Because the climate is different in different places, I want to know the suitable temperature, fertilization and diseases and insect pests in each stage of watermelon growth. How to use cow dung?

Watermelon spring sowing is generally from late March to early April, and a large number of watermelons are listed from late June to the end of July. After August, the watermelon market is dominated by Henan pumpkins. From September to 10, only a few northern melons entered the market, and the price was high and the quality was poor. Planting watermelons in autumn can not only meet people's demand for high-quality watermelons in the off-season market, especially during the 5438+00 National Day from the end of September to the beginning of June, but also obtain better economic benefits because of the high market price. However, because the cultivation techniques of watermelon in autumn are more difficult than those in spring, especially the seedling raising techniques are difficult for farmers to master for a while, this paper introduces the autumn cultivation techniques and measures of watermelon in open field.

Shao is like this:

1, variety selection:

Because of the high temperature and strong sunshine in autumn, the growth period of watermelon is relatively shortened, and the supply period is not the season for mass consumption, so we must choose varieties according to market demand and output. It is best to choose high-quality gift watermelon varieties with early maturity and small round fruit, such as Hongxiaoyu, Huang Xiaoyu, Jin Fu and Xiaoyuhong seedless. Or medium-ripe, medium-early-round and medium-fruit-quality watermelon varieties, including both seedless and seedless watermelon varieties, such as Hongda, Mihong seedless, Mihuang seedless and so on.

2. Selection of melon fields

Sandy loam or loam with convenient irrigation and drainage and good soil permeability should be selected. Paddy field needs 3-5 years rotation, and dry land needs 5-8 years rotation.

3. Cultivate strong seedlings

3. 1 sow in time

Sowing time should be from mid-July to early August, so that it can be listed from the end of September to the beginning of 10 to meet the supply of high-quality watermelons in the holiday market.

3.2 Cultivate strong seedlings:

Cultivating strong seedlings is the key to watermelon cultivation in autumn. From mid-July to early August, it is a hot and dry season in our province, and it is difficult to raise seedlings. If the seedbed is not carefully managed, it will cause burning seeds, burning seedlings or forming high seedlings, reducing the resistance of seedlings and watering easily. It is best to use nutrition pots to raise seedlings centrally, which is convenient for seedbed management. Sowing can adopt two methods: accelerating germination after soaking seeds or not accelerating germination. Seedless watermelon is best sown by accelerating germination. After sowing, cover the seedbed with a small arch film and cover it with sunshade net or grass curtain to prevent the seedbed from burning due to excessive temperature. The bed temperature is controlled at 32-35℃ during the day and 28-30℃ at night. When the bed temperature exceeds 35℃ during the day, both ends of the small arch membrane should be opened for ventilation and cooling. After the seeds are arched, remove the small arch film and shade with a sunshade net or grass curtain. Seeds should be "capped" in time after emergence, and the cover should be removed in the morning and evening and cloudy days, and the shade should continue in sunny morning. After 5 pm, when the two leaves of the seedling are flush, spray 50-1000 mg/1000 g of paclobutrazol solution until the cotyledons are wet and not dripping, and then carry out routine management. In this way, the hypocotyl of melon seedlings is short and thick, which is not in vain.

4, timely colonization

7- 10 days after sowing, when the seedlings grow real leaves, they are planted in the field. At this time, the root system of seedlings is narrow, the root system is not easy to be damaged and the survival rate is high. Before planting, a bottom water irrigation can be carried out according to the soil moisture in Gua Tian to ensure sufficient soil moisture and ensure the survival of seedlings. Planting should be done in cloudy or sunny afternoons. After planting, each plant should be immediately watered with 0.5 kg of 3‰ compound fertilizer water, and if there is no irrigation, more water should be poured. If the seedlings are found wilting due to high temperature the next day, they should be watered again in the afternoon. Immediately cover with plastic film with film width 1 m. In the afternoon, cover with plastic film, immediately break the film, put the seedlings and seal the nest. The plant spacing of fruit-type gift watermelons with low planting density is 0.45×2m, which is equivalent to about 1.500 plants per 667m2, and the plant spacing of middle-maturing and early-maturing varieties is 0.5×2m, which is equivalent to planting more than 660 plants per 667m2 in single row and ground cultivation.

