Yellow sigatoka disease is caused by Mycosphaerrela musicola. It is characterised by appearance of small yellow specks (1-
2mm long) on the leaf, parallel to the secondary veins of the blade.
The Yellow specks develop into necrotic spots, which are more or less round and are surrounded by a yellow halo.
The necrotic pathes may go up the leaf.
The lesions on most susceptible clones past through six stages to maturity
- Minute yellowish green specks
- Specks grow into yellowish green to yellow streaks,visible on the upper side of the leaf
- The streaks expand and gradually change to brown orrusty red spots with undefined margins
- The spots obtain a definite outline with a brown centre and a yellow to light brown halo sometimes with awater soaked centre
The dark centre sinks and the water halo turns darker brown
- The sunken central area turns grey and is surrounded by a dark brown or black border with a yellow halo
between the border and the normal green leaf.