Watermelon virus disease, also known as mosaic disease, is one of the most important diseases in production. It generally reduces production by 30%, and when it is severe, it reduces production by more than 70%, directly threatening the production of watermelon.
Symptoms in the field are mainly symptoms of mosaic and fern leaves. The mosaic type expresses the systematic mosaic leaves. The young leaves show shades of white and purple. Afterwards, they are shrunken and deformed, the internodes are shortened, and it is difficult to set the melon or melon to be very small. The fern leaf type shows a new leaf shape, narrow and long, young leaves. Shrinking and twisting, the main vines become thicker, the new vines are finely twisted, and the flower growth is not good. It is difficult for the two types of melons to easily form deformed melons or skewed melons. Severely ill strains are necrotic.
The pathogen is mainly caused by watermelon mosaic virus (WMV) and cucumber mosaic virus CMV.
Characteristics of the disease The disease is mainly transmitted by frictional contact with viral juices, and the seed carrier rate is low. It can also be transmitted non-persistently by peach aphid and cotton aphid. High temperature, strong light and drought are the main conditions for the onset. The management of the growth period is extensive, lack of fertilizer or adjacent to the melon crops, or the occurrence of severe high temperatures. In addition, the occurrence of locusts is more severe.
?? Prevention methods
1. Use disease-free seeds or soak seeds with 10% trisodium phosphate for 10 minutes and wash.
2. Apply organic basal fertilizer and increase phosphate fertilizer and potash fertilizer. During the growth period, strengthen management, timely watering, fertilizing, and timely removal of severely diseased plants and pruning vines.
3, focus on nursery, nurturing strong seedlings, timely control of aphids. At the seedling stage, when the symptoms are not seen, spray 2-3 times of bactericidal WP 300 times or 20% venom WP 500 times every 10 days or so.
4. In the initial stage of disease, it is possible to spray 20% virus A WP 500 times, or 1.5% phytosanitary emulsion 1500 times, or antiviral No. 1 300 times, or 83 sensitizers 100 times.
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