5. Tian Tuan management

5. 1 Rational fertilization

Watermelon grows rapidly in autumn, the growth period is relatively shortened, and the demand for fertilizer is quick-acting and relatively concentrated. In order to improve the quality of watermelon, 50-75 kg of decomposed cake fertilizer (dry cake amount), 2000 kg of decomposed pig manure or soil miscellaneous fertilizer, 35 kg of potassium sulfate compound fertilizer and 5 kg of urea were applied in the border according to soil preparation, and 5 kg of potassium sulfate compound fertilizer was applied in two or three times according to seedling potential combined with irrigation. When the young fruit eggs are large, the swollen melon is used with irrigation water. Depending on the growth of melon seedlings at fruit maturity, potassium dihydrogen phosphate, urea and urea should be sprayed appropriately, and foliar fertilization should be carried out after 4 pm on cloudy or sunny days.

5.2 Rake the whole branch flat and spread it with straw.

Watermelon grows rapidly in autumn, and its growth potential is not as strong as that in spring. In order to increase functional leaves and promote the expansion of young fruits, two vines were used for trellis cultivation and three vines were used for climbing cultivation. In autumn, the temperature is high, the water evaporates quickly, and the soil water retention capacity is poor. Therefore, it is appropriate to spread 5cm thick straw or thatch on the border for creeping cultivation, which is not only beneficial to keep the soil moist and fix the melons and vines in the field, but also to prevent the soil from hardening and the young fruits from being burned by high temperature.

5.3 Artificial pollination, selecting melons to keep seeds.

In order to improve the fruit setting rate and commercialization of autumn watermelon, it is suitable for artificial pollination and seed selection. Generally, the second to third female flower on the main vine or the second female flower on the side vine bears fruit. When the young fruit is big, the fruit is thinned and the melon is left. Set small fruit-type gift watermelons, 2 fruits per plant, medium fruit-type varieties for creeping cultivation, and leave 1 fruit per plant. Select young fruits with correct fruit shape, moderate fruit setting position and good fruit color, and remove all the remaining fruits.

5.4 Reasonable irrigation

Autumn in our province is a season of high temperature and little rain, so irrigation must be carried out in time according to soil moisture and plant growth to ensure the normal growth of melon seedlings, especially in the period of rapid expansion of young fruits, which requires a lot of water and must ensure sufficient water. Irrigation must master the dry and wet conditions of soil to avoid flooding and epidemic diseases.

5.5 Pest control

When watermelon is cultivated in autumn, there are generally fewer diseases, mainly virus diseases, which are related to the occurrence of aphids, so preventing aphids is the most effective method to prevent virus diseases. Anthrax also occurred in the later stage. 65% mancozeb 600 times solution and 70% thiophanate-methyl 800- 1000 times solution can be sprayed alternately for control.

insect pest

The main pests that harm autumn watermelon are yellow cucumber, aphid, Spodoptera litura and tobacco budworm. In prevention and control, we should adopt the method of prevention first and comprehensive prevention and control. Weeds in and around the field should be cleared, and at the same time, poisonous bait and artificial trapping methods should be used to eliminate early pests. 90% crystal trichlorfon or 50% dichlorvos EC 1000 times can be sprayed for the control of zucchini. To control melon aphid, Spodoptera litura and Pieris rapae, 40% dimethoate EC 1000 times, 20% pyrethroid, 2.5% deltamethrin 3000 times or 2% Pieris rapae microemulsion 1000- 1500 times can be sprayed alternately, or

Cultivation techniques of small fruit seedless watermelon Xiaoyuhong in greenhouse

Xiaoyuhong, a small seedless watermelon, is the only watermelon variety that has passed the national examination. Suitable for protected cultivation in early spring, open cultivation and delayed cultivation in summer and autumn. It has the characteristics of early maturity, small fruit, thin skin, excellent quality and high output value. The following introduces the key points of high-yield cultivation techniques in Xuefeng Xiaoyuhong seedless greenhouse:

First, raise seedlings

(1) Seedbed preparation. The seedbed should be located in the leeward and sunny place with sufficient sunlight and convenient drainage. Use plastic nutrient pots to raise seedlings intensively, and the nutrient soil should be fertile and loose, free from pests and weeds. Proportion: paddy field topsoil 65%, decomposed pig cow dung 35%, ternary compound fertilizer 0. 1%, mixed evenly. After the nutrient bowl is filled with soil, it is arranged on the seedbed for sowing.

