How to Treat Watermelon Seedling Diseases? Detailed Explanation of Prevention and Control Methods

Watermelon is a fruit we often eat in summer. It has many varieties and varying prices, but it is deeply loved by people. On the internet there is even a new term called “melon-eating masses.” Watermelon can clear heat and relieve summer heat, and it tastes sweet and juicy. However, for a watermelon to grow, it must go through sowing in March, pests in April, and care in May before it can grow bright red and ripe in June. In addition, it needs help from the climate, with favorable weather all the way, before it can reach our mouths. So when diseases occur during the watermelon seedling stage, how should they be treated?

1. Disease treatment during the watermelon seedling stage

The main diseases during the watermelon seedling stage include damping-off, Rhizoctonia rot, viral disease, and rust root disease. The specific disease should be determined according to the specific symptoms, and treatment should be carried out accordingly.

The main symptom of watermelon damping-off at the seedling stage is that water-soaked lesions appear on the base of the seedling stem, then the diseased part turns yellow-brown and constricts into a thread-like shape. The disease develops rapidly, and the seedling collapses before the cotyledons have wilted. The main treatment method is to spray with 64% Sandofan wettable powder at 500 times dilution, or spray with 25% Ridomil wettable powder at 800 times dilution when disease occurs after emergence.

The symptom of watermelon Rhizoctonia rot is that oval dark brown lesions appear on the base of the diseased seedling stem. In the early stage, the diseased seedlings wilt during the day and recover in the morning and evening. The diseased part gradually sinks, expands around the stem, and constricts and dries up, and finally the plant dies. The main treatment method is to use Qingku Lizhike at 300 times dilution plus garlic oil 15-20 ml to irrigate the roots of severely diseased plants and plants within a 2--3 m area around the diseased plants in a small area, irrigating twice consecutively with a 1-day interval between the two treatments. Depending on the condition, after the second application, wait 3--5 days and apply once more to consolidate the treatment.

Viral disease is also called mosaic disease. After watermelon is affected, the leaves become smaller, growth is slow, and the plant becomes dwarfed. Flower organ development is poor, and in severe cases it cannot set fruit, or after fruit set development is poor, yield is low and quality is poor, losing commercial value. The treatment method is to spray with 10% imidacloprid wettable powder at 1000 times dilution, or 3% acetamiprid emulsifiable concentrate at 1500 times dilution for control, spraying once every 7 days for 2--3 consecutive sprays.

Watermelon rust root disease is also called root rot disease. In the early stage of onset, the cotyledons droop, and the seedlings grow extremely slowly. The roots first appear yellow-rust colored, and new roots are slow to grow. In severe cases, it causes root rot and seedling death. The main treatment method is to spray or drench in the early stage of onset with 50% thiophanate-methyl (Topsin-M) wettable powder at 500 times dilution, or 50% carbendazim wettable powder at 500 times dilution, 60% Fangmeibao ultra-fine wettable powder at 800 times dilution, or 50% benomyl wettable powder at 1500 times dilution. Stop application 3 days before harvest.

2. Key points for watermelon cultivation

Although watermelon tastes sweet, it has relatively high requirements for climate conditions such as soil moisture during cultivation. When cultivating watermelon, be sure to first investigate whether the local climate meets the conditions for watermelon cultivation. The main key points are as follows:

1. Choose loose, fertile sandy loam soil with convenient drainage and irrigation, and it is best not to rotate with other melons and fruits.

2. Base fertilizer should mainly be high-quality organic fertilizer and cake fertilizer, supplemented by inorganic fertilizer. Chlorine-containing fertilizers must not be applied. The amount of fertilizer depends on soil fertility and the cultivated variety. At the same time, topdressing should also be carried out according to the growth of the watermelon.

3. During the seedling stage, water as little as possible, or even do not water. Control moisture before flowering and fruit setting to prevent excessive vine growth. After fruit setting, ensure sufficient water supply to promote fruit expansion and increase weight.

4. For long-distance transport or storage, harvest when 80% ripe. For same-day sales in nearby suburbs, harvest when 90% ripe. Harvesting is generally carried out in the morning.

The above is some relevant knowledge about watermelon diseases and key cultivation points. When cultivating watermelon, be sure to patrol the field often. When abnormal phenomena in watermelon are found, be sure to promptly confirm the cause so as to treat the disease accordingly.