Rice bacillus is one of the important diseases in the middle and late stages of rice. The severity of the disease and the impact on rice are related to the early onset of the disease.

First, the symptoms: Bacterial blight mainly shows symptoms on the leaves, with leaf edge type and withered type. The leaf edge type is common in the late tillering stage to the booting stage. The pathogens invade from the water hole. The disease spots start to appear yellow or dark green short streaks from the tip or leaf edge, and expand along the veins. Sometimes it is corrugated, and the leaves turn gray or yellow and die. The lesions of indica rice are yellowish brown and grayish white. When the humidity in the field is high, the diseased part has a pale yellow dew-like pus, which is small in shape after drying. The wilting type generally occurs about one month after the transplanting of the seedlings. The diseased leaves are quickly dehydrated and smear in the 1-2 leaves under the heart leaves, and then withered, which is like the dying of the mites, and the other leaves are successively wilting. The main sputum and tiller of the diseased plant can be ill and die, causing a large number of dead seedlings and missing clumps in the paddy fields.

Second, the pathogen: the pathogen is a species of the genus Xanthomonas, the bacteria are short, rod-shaped, both ends are obtuse, and one end of the bacteria body has 1-2 linear flagella. The growth temperature of the bacteria is 10 degrees Celsius, 40 degrees Celsius, suitable temperature 26-28 degrees Celsius, and the bacteria are aerobic bacteria. The bacteria are sensitive to heat, the lethal temperature is 53 degrees Celsius, 10 minutes (wet state), and the lethal temperature is 57 degrees Celsius for 10 minutes under dry and gelatinous protection. The survival of pathogens is closely related to environmental conditions. The collected strains are determined on a set of identified varieties, and their pathogenicity is strong and weak, and can be roughly divided into four groups of strains. Group I is weak, Group II is moderate, and Groups III and IV are strong and strong.

Third, the occurrence characteristics: Bacterial blight mainly overwinter on seeds and straw. The source of the first infestation, the new ward is dominated by diseased cereals, and the old district is dominated by diseased grasses. After the seeded rice seeds are sown, the pathogens are invaded by the buds and roots. When transplanting and transplanting, it causes a lot of wounds, which is conducive to the invasion of germs. In addition, the use of diseased straw germination or sputum to block the water hole is also a way for pathogen infection. Irrigation water and storms are important vehicles for the spread of disease. Its occurrence, popularity and climate, fertilizer management, varieties and so on are closely related.

Fourth, prevention and treatment methods

Under the premise of controlling the source of bacteria, based on planting disease-resistant varieties, the key to prevention and control of seedlings is combined with the management of fertilizer and water, supplemented by chemical control.

(1) Strengthening plant quarantine In the disease-free area, the quarantine system should be strictly observed. If it is not introduced from the ward, it is necessary to use coated seeds when it is introduced. It can also be used to treat seeds with strong chlorin, leaf cumin and other agents to prevent the introduction of pathogens. .

(2) Agricultural control

1. Choose resistant varieties.

2. Strengthen the management of fertilizer and water. Putian does not apply unfertilized farmyard manure, Datian should apply enough base fertilizer, early topdressing, skillful application of panicle fertilizer, no application of nitrogen fertilizer, balanced application of nitrogen, phosphorus, potassium and micro-fertilizer. Cultivate high-quality and strong scorpion, prevent flooding of seedlings from flooding, avoid string irrigation, flood irrigation, deep irrigation, prevent diseased water from flowing into disease-free fields, and timely drain the rice fields that are easy to flood. Daejeon should be shallow water, dry, wet and dry, alternating wet and dry, and moderately bake the field.

(3) Chemical control

Spraying in the old ward is the key to the field, usually in the three-leaf stage and before the sputum.

Datian application of medicine should be done with "one point to cure a piece, one piece to cure one piece", and timely spray to block the onset of the disease center. If meteorological conditions are conducive to the onset of disease, similar field censuses should be implemented to control the spread of the disease. Available in 20% leaf cumin WP 1.25-150 g, or Ningnanmycin water 250 ml, or 20% thiabend copper suspension 100-125 ml, 50-60 kg spray, usually 5-7 Apply once a day for 2-3 times.