(2) seed treatment. Xiaoyuhong seedless watermelon, like ordinary seedless watermelon, has to undergo seed drying, seed soaking, disinfection, shell breaking and germination accelerating before sowing. Because the seeds are small, mechanical shell breaking is easy to damage the seeds, so it is appropriate to gently bite the small mouth with your teeth. Then put it into a higher temperature of 32-35℃ to accelerate germination.

(3) The earliest suitable sowing date is about early February, and the sowing date of solar greenhouse cultivation (winter warm greenhouse) in North China can be advanced appropriately. The seedbed is set in the greenhouse or greenhouse, and the film in the greenhouse and room is tightly covered and compacted before sowing. In the afternoon before sowing, use a watering can to drench 0. 1% aqueous solution of Tobuzin through a plastic nutrition bowl. Sow the seeds the next day according to the conventional sowing method. Sow 1 bud in each pot, and then cover with 0.5㎝ thick fine soil. After sowing, spread 1 layer of plastic film on the bed surface to increase the temperature and keep it moist. Then immediately insert the bamboo arch to cover the agricultural film, cover it tightly, and clean the drainage ditch around the seedbed and greenhouse.

(4) Seedbed management. The central task of seedbed management before emergence is heat preservation and rodent prevention. The temperature of seedbed after sowing should be adjusted to 30-35℃ and proper humidity should be maintained at the same time. When the melon buds are covered with soil, the plastic film should be removed in time. After 70% seedlings emerge, the hulls should be carefully removed when the seeds are wet in the morning. Immediately after "hole sowing", cover the arch shed membrane to keep moisture and raise temperature, and continue to promote seedling emergence. After 1-2 days, carry out the second "hole sowing". After emergence and before 1 true leaves appear, attention should be paid to lowering the bed temperature to 20-25℃ to prevent the seedlings from growing into tall seedlings due to high temperature and high humidity. Others are the same as general seedless watermelon management.

(5) Grafting and seedling raising. Grafting and disease prevention measures must be taken in continuous cropping cultivation of watermelon in greenhouse. Pay attention to the best grafting time when the true leaves of watermelon scions begin to appear. The grafting method is the same as the general seedless watermelon grafting method, and the grafting should be carried out on sunny days as far as possible.

Fourth, the preparation of the venue. Planting greenhouse plots should be selected in areas with high and dry terrain, convenient irrigation and drainage, deep and loose soil layer and medium fertility. Before winter, the soil should be deeply ploughed for more than 20㎝, and the second ploughing should be carried out 10- 15 days before planting. For scaffolding cultivation, the line spacing of 1m is taken as the boundary, and the ground climbing cultivation is adopted, and the line spacing of 1.7m is taken as the boundary. The application amount of base fertilizer is slightly less than that of seedless watermelon with big fruit. Generally, 2000-2500㎏ or 2500-3000㎏ soil mixed fertilizer, 100㎏ cake fertilizer and 25-30㎏ ternary compound fertilizer are applied every 667m2 (mu). After the fertilizer and soil are mixed evenly, the ditch is closed and the height of the border is 20㎝. 7-8 days before planting seedlings, the border is completely covered with plastic film, and the arch frame of the greenhouse is set up and covered with plastic film.

Second, seedling planting and planting density. 1-2 before planting, the nursery nutrition bowl should be filled with water, and the plastic film at the planting position of melon bed should be marked with the word1"x" or punched with a puncher, and the grafted seedlings should not be buried in the soil. After planting, each plant is watered with 0.2%-0.3% compound fertilizer water or 0.5L (liter) diluted decomposed human excrement and urine water, and then the hole is sealed with soil. In order to overcome the low temperature in early spring and improve the survival rate of seedlings, a small arch shed can be added to the rows of seedlings.

Planting density: 600-700 vines should be planted every 667m2 (mu) when two vines are planted on the ground, and 500-600 vines should be planted when three vines are pruned. When pruning two grapevines on the scaffolding, plant 1 100- 1200 plants every 667m2 (mu).

Third, field management after planting.

