C/O: xanthomonas campestris pv malvacearum
Attack all stage of plant.
- Small, water-soaked, circular or irregular lesions develop on the cotyledons.
- Later, the infection spreads to stem through petiole and cause withering and death of seedlings.
Angular leaf spot
- Small dark green water soaked area developed on the lower surface of leaves.
- Angular spot are restricted by vein and veinlet and spot are visible on both surface of leaf.
- At lesion are older, they turn to radish brown color.
Vein blight or vein necrosis or black vein:
- The infection of veins causes blackening of the veins and veinlets, gives a typical ‘blighting’ appearance. On the lower surface of the leaf, bacterial oozes are formed as crusts or scales.
- The affected leaves become crinkled and twisted inward and show withering.
- On the stem and fruiting branches, dark brown to black lesions are formed, which may girdle the stem and branches to cause premature drooping off of the leaves, cracking of stem and gummosis, resulting in breaking of the stem which hang typically as dry black twig to give a characteristic “black arm” symptom.
Square rot / Boll rot:
- On the bolls, water soaked lesions appear and turn into dark black and sunken irregular spots.
- The infections on mature bolls lead to premature bursting of bolls.
- The bacterium spreads inside the boll and lint gets stained yellow because of bacterial ooze.
Join the conversation