Diseases of Fruit Plantation Medicinal and Aromatic Crops

Leaf spot

Causal organism: Cercospora dioscoreae.
Symptoms

• Numerous irregular angular dark brown to black spots.
• Later the sports move to stem, the spots starts coilasce & blightning take place.
• Later the leaves fall off.
Taxonomy

Kingdom: Fungi:
Division: Deuteromycota
Class : Deuteromycetes
Order: Moniliales
Family: Dematiaceae
Genus: Cercospora
Species: dioscoreae.

Etiology

• Septate mycelia, inter & intra cellular haustoria .
• Asexual spores: Conidia.
• Sexual spores: Ascospores.
• Vegetative structures: Dormant mycelia.
Epidemiology

• Temp: 30-320C.
• RH > 90%.
• Susceptible host.
Management

• Proper nutrient management .
• N-300Kg.
• P-150Kg.
• K-150Kg./ha/yr.
• Crop rotation with non host crop.
• Chemicals:Mancozeb-0.25 % as foliar spray
LIFE CYCLE OF LEAF SPOT

• Affected plant parts having Pseudothecium as primary source of inoculums during favourable climate this will produce ascus in that ascospores are present because of lack of pressure inside the ascus they burst open and fly on to air and land on to the host, causes infection and causes leaf spot of diascoria.In the affected host conidia are present, they produces conidiophore and cause infection by flight b asexually.
• During adverse climatic conditions the fungi switched on to sexual reproduction where gametangial contact followed by plasmogamy, karyogamy, mitosis and meiosis takes place by this inoculums is reproduced .