(1) Temperature and humidity management in greenhouse. 5-7 days after planting, the greenhouse and the small arch shed are sealed, and the greenhouse temperature is kept at 25-28℃ during the day and not lower than 15℃ at night, which promotes the delayed emergence of seedlings. If the temperature is higher than 35℃ during the day, try to shade and cool down. In case of strong cold air, straw curtains or paper curtains should be added to the small arch shed in the greenhouse. Don't irrigate in the slow seedling stage to prevent lowering the ground temperature.

(2) Trimming and winding. When there are 5-6 true leaves, leave 5 leaves for coring. Generally, the double vine pruning method is adopted. When the vines grow to 40-50㎝, select and leave two robust vines with similar length and size. The remaining vines and the sun vines growing on the next two branches should be picked off in time, and 10- 15 leaves can be topped at the fruit-setting festival. Scaffolding cultivation and branching should be carried out until the scaffold is full. After the watermelon expands, the sun vine protruding from the top should be decided on the principle of not shading.

When climbing on the ground, vines must be coiled. When the vine grows to 80- 100㎝, firstly, the vine is led to the left and right oblique rear of the plant rhizosphere, and then bent into a semicircle, so that the melon vine faucet rotates forward again, and the curvature of the vine bend is larger, otherwise, the curvature is smaller, and the vine spacing is kept at 15-20㎝, so as to make a growth point.

(3) Erect and tie the vines. In scaffolding cultivation, when the plant grows to 50-60㎝, it should stand upright and tie the vines in time, and each vine should use a pole or nylon sling. When tying vines, use the "8" button, and the vines should be firmly tied to the vertical pole to prevent them from falling off. At the same time, we should pay attention to the management of vines, rationally allocate leaves and melon embryos, and do not break tender vines, female flowers or melon embryos; Be careful not to touch the melon when you tie the vine later. Binding vines and pruning can be combined.

(4) Artificial pollination and fruit setting promotion. Watermelon is cultivated in greenhouse in early spring. Because there is no wind in the greenhouse, there is little insect activity. During this period, the temperature in the shed is low, especially in rainy days, and the amount of loose pollen of pollinated varieties is small, so artificial pollination must be carried out. At the same time, spraying or smearing cucurbitacin can ensure good fruit setting and achieve the goal of 1 plant. Generally speaking, when pollination begins, the second female flower of the vine opens. It is difficult to set fruit in rainy days, so the female flowers can be covered with paper caps for pollination to improve the fruit-setting rate, and the fruit-setting can also be promoted by "sitting melon spirit". Pollination time is usually carried out at 8-9 am, and rainy weather can be postponed appropriately.

(5) Water and topdressing. After the seedlings are planted and before the vines are stretched, the watering amount should not be too large, so as to improve the ground temperature and make the seedlings strong. Do not water during flowering and fruit setting. When young melons grow to the size of eggs, they should be irrigated with small water frequently to keep the ground moist. After the watermelon is shaped, water is poured every 5-7 days, and water is stopped 7 days before harvesting, so as to promote the maturity of watermelon and improve its quality. The flowering period of watermelon in south China is rainy, so it is not allowed to open the ventilation seam on the roof in rainy days. Watermelon expansion period and fixed period, in the long drought and rainy weather, pay attention to the use of greenhouse film to prevent rain and prevent fruit cracking.

After the melon seedlings are planted, before the vines are inverted, they are sprayed with 0.4% ternary compound fertilizer water or dilute human excrement and urine for 2-3 times. When climbing on the ground, when the length of melon vines is 40-50㎝, shallow furrows should be opened at a distance of 60-70㎝ from the planting holes of melon vines for topdressing. Scaffolding cultivation: shallow furrows can be opened on both sides of melon ridges before the scaffolding and after the small arch shed in the greenhouse is dismantled, and 20㎏ ternary compound fertilizer can be applied every 667 ㎏ (mu). When the fruit eggs are large, 20㎏ ternary compound fertilizer (combined irrigation) can be applied every 667 ㎏ to promote long melons. In the middle and late stage of fruit development, in order to prevent premature aging, 0.2% potassium dihydrogen phosphate or foliar treasure can be sprayed on the leaves around 5 pm on sunny or cloudy days. If the second crop of melons is harvested, ternary compound fertilizer 1 5/667 ㎡ (mu) should be applied when1batch of fruits is about to be harvested and the second batch of fruits is sitting alive, so as to keep the normal growth of the second batch of fruits.

