Colletotrichum
Cercospora:-
1. Classification:-
Kingdom:- Myceteae
Division:- Amastigomycota
Sub division:- Deuteromycotina
Class:- Deuteromycetes
Sub-class:- Coelomycetidae
Order:- Melanconiales
Family:- Melanconiaceae
Genus:- Colletotrichum
2. Habit and Habitat:-
> It occurs commonly on the stem and leaves of sugarcane plants in every sugarcane- growing region, and causes the common red-rot disease of surgarcane.
> Red-Rot of Surgarcane:- It is caused by Colletotrichum falcatum.
> Colletotrichum capsici occurs on Capsicum anum.
> Symptoms of the Disease on Sugarcane:-
- The fungus mainly attacks the stems and leaves.
- The stems, at the high level of infection, get rotten and shrink at the nodes, and become dull in colour.
- The upper leaves become paler and start to droop down.
- The stem splits and many red-coloured longitudinal lines are formed on it. These lines extend through many internodes.
- The reddening is mainly in the vascular bundles and sometimes also in the pith.
- Many white patches are also present on the stem in cross-wise direction.
- The midrib of the leaves also becomes dark red.
3. Thallus Structure:-
> Mycelium is septate, branched, hyaline and intercellular or intracellular.
> Many oil drops are present in each cell of the mycelium.
> Mycelium is generally present in the cells of the parenchymatous pith.
4. Reproduction:- The fungus only reproduces asexually by forming conidia.
> The conidia develop on conidiophore, and both these structures form the fruiting body of the fungus called acervulus.
> Acervuli are saucer-shaped, flat and black velvety structures.
> In each acervulus, alongwith condidia and conidiophores, are present many long, branched and septate bristles called setae.
> Conidiophores are aseptate and cut many unicellular, falcate, hyaline conidia, which, on germination, form the new mycelium.
