Symptoms The symptoms of the disease change greatly. Infected at the seedling stage, the young leaves turn into a copper-colored roll. After forming many small dark spots, the back of the leaf is purple along the veins. Some growth points die. The stem ends form brown necrotic stripe. The diseased plant grows only half or is completely short. Or wilting like defoliation, early onset of no results. After the fruit is infested, the chlorotic ring spot appears on the fruit, the green fruit is slightly convex, the rouleaux is not obvious, brown necrotic spots appear on the green fruit, and the tumor is prominence, and the fruit is easy to fall off. The mature fruits are obviously affected by the ring pattern, reddish-yellow or red-white, chlorotic spots are evident in the full-color period, severe whole-fruit stagnation, umbilical symptoms are similar to those of umbilical rot, but the epidermis of the disease is brown and necrotic and distinct from the umbilicus Rot.
The host host range is very wide, involving 271 species in 34 families of dicotyledonous and monocotyledonous plants. Important hosts include tomatoes, peppers, peanuts, tobacco and other crops.
Transmission routes The disease is mainly caused by the transmission of virus through thrips. In addition, sap can be inoculated, seeds can also be transmitted, poor field management, agricultural operations, and diseased plants can easily cause the disease. This virus can be wintered through some wild plant species. However, the virus epidemic level mainly depends on the population density. The main insects of the mediator insect thrips are buried in the soil. After the spring soil temperature rises, the insects will migrate to the weeds.
Control methods Agricultural control. 1. Use resistant varieties. 2. Eradicate areas where weeds, wild dahlias and field weeds should be eradicated. 3. Rotate with non-solanum crops for more than 3 years. 4. The tools involved in agricultural operations should be disinfected. Physical control. Blue plates can be used to control thrips. Chemical control. The disease mainly adopts the prevention and control strategy of “cutting off the source of the virus and pest control and disease preventionâ€. The available pharmaceuticals include: avermectin + imidacloprid; maggot worm + avermectin.
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