Fourth, choose melons to hang melons. Fruits with 2-3 female flowers should be selected. When the melon is as big as an egg, young melons with long stems, rapid development, no damage, no deformity and uniform size are selected, and two fruits per plant are targeted at/kloc-0. If the melon grows to the mouth of the bowl and weighs about 0.5㎏, it will hang up.

Five, pest control. The main diseases of seedless watermelon in greenhouse are damping off, anthracnose, Fusarium wilt and Fusarium wilt. Non-continuous cropping land and grafting cultivation are mainly selected to prevent Fusarium wilt. Other diseases can be controlled with 70% thiophanate-methyl 500-800 times solution, 50% zineb or watermelon herbicide 500 times solution and 75% chlorothalonil wettable powder 600 times solution. Generally, spraying 1 once every 7 days in sunny days, once every 3-4 days in rainy days, and spraying again 2-3 times in case of rain can achieve good control effect. The main pests are black cutworm, cucumber yellow and aphid, which can be controlled by methomyl and trichlorfon in the early stage and omethoate or dichlorvos in the later stage.

Sixth, harvest. Seedless watermelons sold locally should be harvested at eight maturity, while those shipped abroad should be harvested at eight maturity.

Causes and countermeasures of difficulty in setting fruit at high node position of watermelon female flowers

According to farmers' feedback and field investigation, seedless watermelons and seedless watermelons in some areas of our province have two phenomena of high node position and low fruit setting rate this year, which seriously affected the yield and quality of watermelons and dampened the enthusiasm of watermelon farmers. According to many years' experience, consulting relevant information and consulting relevant experts, aiming at this year's climate characteristics, this paper discusses the causes of the above problems and puts forward countermeasures in order to provide technical support and help for the majority of melon farmers.

First, the high temperature and humidity in the early stage of watermelon will cause fewer female flowers, more male flowers and higher female flowers.

Physiologically speaking, watermelon gradually differentiates and germinates after two real leaves, and with the development of leaves and vines, Cheng Xiong flowers and female flowers gradually develop. The node position of female flower formation is influenced by variety, climate and cultivation conditions, among which temperature, humidity, light and hormone drugs have the greatest influence on flower organ formation. Generally, when the true leaves of watermelon in the open field reach 6-8, it will enter the stage of female flower differentiation, so the weather in this period will directly affect the position of female flower and its future yield.

Effects of 1 and temperature on seed germination and differentiation

Experiments show that temperature is directly proportional to the development of male flowers and inversely proportional to the development of female flowers. In other words, the higher the temperature, the more male flowers and the less female flowers appear. When the temperature is low, it is beneficial to the development of female flowers, and the position of the first female flower is low. Especially night temperature plays a decisive role in sex differentiation of watermelon. Low night temperature is beneficial to the development of female flowers, high night temperature is beneficial to the development of male flowers, and high temperature day and night can reduce and delay the occurrence of female flowers. When the daytime temperature is 20℃ and the nighttime temperature is 13℃, the node position of the first female flower is generally 9- 10, and then a female flower appears every 4-5 nodes. If the temperature is 27℃ during the day and 22℃ at night, the node position of the first female flower will be extended to 20 nodes. Female flowers are 6-7 nodes apart. The suitable temperature is 20-22℃ during the day and 13- 15℃ at night.

Light has little effect on flower bud differentiation of watermelon, but short sunshine is beneficial to the development of female flowers and long sunshine is beneficial to the development of male flowers.

2. Effect of humidity on germination and differentiation of watermelon seeds.

Air humidity and soil humidity have certain effects on the germination, differentiation and flowering of watermelon. When the air humidity is high, the germination and differentiation form early, which is beneficial to the formation of male flowers. When the soil moisture is too high, the root pressure increases and the cell protoplasm colloid expands excessively, which leads to the strengthening of respiratory oxidation process, which is not conducive to flower bud differentiation and female flower formation. Only suitable air humidity and soil moisture are beneficial to flower bud differentiation and female flower formation. The suitable field humidity is 60%.

3. Effects of hormone drugs on seed germination and differentiation.

Hormones can affect the biochemical changes in plants, thus directly affecting the flower bud differentiation of watermelon. Spraying gibberellin 30- 100mg/L on watermelon leaves or growing points can promote the development of male flowers and inhibit the occurrence of female flowers. Ethylene hormone is a hormone with strong growth rationality. Once absorbed by crops, it can inhibit the development of male flowers, female flowers and main vines. Therefore, foliar fertilizer containing hormones should not be used at the initial stage of fruit setting.

