With sporadic incidence of bacterial leaf blight disease in the standing samba and thaladi paddy crop in a few parts of the district, the Agriculture Department has advised farmers to take up appropriate measures to check its spread if symptoms appear in their fields.
Samba and thaladi paddy crop has been raised on about 49,000 hectares in the district. Due to the intermittent rains during the north-east monsoon and favourable climatic conditions, symptoms of bacterial leaf blight are appearing in the crop in some places. The bacterium enters through the cut wounds in the leaf tips and edges, becomes systemic and causes orange and yellow coloured wavy margins in the leaf tips and edges.
The disease symptoms first appear as small water-soaked translucent lesions on the edges of the leaf blade which later turn yellowish orange or brown, mostly confined to the edges of the leaf with wavy margins. As the disease progresses, the yellowish orange or brown lesions cover the entire leaf blade which may turn straw coloured .This will affect the photosynthesis of the plant, thereby reducing the yield.
For easy diagnosis, the leaf blade of the plant can be cut and dipped in water. If affected, white bacterial ooze could be noticed making the water turbid. Further, the bacterial infestation could lead to secondary infestation of the fungal pathogens which causes fungal diseases in the later stage of the crop.
Clipping of the tip of the seedling at the time of transplanting, heavy rain or dew, flooding, deep irrigation water, severe wind and application of excessive nitrogen, especially late top dressing are some of the favourable conditions for the spread of the disease.
If the disease is in the initial stage, 20% cow dung extract can be sprayed twice at 15 days interval. To control developed symptoms, 120 grams of streptomycin sulphate and tetracycline hydrochloride combination along with 500 grams of copper oxychloride mixed in 200 litres of water should be sprayed per acre. The spraying should be repeated 15 days later.
Farmers could contact the officials at the nearest Agricultural Extension Centres for more details and appropriate advice, Agriculture officials said.
