This year, tomato yellow leaf curl virus disease has been endemic and erupted in many areas of our province. However, the growers still lack understanding and preparation for this new type of disease. Once this disease occurs, it often causes serious production cuts and even no harvest. The vegetable farmers have suffered heavy losses. A few days ago, vegetable farmers successively received calls and letters to inquire about how to prevent and treat diseases. Researcher Dai Suying of the Economic Crops Research Institute of Hebei Academy of Agricultural Sciences combined field trials and put forward her prevention and treatment suggestions on this disease, hoping to help the majority of tomato growers.
I. Symptoms of tomato yellow leaf curl virus disease
The disease can occur during the flowering period, fruiting period and harvesting period of tomato. Tomato plants infected with the virus, the initial occurrence of the main manifestations of plant growth retardation or stagnation, internode shortening, plant dwarfing; upper leaves yellow, yellow leaf veins between mesophyll, leaf edge rolled up, leaf folds, leaves become smaller change Thick, hard and hard leaves, with typical symptoms of the upper leaves of the plants, the symptoms of the lower old leaves are not obvious; unable to normal flowering results; late fruiting performance is less, the fruit is smaller, swelling is slow, mature fruit can not be normal color.
Second, the yellow leaf curl disease spread and epidemic conditions
The virus disease is mainly transmitted by whiteflies. After being given the virus, it can be transmitted for life but not transmitted by eggs. The greenhouse tomato cultivation in autumn and winter is due to be between August and October. The occurrence of Bemisia tabaci is serious, and the harm is serious and it is easy to transmit the virus. After December, the spread of diseases slowed down. After the second year of the following year, with the temperature rising, the whiteflies increased, and the disease gradually worsened. The tomato in winter and spring, due to nursery time between 11 to 12 months, Bemisia tabaci has been dormant over winter, does not harm the tomato seedlings, generally to 4 to 6 months before the plants will occur mildly. Premature ripening of tomatoes in greenhouses also occurred mildly from April to June. Late autumn tomatoes are heavier from August to September in the late growth period.
Under the conditions of protected cultivation, Bemisia tabaci can take place on an annual basis. Low density Bemisia tabaci can cause the spread and spread of the virus. The seeds are not poisonous, and the sap of diseased plants cannot be inoculated and infected by artificial friction, but the plants and fruits are poisonous.
Third, the prevention and treatment of tomato yellow leaf curl virus disease measures
1. Cultivating disease-free pest-free seedlings is the key. The earlier the tomato disease infestation of the disease, the higher the incidence rate, so the prevention should be grasped from the nursery period, so that early prevention and early control, and strive to reduce the incidence of disease or not. To remove weeds from the seedbed, clean the seedbed soil to reduce the source of the disease. Soaking with gene activator. Seedlings were transplanted with vegetables and irrigated 3000 times after spraying to prepare soil and covered with 40 to 60 mesh insect nets. Spraying 1 or 2 times of tomato yellow leaf curl virus to prevent seedling.
2. Regain protection against whiteflies. Tomato yellow leaf curl virus disease is transmitted by whiteflies. Bemisia tabaci is afloat, and it is necessary to strengthen unified management of pruning and chemical control in the fields, reduce the migration of whiteflies between adjacent fields, and use a chemical to prevent and treat once-daily tobacco powder every 7 to 10 days. Pharmacists may choose to use imidacloprid, acetamiprid, buprofezin, chlorfenacin, etc. It is also possible to use è™± å® åŠ åŠ plus ä¹ ä¸¹, and pay attention to rotation, or use 蚜虱 冲 净 净.
3. Agricultural measures. Appropriately control the amount of nitrogen fertilizer on the cultivation and keep the field moist. Irrigation with fertilization is done a small number of times, so as to avoid drought or drought, timely release of air, avoiding high temperature in the greenhouse, regulating the temperature and humidity in the field, increasing organic fertilizer, promoting robust plant growth, and improving the disease resistance of the plants. Transplanting irrigated roots or irrigating roots, combined with tomato yellow leaf curl virus spirit, improve plant immunity, timely removal of weeds and debris in the field to reduce the source of insects. Greenhouse vents are isolated with 40 to 60 mesh insect nets, and are used in combination with field yellow plates to prevent Bemisia tabaci.
4. Vaccination. It is the most economical and effective method to inoculate the tomato seedlings with yellow leaf curl virus vaccine.
Yellow leaf curl virus vaccine: Yellow leaf curl virus vaccine is also called yellow leaf curl virus split vaccine. The main components of the product are inoculated with the current epidemic strain of chlorotic leaf curl virus (vaccine virus strain) and prepared by virus culture, viral fluid harvest, virus inactivation, virus purification, virus lysis, and other processes for the prevention of plant yellowing. Leaf curl virus infection.
Scope of application: The vaccine can be used for vaccination of tomato, eggplant, pepper, cucumber, watermelon, melon, tobacco, zucchini, etc. After inoculation with the vaccine, the body can be stimulated to produce anti-yellowing leaf curl virus immunity for the prevention of yellow leaf curl virus disease, and is also effective for mosaic virus, lobular virus, fern leaf virus, streak virus.
5. Irrigation and spraying combined control of tomato yellow leaf curl virus disease. Prevention and cure of Tomato yellow leaf curl virus disease can be combined with the method of transplanting the roots of vegetables and roots of the roots and the spraying of yellow leaf curling virus Linglin surface spray, which can effectively control the occurrence, spread and epidemic of viral diseases.
Irrigation control: Tomato planting when transplanted with vegetables Irrigation root 3000 times solution root irrigation, 1 mu of land with 500 ml of medicine, water 1000 ~ 1500 kg, each strain diluted with 0.5 kg of liquid medicine. Can also be flushed with water, with 1000 ml per mu.
Spray control: Application of valerian leaf curl virus in tomato seedlings, colonization, binding vines, snoring before spraying tomato yellow chlorophylline can prevent infection. Before and after colonization, each spray of tomato yellow leaf curl virus 600 times liquid can enhance tomato disease resistance. In the early stage of disease (5-6 leaf stages), foliar spray was started with 600 times solution of Tomato yellow leaf curl virus and sprayed once every 4 days for 4 to 5 times. Stop using other pesticides, foliar fertilizers, auxin, and prodrug drugs during treatment.
Seedlings from the prevention of 3 to 4 leaves, prevention once a week; colonization back to the seedlings after the drug, no disease prevention 7 to 10 days 1 time, the initial onset of 3 to 4 days 1, spray 3 to 4 times. On the day of general medication, leaf curl occurs, which is a normal phenomenon. It naturally recovers in 1 to 2 days. Generally, it is best to use 3 to 4 days after watering. 1 to 2 doses can control the spread of disease, and 3 to 4 times of initial onset of drug use. Recoverable, there is no therapeutic significance for growth points that have stopped growing. If the disease has to be applied at the same time as the transplanting of the vegetables and roots, the effect is quick and the recovery is good.
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