and 18-20°C at night. Under conditions of low temperature or drought, fruiting nodes are postponed. 3 timely pruning to prevent running vines, the general use of three vine pruning, that is, in addition to leaving a main vine, then select the remaining two sub-vines, the remaining side vines removed. 4 When the size of the watermelon egg is thinned, leave one for each batch of melon.
Third, cracked fruit
1, the main performance: from the vine to produce cracks, young fruit to maturity can occur. Usually thin skin varieties and small varieties are prone to occur. In the early stage of fruit enlargement, the temperature was low, and after the growth stopped, it quickly expanded and caused cracking. From the late fruit enlargement period to the harvest period, the amount of watering is not appropriate, and the water absorption and the evaporation amount are not balanced and cause fruit cracking. In a certain stage of fruit development, due to drought, there is little soil moisture, and the development of fruits is hindered. Suddenly a large number of water injections cause the soil water to increase rapidly and cause fruit cracking.
2, preventive measures: 1 select the appropriate species. 2 The initial temperature of fruit enlargement should be kept at least above 20°C and appropriate amount of water should be used. 3 During fruit enlargement period, it encountered high temperature and dry weather. The greenhouse film was removed, the top membrane was kept, and flood irrigation in the field was prohibited. 4 Collisions are reduced during fruit bagging, picking, and transportation.
Fourth, umbilical rot fruit
1, the main performance: the top of the fruit depression, into a dark brown, when the humidity is high, the case of saprophytic fungi will appear black moldy. Water deficiency and calcium deficiency during fruit enlargement are prone to umbilical rot.
2. Preventive measures: 1 Apply organic fertilizer and calcium superphosphate, apply 3,000 kg per mu, and superphosphate 50 kg. The entire surface of the mulch is covered with a plastic film to promote preservation. (2) Balanced supply of fertilizer, drought-resistant weather timely irrigation under film. 3 foliar spray calcium solution or 1% superphosphate solution. 4 Note that use 75% chlorothalonil 600 times, 70% thiophanate-methyl 1000 times to prevent disease.
Five, poor quality fruit
1. Main performance: The flesh around the melon skin or the pulp around the seed is water-stained, purple-brown to brown, and when the seed is serious, the flesh around the seed turns purple and ulcerated and cannot be eaten.
2, preventive measures. 1 Fruits should be protected from sun exposure. If necessary, weeds can cover fruit. 2 Increase the application of organic fertilizer during the expansion of watermelon fruit, and apply phosphorus and potassium fertilizers, timely watering or drip irrigation under the membrane to prevent premature aging. 3 Use 70% imidacloprid 5000 times in a timely manner to prevent transmission of insects, aphids, and whiteflies. Spray 20% of virus A or 3.95% of virus Bike 500 times to prevent virus disease.
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