Bacterial blight was first observed in Tamil Nadu.
High temperatures ranging from 30-40°C and relative humidity of 85% are favourable conditions for the occurrence of this disease.
Damage Symptoms:
Small, water-soaked lesions, either circular or irregular in shape, first appear on the cotyledons. The infection then spreads to the stem, causing wilting and death of the seedlings.
On the lower surface of the leaves, dark green, water-soaked areas form, and these gradually enlarge and become angular.
As the lesions mature, they turn reddish-brown, and the infection spreads to the veins and veinlets, which blacken, resulting in a characteristic "blighted" appearance.
The affected leaves become crinkled, twist inward, and eventually wilt.
Dark brown to black lesions develop on the stem and fruiting branches. These lesions may girdle the stem and branches, causing premature leaf drop, stem cracking, gummosis, and stem breakage, often leaving the stem hanging as a dry black twig, which is referred to as the "black arm" symptom.
Water-soaked lesions also form on the bolls, turning dark black and sunken, and the infection spreads, ultimately causing boll shedding.
Preventive Measures:
Remove and destroy infected plant debris.
Practice crop rotation with non-host crops.
Control Measures:
Spray Streptomycin sulfate along with Copper Oxychloride at a rate of 0.3%.
