Watermelon leaves turn yellow, what’s going on? (As shown in the picture)

Cause analysis and treatment methods for yellowing of watermelon leaves:

1. Yellow leaves caused by improper fertilization

Due to the use of unripe human and animal manure, or long-term Extensive use of chemical fertilizers causes excessive fertilizer and burns the roots. Some people use too much low-quality foliar fertilizers. Because many foliar fertilizers on the market contain hormone substances, they cause hormone and micro-fertilizer poisoning in watermelons, causing the leaves to become rigid, chlorotic, brittle, deformed, and yellow.

Prevention and control methods: It is strictly prohibited to use unrotted human and animal manure. Chicken and cow manure must be fully fermented and decomposed in advance before use. When using chemical fertilizers, it is best to use formula fertilization and appropriately increase the application of phosphorus and potassium fertilizers. , when applying base fertilizer, it is not advisable to use too much nitrogen fertilizer to prevent the leaves from turning yellow.

2. Yellow leaves caused by element deficiency?

In recent years, due to the better economic benefits of watermelon planting, the phenomenon of continuous watermelon cropping has become more prominent, which can easily lead to element deficiencies. The more common ones are potassium deficiency, calcium deficiency, and boron deficiency in watermelon, which can easily cause yellow leaves of watermelon to varying degrees.

Prevention and control methods:

1. Try not to crop continuously. ?

2. For continuous cropping of watermelon, while using nitrogen, phosphorus and potassium fertilizers, one bag of Guangxing Dibao can be applied per acre to condition the soil and activate various medium and trace elements solidified in the soil, indirectly To supplement the deficiency of medium and trace elements; for watermelon seedlings that have already developed symptoms of deficiency, spray 800 times of potassium iodine and boron, which has a significant effect on preventing symptoms of watermelon deficiency.

3. Yellow leaves caused by diseases and insect pests

1. Red spider mites; spider mite adults and larvae will concentrate on the back of young leaves to suck the leaf juice, especially those that have not yet expanded. The buds, young leaves and flower buds are the main damaged parts, causing watermelon leaves to be damaged and unable to grow normally. Leaves sucked by red spider mites will turn green and turn yellow, and in severe cases, the leaves may dry up. ?

Control methods: Eradicate weeds around the watermelon field (shed) and cut off the source of the insect. Red spider mites have a short life cycle and strong fecundity, so attention should be paid to early prevention and control. Foliage spray control can be carried out with 1.8% insect mite killer aqueous solution 2000-3000 times or 2% abamectin 1500-2000 times plus potassium iodine boron 800 times.

2. Downy mildew: Watermelon downy mildew is prone to occur during the middle and later stages of the growth of watermelon plants. This disease mainly damages the leaves. Initially, small water-soaked light green spots appear on the leaves, and then gradually turn yellow. The main reason is that the cultivation area is not ventilated and the application of inorganic fertilizers is neglected.

Prevention and control methods:

1. In the early stage of the disease, control watering appropriately, and pay attention to increasing ventilation and reducing air humidity when cultivating in protected areas.

2. Cultivate disease-free and strong seedlings, apply more organic base fertilizers, and pay attention to the reasonable combination of nitrogen, phosphorus, and potassium fertilizers.

3. Completely remove fallen leaves from diseased plants after harvest.

4. Insufficient light causes leaf yellowing

If the planting is too dense, the ventilation and light transmission are poor, or the protected area is poorly ventilated, watermelons are planted in low-lying areas with poor growth, which will also cause Watermelon leaves turn yellow.

Prevention and control methods: Under the condition of ensuring the temperature of the seedlings, try to open windows to ventilate them and reduce ammonia in the shed.

5. Yellow leaves caused by excessive watering

The watering method of watermelon is different from other plants, but some farmers do not know how to water it once a day. Over time, the soil will be too wet and cause Severe leaf yellowing may cause root rot. After watermelon enters the flowering and fruiting stage, it is more sensitive to water. If the water supply is insufficient during this period, the female flower ovary will be smaller and stunted;

Prevention and treatment methods: Water the watermelon reasonably according to the water demand characteristics of the watermelon. It is the guarantee of early maturity and high yield of watermelon. Watermelon requires less water in the seedling stage, and measures are generally taken to control water and squat the seedlings to promote root penetration and strength. During the spreading period, watermelon water management should follow the principle of combining "promotion and control" to keep the soil dry and wet. After the watermelon enters the flowering and fruiting stage. Therefore, it is advisable to keep the soil moist during this period. The watermelon expansion period is a period when more water is needed, and the amount of watering should be increased to keep the soil moist.

DJ Watermelon

Key points of watermelon care:

1. In order to achieve high yield, high quality and efficiency in watermelon production, the "three checks" must be strictly controlled. Master the "Eight Measures", referred to as the "Three Eight Classics of Planting Melons". The "three passes" are the seedling growth pass, the melon sitting pass, and the mid- and late-stage management pass. The "eight measures" are fine varieties, cultivating strong seedlings, plant adjustment, artificial pollination, selection of embryos to retain melons, application of fertilizer and water, prevention and control of diseases and insect pests, and timely harvesting.

2. Watermelon grows and develops very quickly, so cultivation management must be timely and meticulous. For watermelon fields, sandy soil and sandy loam soil should be selected, which can be irrigated in droughts and drained in floods, and have sufficient sunlight. Watermelon cannot be continuously cropped. It should be rotated for 3-5 years in general paddy fields and 5-8 years in dry soil. If continuous cropping is required, grafting must be carried out. Before planting, drainage ditches must be opened until the ground dries out after rain. It is best to open the compartments in a north-south direction to facilitate the melons to spread and grow in the wind, facilitate the expansion of the vines, and prevent the wind from blowing over the melon vines.

Expansion of knowledge about watermelon

1. Medicinal value

The theory of traditional Chinese medicine in my country believes that watermelon is sweet in taste and cold in nature, and has the functions of relieving summer heat, clearing away heat, promoting body fluids and relieving pain. Thirst, diuretic and other functions. For patients with "Bitter Summer Syndrome" who suffer from loss of appetite and weight loss due to the scorching heat of midsummer, eating an appropriate amount of watermelon can stimulate their appetite, aid digestion, promote metabolism, and nourish the body.

2. Nutritional value

Modern medicine shows that watermelon contains a large amount of fructose, glucose, sucrase, rich fruit acid, amino acids, carotene, vitamin C, and vitamin B1 , vitamin B2, calcium, phosphorus, iron and other minerals, these are indispensable nutrients in the human body.