Why do winter melon leaves have yellow spots? How to treat winter melon yellow leaf disease?

This section is a symptom of the initial greenish yellow spots on the leaves, oblong to irregularly shaped, the later lesions are fused and linked, the lesions are light brown to brown, the old lesions are gray, the edges are brown, the size is millimeters, and sometimes gray hairs are born, that is, the conidia and conidia of the pathogenic bacteria. [1]

This paragraph Control methods (1) Choose disease-free seeds, or sow seeds with more than 2 years of old seeds.

2) The seeds were soaked in 500 times of 50% carbendazim wettable powder for 30 minutes.

3) Implement crop rotation with non-melon vegetables for more than 2 years.

4) At the beginning of the disease, spray 500 600 times of 50% mixed sulfur suspension, or 600 700 times of 50% multi-sulfur suspension, once every 10 days or so, and continue to prevent and control 2 3

1. Gray spot disease.

After being infected with gray spot disease, the leaves of winter melon begin to grow yellow-spotted greenish, and the lesions are irregular. After that, the lesions will gradually connect, and the lesions will turn gray-brown in the later stage, so there will be yellow leaves in the early stage. The prevention and control is mainly the use of chlorothalonil soaking seed disinfection, spraying 50% mixed sulfur suspension 500 times the solution when the disease occurs, generally spraying once a week, to see the effect, you can continue to spray several times.

2. Other reasons.

Stagnant water or malnutrition, soil compaction, and drought affects the root system to absorb water and affect the growth of foliage plants. Sometimes, yellow leaves can also occur when burned by strong light. Therefore, it must be planted on higher ground, which is a breathable and fertilizer-retaining sandy loam soil.

Replenish nutrients regularly, and don't wait for yellow leaves to indicate before starting fertilization. After the rain, the soil should be loosened, and in the drought, it should be watered every day in the evening.

3. Excessive fertilization.

Winter melon has strong absorption capacity, if there is too much fertilizer at one time, the concentration of soil solution is too high, which affects the root absorption, the use of chemical fertilizer is too close, it is easy to burn the roots, and after the root system is damaged, the absorption capacity is weakened, which will lead to insufficient nutrients and yellow leaves. Therefore, it is best to apply more microbial agents as base fertilizer, and use farmhouse fertilizer for top dressing. Or it is a compound fertilizer that is not easy to burn, and it should be watered after fertilization.

4. Nematode hazards.

Underground root-knot nematodes harm a variety of vegetable crops, winter melon will be harmed by nematodes will produce melon small yellow leaves, yellow leaves when there is no powder, mold, and the like may be nematode damage, no infection with germs. The leaves will gradually die after yellowing, but they will not fall. Therefore, it is best to dig up the root system and check the soil for nodules, which is the damage.

Use avermectin 500x to irrigate the roots.

If the leaves of winter melon turn yellow, there are actually many reasons, but the symptoms are also different.

It can be controlled with 10% grassworm cryprid powder and seed dressing. In the growth stage of winter melon seedlings, it can be diluted 3000 times and sprayed 2 3 times, once a week. In addition, pest control is necessary at both the seedling stage and the flowering and fruiting stage of winter melon.

If winter melon yellow leaf disease is found, if the leaves are yellowed from top to bottom, nitrogen fertilizer should be applied; If the edges of the leaves are yellow, apply potassium fertilizer; If the new leaves turn yellow, apply iron fertilizer.

Hello, it is recommended to use methyl frost and methalmine or oxamine plus allicin or octamine acetate or shenazinin root irrigation treatment, two to three times in a row, once every three to four days. Hello, it is recommended to use methyl frost and methalmine or oxamine plus allicin or octamine acetate or shenazinin root irrigation treatment, two to three times in a row, once every three to four days.

Stagnant water or malnutrition.

Hello, I am glad to answer for you, the appearance of yellow spots on the leaves of winter melon, commonly known as "dry leaves", once the disease occurs, the rapid development, so early detection, timely prevention and control is very critical. This disease is more common in the middle and late stages of growth, mainly infesting leaves, and often occurs first in the shed dripping or nest wind, forming a disease center, and then spreading rapidly. I hope my answer is helpful to you

First of all, it is necessary to select disease-resistant varieties, pay attention to maintenance, watering, and fertilization during the growth period.

How to care for winter melon.

1. Temperature: Winter melon is not cold-tolerant, and the maintenance temperature should be controlled at more than five degrees.

2. Watering: Its leaf area is relatively large, it needs more water, generally watering once every other day, and the frequency of watering needs to be reduced when the temperature is very low in winter.

3. Fertilization: Before planting it, you need to apply some basal fertilizer. In addition, it is necessary to top fertilize the fertile leaf water-soluble fertilizer once a month.

4. Light: It is a short-day plant, and the daily light time can be controlled at about five hours.