Occurrence symptoms and control techniques of rice stripe blight

Stripe leaf blight

Rice stripe blight is a viral disease caused by gray planthopper. The disease has shown an upward trend in our region in recent years. At present, the total occurrence area of the main rice producing areas in our region is nearly 100 mu, and the rate of diseased plants in the field is 2% Murray 10%, and shows the trend of epidemic spread. Rice stripe blight has serious damage and great loss. Generally, the output loss of the diseased field is 20% to 30%, and the serious field will cause no harvest.

Symptoms of the disease

In the early stage of the disease, yellow-green stripes began to appear in the heart leaves, gradually curled downward, the withered plants gradually dwarfed, the leaves lost green and white, and finally the leaves faded and died; at the tillering stage, chlorotic macula appeared at the base of the lower leaf of the heart leaf, and then expanded to form irregular yellow-white stripes, and the old leaves did not show disease. The disease occurred after jointing: the yellow-green stripes appeared in the lower part of the flag leaf, the heart was not withered, and the diseased plant often withered booting or small ear deformities.

II. Routes of transmission and conditions of onset

Rice stripe blight virus is transmitted only by the vector insect gray planthopper, but not by other ways. Once acquired, the insect gray planthopper can carry the virus for life and transmit the virus through eggs. The virus not only infects rice, but also harms more than 50 species of Gramineae plants, such as wheat, barley, oat, corn, millet, millet, sorghum, etc., but except rice, other hosts play little role in the infection cycle. The virus overwintered in the infected gray planthopper and became the main source of primary infection. Nymphs overwintering in barley and wheat fields propagate in the original wheat fields after Eclosion, and then migrate to rice seedlings or Honda to spread poison and reproduce. Rice is susceptible to disease from seedling stage to tillering stage. The incubation period of long leaf age was also longer, and the resistance of the plant gradually increased with the plant resistance. The occurrence of stripe leaf blight is directly related to the number of gray planthopper and the rate of infected insects. The population of gray planthopper is frequently and seriously ill.

III. Prevention and control methods

1. Selecting resistant varieties: selecting resistant varieties is the fundamental means to control the occurrence of rice stripe blight. Among the rice varieties popularized and planted in our region in recent years, Chujing 24 and Chujing 29 are more resistant to disease.

2. Adhere to the rotation system of adjusting stubble, improve soil fertility and improve soil group structure.

3. Increase the application of organic fertilizer, improve soil quality, properly control the amount of chemical fertilizer, and pay attention to the application of phosphorus, potassium and silicon fertilizer, so as to promote the healthy growth of rice and enhance its resistance to diseases.

4. Clear the weeds around the countryside. Weeds are important places for gray planthopper parasitism, so it is necessary to strengthen the eradication of weeds in and around the rice seedling field. Eliminate the living environment of gray planthopper, cut off the parasitic chain and reduce the disease.

5. Chemical control. Chemistry and treatment is one of the important measures to effectively control the number of gray planthopper and prevent virus transmission. It is necessary to adhere to the chemical control strategy of "cutting off the poison chain, controlling insects and controlling diseases". The methods of controlling the seedling field, protecting the field, the early stage and the later stage are adopted to control the breeding quantity of gray planthopper and prevent virus transmission. The medicament can choose 25% pyrazidone suspension 24 g / mu or 40% Fogo water dispersible granule 8 g / mu mixed with 50 kg water spray to control planthopper, so as to achieve the purpose of disease prevention. Occurrence and control techniques of stripe leaf blight