4. Effect of variety characteristics on germination and differentiation of watermelon.

Generally speaking, European and American ecotypes have strong growth potential, high fruit-setting festival and weak growth potential in Europe and Asia. In the case of too much rain and high soil moisture, European and American varieties are more obvious in the field. The author thinks that pure northern varieties are a little unsuitable for planting in the south. Therefore, melon farmers should be especially careful when purchasing seeds, try to use varieties approved or recognized by the province and introduce a large number of cultivation. It must be tested before promotion.

Watermelon in the open field is usually transplanted from the end of April to the beginning of May, and the middle and late May is the key period for watermelon flower bud differentiation and flower organ formation. According to the observation of meteorological department, the average temperature in Shaoyang in mid-May this year was 20.78℃, the highest was 23.53℃, the lowest was 18.75℃, the highest was 26.5℃, and the average temperature in late May was 23.865,438+0℃, the highest was 28.30℃, and the lowest was 20.465,438+0℃. Compared with previous years, there was 6-76% more rain, especially on May 5, 6, 13, 14, 15, 20, 2 1 day, 25 and 26, with high temperature during the day and high temperature at night. Therefore, you can't blame the variety show for any problems. Melon farmers can only find the answer from the analysis of your watermelon growth, the weather at that time and field management.

Secondly, watermelon seedlings grow too fast and poor pollination is also the main reason that affects watermelon fruit setting.

1. Excessive application of nitrogen fertilizer in the field can easily lead to white growth of melon seedlings, physiological disorder and excessive vegetative growth, which is manifested by elongation of stems and vines, hypertrophy of leaves and erect vine tips. Female flowers are small and few.

2, continuous rainfall, unable to pollinate, resulting in long white melon seedlings.

3, pests and diseases will also make watermelon unable to bear fruit.

In the production process, anthracnose and epidemic disease seriously harm the leaves, stems and vines of watermelon, causing the leaves to dry up and die, and in serious cases, it is like fire. Pieris rapae not only eats leaves but also flowers. Like this, watermelon is difficult to hold.

4. Poor pollination. Watermelon is a cross-pollinated crop, mainly pollinated by insects. In the case of little insect activity, artificial pollination must be carried out, but the time and quality of pollination must be mastered. Especially when the temperature is low, pay attention to whether there is pollen on the male flowers. Pollination time should not be too long, otherwise it is difficult to bear melons.

Three. Main technical measures taken

Generally speaking, the fruit-setting nodes of large-fruit watermelon varieties should be within 30 nodes of the main vine, the middle-fruit watermelon varieties should be within 25 nodes of the main vine, and the small-fruit watermelon varieties should be within 20 nodes of the main vine. If you exceed this node, it means that there is something wrong with your watermelon seedlings, and you must take corresponding measures to reduce losses.

1, depending on the vine potential to continue pollination. For example, the distance between the open node of female flower and the top of vine is 70 cm, which indicates that melon can continue to pollinate and grow. On the contrary, watermelons are difficult to survive or have deformed melons. If the planting density is sparse, the vines are not crowded and the leaves do not overlap, the fruit-setting festival can be extended and pollination can continue.

2. After cutting the vines, stay in the sun and continue to grow vines. For melon seedlings with high planting density and particularly long vines (more than 30 knots), the method of cutting vines to shade the sun must be adopted to let them continue to bear melons. The specific method is: cut off the original stems and vines 30 cm away from the stump, leave two thick vines after 5-7 days, apply the quick-acting fertilizer once, and apply the medicine once in an all-round way. Promote the stable growth of melon seedlings. When female flowers appear, artificial pollination is carried out. This method may be about 20 days later than before. The vines must be pruned on sunny days, and the stems and leaves should be taken out of Gua Tian in time.

3. Pest control. The main diseases are anthracnose and leaf blight. Pesticides such as mancozeb and chlorhexidine can be used for prevention and control after rain. Pests are mainly cabbage worms, aphids and so on. It can be controlled by cabbage caterpillar green and aphid lice net. In the prevention and control of pests and diseases, we must pay attention to the following points: First, strictly follow the proportion in the drug instructions and use them together; Second, use medicine at 4-5 pm on sunny days to avoid burning seedlings at high temperature; Third, when spraying, spray both sides of the leaves; Fourth, it should not be mixed with other pesticides.

