Occurrence and control of watermelon virus disease

Watermelon virus disease, also known as mosaic disease, is one of the three major diseases that damage watermelon in recent years. Viral disease is divided into mosaic virus and fern leaf virus.
First, the main symptoms of viral diseases Mosaic type: first appeared in the leaves chlorotic spots, and later become systematic mottled mosaic, mainly in the leaves with yellow and green spots, leaf uneven, leaves become smaller , Malformation, new leaf deformity, leaflets short, top slightly upturned. The top of the plant is shortened between the internodes and the plant is dwarfed. The result is small and small. There are faded green mottle on the fruit surface.
Fern leaf type: The new leaves are long and narrow, shrink and twist, flowers are not developed, or they are stunted, and it is difficult to set fruit, even if the result is abnormal. The victimization of the fruit became smaller and deformed, causing premature death of the plant in the field and even death. The diseased fruit had dark green and mottled spots on the surface, and there were protuberances, dark melons, cooked soup, and odor of corruption.
Second, the pathogenic factors of watermelon virus disease
1. The selected watermelon varieties have poor stress resistance, especially poor resistance to virus disease.
2. Sufficient bacteria source. The disease is mainly transmitted by insects such as planthoppers, aphids, and leafhoppers. In recent years, with the changes in agricultural ecological conditions and farming systems, more and more weeds are growing in the ground, in the trenches, between trees, and in the fields, providing beneficial sites for insects to transmit viruses, and accumulating a large number of bacterial sources. The viral source of viral disease.
3. Climate factors. The weather is dry and hot, the soil is dry, and sunlight is strong. Virus disease is rapidly transmitted through contact with a large number of media locusts and other sap-sucking insects. In particular, a large number of locusts after wheat yellow are transferred to melon fields. If the control is not timely, it will result in watermelon field virus disease. Outbreaks.
4. Extensive field management. Poor land, lack of fertilizers, extensive management, weak growth,
Water-deprived plots are prone to this disease. In addition, the field operation is extensive, and the virus is transmitted from the diseased plant to the healthy plant, and the virus invades from the wound. Aphids are natural mediators of the disease, so the delay in treating a wart will accelerate the spread of the disease.
Third, prevention and control measures
1. Use resistant varieties. Selected varieties with strong antiviral disease were soaked in 150-fold formaldehyde solution for 20 minutes before sowing or soaked in 10% trisodium phosphate for 10 minutes to disinfect the seeds.
2. Strengthen field management. The first is the timely removal of fields, land and surrounding weeds. The second is to increase organic fertilizer and phosphorus and potassium fertilizers to increase plant resistance to disease. Third, timely watering to prevent drought, before the onset of the hot season in summer, the plant growth must reach the level of ridges, so that strong light can not direct the ridge between the ground, so as to avoid wilting plants at noon, but also interplanting corn to reduce light intensity. Fourth, when farming operations, we must be careful to reduce human wounds, so as not to provide access to the virus. Fifth, in the seedling stage, silver-gray membranes are used in the fields to avoid embarrassment and reduce the migration of locusts.
3. Elimination of poisonous insects. Before the wheat harvest, the following methods were sprayed to prevent the transmission of toxic insects such as planthoppers, leafhoppers and aphids.
(1) Spray with 2.0% avermectin 7000-fold plus 20% acetamiprid 300-fold.
(2) spraying 40% dimethoate EC 1000 times, can also be sprayed with 25% deltamethrin EC, 20% extinction killing 3,000 times EC, 10% imidacloprid wettable powder 2000 times spray control.
4. Prevention of viral diseases. At the beginning of onset, spraying 20% ​​virus A300-500 times or 1.5% phytosanitary 500-800 times, and adding 1000 times potassium permanganate solution plus 800 times solution of galidophos or 200 times milk powder is more effective. Spray about 2-3 times every 7 days or so.

Leather

Sensory Cortex,Occipital Cortex,The Frontal Cortex,Periamygdaloid Cortex

Henan Qiancuntang medicial technology co.ltd. , https://www.qctchineseherb.com