Minor diseases of Maize

 Minor diseases 

1. Bacterial Stalk rot - Erwinia dissolvens

Symptoms

The basal internodes develop soft rot and give a water soaked appearance. A mild sweet fermenting odour accompanies such rotting. Leaves some time show signs of wilting and affected plants topple down in few days. Ears and shank may also show rot. They fail to develop further and the ears hang down simply from the plant.

Disease cycle

 Borer insects play a significant role in initiation of the disease. The organism is soil borne and makes its entry through wounds and injuries on the host surface. The organism survives saprophytically on debris of infected materials and serves primary inoculum in the next season

2. Mosaic - Maize mosaic potyvirus

Symptoms 

 Symptoms appear as chlorotic spots, which gradually turn into stripes covering entire leaf blade. Chlorotic stripes and spots can also develop on leaf sheaths, stalks and husks. Moderate to severe rosetting of new growth is observed. Size of stalk, leaf blades and tassel tend to be normal in late infection. 

Symptom

Pathogen 

 It is caused by Maize mosaic potyvirus. Virions are flexuous, 750-900nm long, ssRNA genome. 

Disease cycle 

 It is transmitted in nature by leaf hopper vector, Perigrimus maidis.