4, timely and appropriate topdressing and hydrating to promote watermelon expansion. When the young watermelon fruit has a big cup, it needs big water and fertilizer at this time. If the weather is dry and the base fertilizer is insufficient, it is necessary to replenish water and fertilizer in time. Generally, the leaves are drenched with 0.5% compound fertilizer water, and foliar fertilizer can be applied again when the leaves return to Huang Shi.

Management of pollination and fruiting period of seedless watermelon

Allocate suitable pollinating varieties: the ratio is 10: 1, that is, plant 10 seedless watermelon and 1 common seedless watermelon.

Selection of pollinated varieties: Watermelons with sufficient pollen and completely different fruit types or skin colors are selected from seedless watermelons for identification.

Pollination node: Pollination begins when the second female flower of seedless watermelon main vine opens.

Pollination: When the female flower of seedless watermelon is fully open on that day (usually around 6: 30 in sunny days and around 7: 00 in cloudy days), take the male flower of common seedless watermelon, invert the male flower to expose the stamens, and sprinkle the pollen gently and evenly on the three stigmas of the female flower, paying attention to the fact that your hands can't touch the ovary and villi of the female flower. Generally, a male flower produces 1-2 female flowers, which pollinates the whole flower. In rainy days, the female flowers are covered with finger paper caps before opening, the male flowers are picked and covered after pollination, which can improve the fruit setting rate.

Swelling melon fertilizer: When the fruit is stable and the egg size is small, about 20 kilograms of ternary compound fertilizer can be applied per mu, and holes can be dug between the vines and leaves of each melon seedling or mixed with water solution for application.

Selecting fruits and keeping melons: When young melons are 0.5- 1kg, choose melons with regular shape and bright color, which are located between the 20th and 25th nodes of the main vine (that is, the 3rd and 4th nodes of the main vine), and each plant has 1 fruit. Selecting more fruits in the 3rd node of the main vine can ensure high yield.

Turn over and pad the melon: start to pad the melon and turn it over about 15 days after fruiting, so that the whole fruit can get full sunlight. Straw or hairy grass can be used to cushion melons, and at the same time, ants and scarab pests can be prevented from invading. When the slope is steep, shovel the watermelon into the soil with a bamboo stick to prevent the fruit from sliding down the hillside.

Spraying foliar fertilizer: foliar fertilizer such as 0.2% potassium dihydrogen phosphate can be sprayed in the middle and late stage of fruit development, sunny or cloudy days to improve yield and quality.

Pest control: This period is the peak period of melon seedlings, and mancozeb plus thiophanate-methyl, mancozeb plus carbendazim, mancozeb plus chlorothalonil, chlorfenapyr or bordo solution can be sprayed alternately for control. Generally, spray 1 time every 7 days on sunny days, once every 3-4 days on cloudy days, and then spray in case of rain. If there are many caterpillars, they can be added and controlled at the same time.

4. Picking seedless watermelon:

Identification of watermelon maturity;

1, calculate the number of days of sitting on melons or accumulated temperature.

Generally, it takes about 32-35 days for large seedless watermelon to mature from female flower, and the accumulated temperature is about 1000℃.

2, observe the morphological characteristics:

(1) When the surface pattern of the fruit is clear, the skin is shiny, the pedicel shrinks inward, and the skin in contact with the ground turns from white to yellow (without turning the melon), it is a mature melon.

(2) Most of the epidermis on the fruit stalk falls off and becomes clean, and the base of the fruit stalk shrinks slightly. After picking the melon, those who secrete red-brown mucus at the stalk of the melon are mature melons.

③ Under normal circumstances, the tendrils on melon nodes become mature fruits after drying.

3. Touch the melon surface and listen to the sound:

(1) Cooked melons and raw melons feel smooth when touching the skin.

(2) When you tap or press the melon surface with your fingers, the cooked melon will pop, and the raw melon will pop.

General principle: Seedless watermelons sold locally should be harvested at the ninth maturity, and those shipped abroad can be harvested at the eighth maturity.

References:

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