Control methods of Yellow Leaf Disease of Watermelon

Watermelon yellow leaf disease can be treated by washing with clean water, controlling the amount of fertilizer, selecting high quality organic fertilizer and so on. For different causes of yellow leaf disease, the required methods are also different. Yellow leaf disease caused by excessive use of pesticides can be alleviated by rinsing with clean water to rinse the chemicals that remain on the surface. Yellow leaf disease caused by excessive nitrogen fertilizer needs to be reasonably controlled and high quality organic fertilizer should be selected for application.

Planting techniques of watermelon

1. Select the place

Watermelons can be planted in places where the soil is deep and easy to drain, and sandy loam is the most suitable. The cultivation of melon crops in dry land within 5 years and paddy field within 3 years.

2. Soil preparation and fertilization

After the completion of the soil preparation work, base fertilizer and organic fertilizer should be applied to make the bottom, to replenish the soil nutrition, inorganic fertilizer can be added in an appropriate amount. The combination of nitrogen, phosphorus and potassium fertilizer should be reasonable, and the amount of fertilizer application depends on soil fertility and cultivated varieties. Small fruit watermelons and grafted watermelons can be 20% less fertilizer, using high border planting, wide border 4-4.5 meters, narrow border 2.0-2.5 meters.

3. Colonization

The seedling age of precocious watermelon is about 1 month and can be planted with 2-3 true leaves. The seedling age of medium-maturing watermelon is 20-25 days, and that of late-ripening watermelon is 7-10 days.

4. Pruning and pressing vine

The method of three-vine pruning is generally used. In the 8-9 leaves of the main vine, leave the main vine and two strong lateral vines, and remove the rest of the son vine and grandson vine. Pruning should not be carried out in overcast and rainy days to prevent the spread of diseases. When the vine grows to about 50 cm, press the vine with soil combined with pruning, then press it again at intervals of 3-4 nodes, and press each vine for 2-3 times to evenly arrange the melon vine. [19]

5. Sitting melon

The 2nd and 3rd female flowers on the main vine or the 1st and 2nd female flowers on the lateral vine should be selected. Melon sitting should be carried out in low temperature weather as far as possible, which can ensure the melon sitting rate.

6. Topdressing

When the young melon grows to the size of an egg, the expanded melon fertilizer is applied according to the plant growth, generally applying 45% nitro-sulfur or potassium sulfate type controlled-release fertilizer 15-20 kg every 667 square meters.

7. Moisture

The seedling stage should be watered as little as possible, and then start watering appropriately according to the situation after slowly growing up. The fruit should not be watered 7-10 days before harvest, so that the fruit can accumulate sugar. Drain the stagnant water in the field immediately after irrigation and rain, otherwise it is easy to cause rotten roots and vines.