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Shri Shivaji Education Society, Amravati’s�JIJAMATA MAHAVIDYALAY, BULDANA�Department of Botany� � Programme: B. Sc. Botany�(B.Sc. Part I) Semester I �Code of the Course/Subject : BOT(1S)/Botany ��Title of the Course/Subject: DIVERSITY OF MICROBES, PHYCOLOGY, MYCOLOGY AND PHYTOPATHOLOGY � �UNIT-VI : Phytopathology ��Topic: 6.4 Symptoms, pathogen biology and disease management of fungal diseases ��6.4.1. Tikka disease of groundnut �6.4.2 Powdery mildew of Tectona grandis (Teak) � �Name of Teacher�Dr. Rahul W. Ukey (Assistant Professor)�

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6.4 Symptoms, Pathogen Biology and Disease Management of Fungal Diseases �

6.4.1. Tikka disease of Groundnut

Symptoms:

1. Tikka disease of groundnut (Arachis hypogaea; vern.' moongphali; fam. Papilionaceae) is caused by Cercospora personata and C. arachidicola.

2. Symptoms fIrst appear in one or two month old plants.

3. The leaves show excessive spotting causing defoliation. This results in fewer and smaller nuts.

4. The fIrst symptoms appear in the form of pale areas on the upper surface of older leaves.

5. Circular or irregular reddish brown to brown lesions are formed. These are larger in size on the lower leaf than on the upper.

6. The spots are surrounded by a narrow yellow halo. These are indistinct on the lower surface than on the upper.

7. Disease is soil borne and can be controlled by crop rotation, seed treatment with agrosan GN and CUS04, and fungicides like Bordeaux mixture, Dithane M-15, Benlate, etc.

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6.4.2 Powdery mildew of Tectona grandis (Teak)

  • Members of the family Erysiphaceae have been recorded to cause mildews in teak. 
  • Phyllactinia corylea is recorded to attack teak laves (Bagchee, 1952). 
  • Phyllactinia guttata is also recorded to attack teak from other countries. 
  • Uncinula tectonae, widely occurs in nurseries and forests in central and southern India.

Symptoms:

  1. The fungus forms white powdery coating on the undersurface of teak leaves and later develops dark coloured cleistothesia over the white fungus weft (Spaulding, 1961). 
  2. Uncinula tectonae is restricted to the upper leaf surface and the infected leaves are coated with a dull white mycelium and conidia borne on conidiophores.
  3. Conidia are air-borne which are produced abundantly and cause fresh infection.
  4. The metabolic changes in plants take place which lead to drying of infected leaves.�

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Control Measures:

�            Sulphur dust was most effective in controlling powdery mildew in two year old seedlings followed by Baycor, Mortesan and Calixin (Kulkarni and Siddaramaiah, 1979).