For various reasons, the bitter gourd leaves are often yellow when planting bitter gourd. Then, what is the reason for the yellowing of bitter gourd leaves? What about the yellowing of bitter gourd leaves?
What is the cause of bitter gourd leaf yellowing?
The first is the bitter gourd leaf yellow caused by lack of fertilizer. When bitter gourd is deficient in nitrogen, the leaves are small and the upper leaves are smaller. It gradually turns yellow from the bottom to the top, and the internodes near the growth point are obviously shortened. The veins are yellowed, the veins are prominent, and then spread to the whole leaf. There are few fruit sets, the swelling is slow, and the fruit is deformed. In this regard, appropriate amount of topdressing should be carried out in due course, in accordance with the principle of light, medium and heavy. Before the flowering result, the plant growth is small, and the topdressing should be less; after flowering and fruit setting, the amount of fertilizer and water is gradually increased. As a result, the plant growth and the melon are carried out at the same time, and the topdressing should be applied again. At the end of the results, the plants began to age, and appropriate topdressing should be applied to prevent premature senescence of the plants and affect fruit growth.
Followed by the accumulation of water to cause leaf yellow. The root system of bitter gourd is relatively developed, with secondary roots as the main source and weak regenerative capacity. Therefore, bitter gourd is not wet. The growth period requires about 85% of the relative humidity of the air and the relative humidity of the soil. It is not suitable for water accumulation. The accumulated water tends to cause necrosis of the roots, roots and leaves. In this regard, each time after watering, the water should be prevented from accumulating for a long time in the field, that is, the irrigation should be discharged, especially after the rain, it is necessary to pay attention to clearing the ditch and draining water in time to prevent water accumulation in the field.
Another is the natural aging leaf yellow. The bitter gourd is strong in branching, and the lower leaves are naturally yellowing and aging due to the lack of nutrient supply. Therefore, it is necessary to pruning bitter gourd. When tying the vine, remove the side vines of the main vine below 50cm, and choose to leave 1-2 healthy side vines above, let them grow, and remove the other side vines in time. In the middle and late stages, the senescent yellow leaves in the lower middle part of the plant and the weak or fruitless side branches in the upper part should be removed early.
How to do bitter melon leaves yellowing
The root system of the water-sucking yellow leaf bitter gourd is relatively developed, but the secondary side root is the main one, and the regeneration ability is weak, so the bitter gourd is wet and not resistant to cockroaches. During the growth period, about 85% of the relative humidity of the air and the relative humidity of the soil are needed, but it is not suitable for water accumulation. The accumulation of water tends to cause necrosis of the roots, and the leaves are yellow-scarred, which affects the results, and the disease is caused by death.
After each watering, it should be prevented from accumulating water for a long time in the field, that is, the irrigation should be discharged, especially after the rain, it is necessary to pay attention to clearing the ditch and draining water in time to prevent water accumulation in the field.
In the absence of nitrogen, the leaves are small, the upper leaves are smaller, and gradually turn yellow from bottom to top. The internodes near the growth point are obviously shortened, the veins are yellowed, the veins are prominent, and then spread to the whole leaf. Less fruit, slower swelling, fruit deformity.
For the lack of fat yellow leaves, we should do a good job of bitter gourd top dressing, in accordance with the principle of light, medium-term and late-stage supplements in the early stage. Before the flowering result, the plant growth is small, and the topdressing should be less; after flowering and fruit setting, the amount of fertilizer and water is gradually increased. As a result, the plant growth and the melon are carried out at the same time, and the topdressing should be applied again; in the later stage, the plant begins to age and should be properly topdressed. To prevent premature aging of plants and affect fruit growth. After flowering and fruit setting, the fertilizer should be applied, and 15 kg of urea per acre and 10 kg of potassium sulfate. After harvesting the first batch of melon, each time we apply about 10 kg of urea. In addition, on sunny days and evenings, spraying 0.2% urea and 0.3% potassium dihydrogen phosphate aqueous solution on the foliage can promote the growth of stems and leaves, prolong the harvest period, and avoid the yield and quality caused by premature senescence of plants.
The natural aging yellow leaf bitter gourd has strong branching and leafy foliage, and the lower leaves naturally turn yellow and senescence due to the lack of nutrient supply.
Bitter melon is mainly composed of main vines, so it needs to be pruned. When tying the vine, remove the side vines of the main vine below 50 cm, and choose to leave 1-2 healthy side vines above, let them grow, and remove the remaining side vines in time. In the middle and late stages, the senescent yellow leaves in the lower middle part of the plant and the weak or fruitless side branches in the upper part should be removed early.
The yellow leaf of anthracnose mainly occurs in the middle and late growth stages of bitter gourd, and it is easy to occur under low temperature and rainy conditions from July to August. The onset of the leaves generally begins to develop from the roots of the old leaves. The lesions are water-stained round yellowish spots at the beginning, and then enlarged into brown round spots with a diameter of 0.1-0.5 cm. There is a purple halo around the periphery, sometimes concentric rings appear. It is easy to be broken when dry. In severe cases, the lesions are synthesized with large plaques, and the leaves are dry and dead. When the humidity is high, the leaf surface lesions produce light gray to reddish brown sticky material.
70% thiophanate-methyl WP 500 times solution, or 80% anthrax defame WP 800 times solution, 50% thiram double WP 500-600 times solution, 25% azoxystrobin suspension 1500 times Liquid, 68.75% oxaconazole·manganese zinc water dispersible granule 1000 times solution, 60% pyraclostrobin water dispersible granule 500 times solution, 50% ether oxystrobin dry suspension agent 3000 times solution, 56% azoxystrobin Ester chlorothalonil suspension 800 times solution, 10% difenoconazole water dispersible granules 1500 times solution, 30% benzyl propionazole emulsifiable concentrate 3000 times solution, 20% fluorosilazole · prochloraz aqueous emulsion 55-66 ml / mu, 40% more · Fu · bromine bacteria wettable powder 400-600 times liquid, 50% prochloraz WP 1000-2000 times liquid spray control, 6-7 days spray once, even spray 3-4 times.
The yellow leaves of root-knot nematode showed poor growth, short stature, yellowing, wilting and necrosis of the leaves from the bottom, no ribs or tumors on the surface of the melons, or some no ribs or tumors, and the plants gradually wilted and died. However, the disease is mainly caused by the roots of bitter gourd. The lateral roots and fibrous roots of the damaged plants are more than normal plants, and the roots are formed into spherical or irregular tumors. The nodules are initially white, soft in texture, brown or dark brown in the back, and have a rough surface. A serious strain can be pulled out to see the root for identification. If the yellow leaf caused by root-knot nematode disease is too late, it can be strengthened in the future planting. One is to use 0.2% hypertonic avermectin per acre for 15 days before sowing or transplanting bitter gourd. Powder 4-5 kg, or 10% thiazolyl granules 2.5-3 kg, add 50 kg of fine soil and spread to the surface, deep turn 25 cm, soil disinfection, can achieve the effect of controlling nematodes. Or use 10% sulphur phosphorus granules 3-4 kg per mu, ditch application, or 3% chlorazol granules 4 kg per mu evenly applied to the Dingzhigou. In the early stage of the disease, 1000% of avermectin emulsifiable concentrate 1000-1200 times solution or 50% phoxim emulsifiable concentrate 1000-1500 times solution can be used to irrigate the root. 250-500 ml of each potion solution, once every 7-10 days, a total of 2-3 times.
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