Leaf Blight disease:
Causal organism: Xanthomonas radicle.
Symptoms:
· Narrow, yellow, brown or orange lesion that have bight on the plant leaves.
· Lesion can extend to several inches long and stay in between leaf veins.
· Edges of lesions one wary and have a jagged appearance. This is one of biggest distinguishing from there disease.
· Symptoms often appear on the bottom leaves of plant and travel.
· Lesion can also appear or water soaked.
Favourable condition:
· Temperature: 24-30 degree.
· Relative humidity: 100%
· Pathogen is formed by warm, humid condition and is thought to spread by wind driven rain.
Disease cycle:
Perennation:
· Survive on corn residue and in the soil.
Primary infection:
· Bacteria are splashed on to corn leaves if condition are conducive (warm and humid).
Secondary infection:
· By rain drops and especially under windy storm
Diagram of leaf blight disease cycle in maize crop:
Management:
Cultural method
· Do not grow maize in low, wet fields.
· Provide adequate soil drainage.
· Control grass weeds in or around the maize fields.
· Deep ploughing.
· Crop rotation with pulses
Chemical method
· Treat the seeds with Metalaxyl at 4g/kg.
· Spray the crop with Metalaxyl + Mancozeb @1kg on 20th day after sowing.
