Occurrence and control of wheat stripe disease
Wheat stripe disease is a viral disease. In recent years due to the warming of the climate and the increase in winter temperatures, especially the changes in the farming system, the overwintering and reproduction of the vector insect Laodelphax striatellus that spreads the virus is extremely beneficial. The wheat stripe virus, which is harmed by rice stripe virus, also has severe stripe disease.
First, the symptoms
Wheat stripe disease generally begins to show symptoms from the end of booting to heading and flowering, and the symptoms are most obvious at heading and flowering stage.
1. Spike symptoms: Spike symptoms are one of the most typical symptoms of the disease. The panicles of the diseased plants were pale yellow after heading, which was significantly lighter than that of normal growing ears. The diseased ears couldn't be normally flowered and firm, or only a small part of the spikelets could lift flowers; most of the diseased spikes were tangled and serious ear deformities. Incidence panicles are smaller than normal panicles. In some strains, S-shaped bends appear between the ears. The length of the ear is smaller than the normal ear.
2. Plant height: The diseased wheat plants became short and internode shortened, which was 10-20 cm shorter than normal wheat plants and averaged about 15 cm shorter.
3, leaf color: diseased leaves in the direction of the veins appear yellow and white and green striped lesions, and rice leaf stripe disease leaf symptoms are very similar, serious, early onset diseased flag leaves and inverted two, three leaves All these symptoms occur. Some lesions do not penetrate the entire leaf, and the second and third leaves are normal. Some diseased leaves and the second and third leaves are still normal, and only the ear is yellowish-white.
4. Infection and virus transmission law: The diseased strains showed two symptoms: whole plant infection and non-whole plant infection. Whole-plant infection symptoms showed symptoms on the main stem as well as on all the tillers and spikes, and this symptom accounted for a large proportion of diseased plants in the field, generally reaching more than 90%. Non-whole strains of infected strains sometimes only appear in the ear of the main stem, while other panicles of the same plant do not develop the disease; or the symptoms of one of the tillers are present, but the leaves, heading, flowering, and grouting of the main stem and other tillers occur. However, the symptoms may be normal. The reason may be that the period of transmission of the virus is short, and it only occurs on the main stem or tiller directly infected with the virus. However, the number (concentration) of virus in the other stem cells of the same strain is low and does not reach the onset. The critical value.
5. Yield traits of diseased plants: Some spikelets of the diseased plant ear could be grouted, but the number of grains per spike and 1000-grain weight decreased significantly. The average number of grains per panicle was 17.2 grains, which was 50% of the normal value; 1000-grain weight decreased by 3-5 grams, which was a decrease of 11.5%. Disease plant production dropped by more than 50%. Plants with early onset can not normally head and gradually die.
Second, prevention and control measures
1. Agricultural control: (1) Select resistant varieties. Planting disease-resistant varieties is the fundamental method to solve the hazards of virus diseases. It has the advantages of labor saving, cost saving, and easy acceptance and control for farmers. (2) Change the sowing method. The main method of wheat sowing is changed from rice-wheat wheat to rotary-cultivation and smashing (sowing) sowing. It can pound and smash the rice piles, thus destroying the overwintering sites of SBPH, worsening the overwintering environment, and lowering the base number of winter residues. In order to reduce the amount of insects and reduce the incidence of field. (3) clean the pastoral. After rice is harvested, the weeds in the fields, roads, and ditches are promptly removed, so that the slough does not have a good place for winter hideaways, and the purpose of suppressing the amount of insects can also be achieved.
2. Chemical control: After the autumn sowing, the prevention and control of the rice piles and the combination of other diseases and insect pests should be carried out in 2-3 times. (1) Pharmaceutical selection. Use 40% dichlorvos per acre 200ml +10% imidacloprid 40g, or 40% Profenofos 80 ml + 25% buprofezin 50 grams, the above formulas are watered 30 kg spray or watered 10 kg spray. (2) Precautions. Try not to use the same pharmaceutical formula used for controlling rice planthoppers, and pay attention to the replacement of pharmaceuticals.
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