Bacterial Blight of Rice
Bacterial blight of rice or rice bacterial blight is a very dangerous disease. Because this is the most destructive disease for rice crops. It is a common fungal disease that is caused by a special type of fungus known as Xanthomonas oryzae. In the event of a severe blight attack, damage to the rice crop is expected to range from 60% to 80%. So the disease affects millions of hectares annually. The blight of rice disease is first reported in Kyushu, Japan. The blight or rice disease attacks are more common in hot weather conditions.
Symptoms of Blight
The blight of rice is characterized by the appearance and spread of yellowish-green water-socked lines on the ends and lines of leaves. Then white and grey dots appear on the leaves. Which indicates an acute onset of the disease. The disease appears within two to three weeks after the transplantation of the paddy. When the onset of this disease, the leaves first wither and then dry.
History of Bacterial Blight of Rice
The bacterial blight of rice is a devastating disease that can affect any rice crop. Millions of acres of rice are affected every year, and in the worst of outbreaks, crop loss can approach 75%. First noticed in 1884–85 in Kyushu, Japan, the disease’s causative agent, the bacteria Xanthomonas oryzae pathovar oryzae (then known as Bacillus oryzae), was discovered in 1911. Bacterial blight is most common in the rice-growing regions of Asia, the western coast of Africa, Australia, Latin America, and the Caribbean due to the region’s warm and humid climate. Although Xoo-related bacteria are uncommon here, the U.S. Department of Agriculture has classified one of them as an agricultural select agent, subjecting it to stringent controls.
Bacterial Blight of Rice is Caused by
Bacterial blight of rice caused by, more likely to spread to areas where pre-infected plants are present or weeds are abundant. Ric Bacterial Blight can occur in both tropical and temperate climates, especially in irrigated and rain-fed low-lying areas. Because blight disease prefers a temperature of 24-35 ° C, with relative humidity exceeding 69%.
Bacterial Blight of Rice Disease Cycle
Bacterial blight is usually seen when there are strong winds and constant heavy rains, due to which the pathogenic bacteria can easily spread through the moisture droplets on the wounds of the infected plants. So the bacterial disease of rice can be spread in rice varieties under the usage of high nitrogen fertilization.
Rice Leaf Blight Control Measures
The efficiency of current methods for preventing rice bacterial blight is low. Safety problems, impracticality, and bacterial resistance have rendered chemical treatment mainly ineffectual in reducing bacterial blight. The use of bacterial antagonists of pathogens (disease-causing organisms) in biological control strategies has shown promise in reducing bacterial blight. Cultivating rice cultivars with genes that provide resistance to Xoo infection is the most popular form of defense against rice bacterial blight. More than 30 resistance genes (Xa1–Xa33) have been found in rice plants, and some of them have been included in the genomes of commercial rice strains. Many countries that rely on rice production have seen substantial improvements in their crop because of these resistant rice types.
Cultural Practices
- Cultivate those varieties that are resistant to diseases.
- Always use nursery disease-free seeds.
- Use the fumigation method before sowing seed.
- Remove weeds in the nursery as well as the field on time.
- Use a drip irrigation system for watering.
- Proper spacing between the plants.
Chemical Control Method
Mixing and dissolving one kilogram of copper sulphate in fifty liters of water and one kilogram of lime powder in another fifty liters of water in plastic buckets, and then slowly adding the copper sulfate solution to the lime solution, a one percent Bordeaux mixture was prepared prior to each spray application. Constant stirring was maintained during the manufacture of solutions, which were concurrently placed into a third container, thoroughly mixed, and sprayed. All investigated substances were sprayed at a 5-day interval till the onset of the sickness. All sprayings were performed by hand, and plants were sprayed at 2000 kPa pressure till runoff.
Approximately 5 to 10 liters of spray mixture was applied per treatment. Evaluation of the incidence of bacterial leaf blight on tagged plants. Bacterial blight of rice disease control for chemically control method, Streptomycin sulfate + Tetracycline combination 300 g + Copper oxychloride 1.25kg spray for Acer repeat 15 days later. If the onset of the disease is in the early stages, it is very beneficial to use bleaching powder of 5 kg per acre during irrigation.