Introduction to the causes and control measures of virus disease in watermelon

Watermelon is one of the most popular fruits in summer, it tastes sweet and delicious, and has the effects of heat-clearing and detoxification, diuresis and so on. Watermelons are grown in many parts of our country, and now they can be eaten all the year round. In the process of growing watermelon, it is easy to be harmed by virus disease. Let's take a look at the causes and prevention measures of virus disease in watermelon.

I. the causes of virus disease in watermelons

Watermelon virus disease is mainly caused by melon mosaic virus and cucumber mosaic virus. The virus overwintered in infected aphids, seed epidermis and some persistent root weeds and became the source of initial infection in the coming year. Aphids, planthoppers, thrips, jumping beetles, whitefly and other poisonous insects as well as contact and transmission in agricultural activities are the main ways of spread of the disease.

2. Types of watermelon virus disease

Watermelon virus disease is generally divided into mosaic type and fern leaf type, no matter which kind, the threat to growers is relatively great.

At the initial stage of mosaic virus disease, the top leaves appeared yellow-green mosaic pattern, then became wrinkled, the leaves became smaller, the leaf surface was uneven, the internodes of new stems were shortened, slender and twisted, and little or no fruit was set.

Fern leaf virus disease newborn leaves become narrow, wrinkled and twisted, slow growth, plant dwarfing, sometimes showing clusters at the top is not long, floral organ development is poor, serious can not set fruit. The diseased plants with late onset of disease have poor fruit development and form deformed melons, and some fruits have uneven surface, small fruit and dark brown flesh, which have a great impact on yield and quality.

III. Prevention and control measures of watermelon virus disease

1. Applying sufficient base fertilizer: according to the ratio of nitrogen, phosphorus and potassium required for watermelon growth, 2.83 / 1VR 3.4, formula fertilization was applied, and a certain amount of fully mature organic fertilizer was applied as far as possible to improve the disease resistance of the plant.

2. Seed treatment: soak the seeds in 70 ℃ warm water for 10 minutes before sowing, or soak the seeds in 10% trisodium phosphate solution for 20 minutes, rinse with clean water and accelerate germination and sowing.

3. After emergence, the 500-fold EC or 2.5% bifenthrin EC which has a certain effect on aphids, thrips, whitefly and other virus-transmitting insects are sprayed in time.

4. At the initial stage of the disease, foliar spraying of 22% dimethylene copper sulfate wettable powder 16 grams + 33% morpholine guanidine water agent 20 ml + 0.9% aphid lice EC 30 ml + 0.01% brassinolide soluble solution 1 ml, or 22% alkenyl copper sulfate wettable powder 16 grams + 58.8% paracetamol dextrin hydroxyl wettable powder 20 grams + 2.5% bifenthrin EC 30 ml, mixed with 15 kg water.

5. Strengthen the cultivation management and increase the application of phosphorus and potassium fertilizer. Pay attention to drought prevention, timely and appropriate watering, promote plant development and enhance disease resistance. In time to carry out field pruning, forking, heart-picking, vine-binding and other agricultural operations, diseased plants should be separated from healthy plants to avoid human infection, and weeds should be thoroughly eradicated to prevent insect transmission.