In recent years, Tomato yellow leaf curl virus disease has become the most serious disease in tomato production in autumn and winter. In 2009, the disease took place in the greenhouse in different parts of our province. Bemisia tabaci is the main vector of the virus, and the main way to prevent disease is to prevent the invasion of Bemisia tabaci. At present, the greenhouse overwintering tomato in the solar greenhouse is about to enter the nursery period. In order to do a good job of prevention and treatment of the disease, we hereby make the following observations:
First, follow the "prevention-based, comprehensive prevention and control" plant protection policy, according to local conditions to take "avoid, block, induce, kill" and other prevention and control measures.
Second, to cultivate disease-free pest-free seedlings
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. During the nursery period, nursery sheds with 40 or more meshes are used to cover the nursery sheds for isolation and nursery. The shed with the top membrane can be enclosed with insect nets on the skirts to ensure the coverage is tight; yellow leaf boards are suspended immediately after the emergence of true leaves. A square meter seedling is hung on a sheet. When it is found that the amount of yellow board baiting to kill the whitefly is 2~3 or more, pesticides shall be sprayed in time to kill the whitefly and may be controlled by imidacloprid or buprofezin. The seedling stage needs spraying. ~2 times.
Third, management after planting
Before the colonization of tomatoes, the residues and weeds in the shed shall be removed, and an insect net shall be covered at 40 mesh or more at the vent of the greenhouse to control the foreign insects. After planting, the yellow armyworm board was hung in the greenhouse to alert and seduce Bemisia tabaci. 20 to 30 yellow plates were placed per acre of greenhouses, placed between rows, and the hanging height was 20 cm higher than the top of the plants.
In the early stage of growth, the diseased plants should be removed in time to reduce the source of poisons; the management of fertilizers and water should be strengthened to increase the disease resistance of the plants; the older nymphs of B. tabaci are mostly distributed in the lower leaves. The appropriate removal of old leaves can effectively control B. tabaci.
Bemisia tabaci has mobility in the field, and chemical control of Bemisia tabaci must master four key technologies: First, treatment is early and small, early control of B. tabaci population density is low, and the age of the worm is relatively small. The age of Bemisia tabaci adult nymphs is thin, can not be crawled, there are many opportunities for exposure to pesticides, poor drug resistance, and easy to control; second, centralized and unified use of drugs, tobacco powder foraging, miscellaneous host, migration, liquidity, Only the whole ecological environment, especially the weeds outside the field, can be used to control the reproductive hazards; the third is the full time of drug control in key periods. B. tabaci breeding rate is high, life cycle is short, the number of groups is large, the generation overlaps severely, eggs, nymphs, adults of a variety of long-term coexist, in the July-September period of B. tabaci breeding peak period must be full drug control Control the proliferation of harm; Fourth, select the quasi-drug, alternating use. The agents that have better control effect on whiteflies include imidacloprid, avermectin, butylthioimidacloprid, buprofezin, fipronil, and the like, and different medicaments are alternately used to delay the development of resistance.
When the field shows symptoms of tomato leaf curl virus disease, virus inhibitors can be sprayed at the early stage of the disease to enhance fertilizer and water management, promote robust growth of plants, and reduce the incidence of losses. Virus inhibitors may be selected from the group consisting of Gram-negative grams, phytopathogenic spirits or morpholinium ketide.
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