Fibre yielding plants

Leaf spot disease of Madaar

Host: Calotropis procera (Madaar, Aak)
Pathogen: Cercospora

Symptoms

Leaf of Aak (madaar) showing black spots

Shot-holes in aak leaves 

The disease appears as a grey spots on both the surfaces of leaf. Soon, the spots become black-brown in color. Later on, whole the leaf is covered by numerous such spots. As the spot ages, the center of it is decayed and torn-out forming shot-hole.

Pathogen

Conidiophores of
Cercospora

Cercospora is a biotroph (obligate parasite). The hyphae are well branched and septate. Mycelium grow intercellularly and produce haustoria in the host cell for absorption of nutrients. In the stomatal chamber hyphae produce stromal mass. The stromal mass produces conidiophores on both the leaf surfaces. Conidiophores arise through the stomatal pores.
At the tip of conidiophore single long, cylindrical and multiseptate condium is produced acrogenously. After formation of conidium, the growth of conidiophore continues sub-apically which pushes the mature conidium a side. After detachment of conidium, a geniculate scar is left at the attachment point which appears as knee-shaped bending.