Tikka disease

tikka disease

1. Tikka disease of Groundnut ANJALI MSC Microbiology 3 rd sem SGRRU

2. Content Introduction Causal Organism Symptoms Disease Cycle Favourable Condition Disease Management Conclusion Reference

3. Introduction Groundnut is the most important oilseed crop of india The total area under ground nut is about 8 million hectares Tikka disease is the major disease of groundnut In india It occurs in every state in India and in every ground of nutgrowing countries of the world In Uttar Pradesh , the disease locally known as chitwa or haldai

4. Causal organism The causal organism of this disease are Cercospora personata and Cercospora arachidicola The symptom caused by the two pathogen will differ This disease also called Leaf spot of Ground nut because it causes Leaf spot on the leaves

5. Symptoms Symptoms appear when the plants are 1 or 2 months old Due to excessively spotting on the leaves , there is gradual weakening of the foliage which results in defoliation Consequently , fewer and smaller nurs are formed According to sundarram (1965) severe intensity of infection leads upto 22% reduction in yield

6. Symptoms C.arachidicola causes early spot and C.personata causes late spot First symptom of both leaf spots is the appearance of pale areas on the upper surface of older leaves As the lesion develops the two species can ve distinguished

7. Early leaf spot symptoms Sub circular dark brown spots are produced on the upper leaflet surface Spots are of lighter shade of brown on the lower side of leaflets Yellow halo is seen around the brown spots

8. Late leaf spot symptoms Late leaf spots are nearly circular and darker than early leaf spots Yellow halo develops around each only in later stage of development Late leaf spots can be distinguished from those of early leaf spots Late Leaf spots are darker with no or light yellow halo

9. Causal organism The mycelium of C.arachidicola is inter and intracellular,brown, septate and without haustoria. Conidiophores are yellow brown and as the conidium remains attached to geniculation oj conidiophore. Conidiophore are 22-44 micron long and 3-5 microm broaf continuous or 1-2 septate.

10. Causal organism Cercospora personata produces an intercellular branched mycelium To absorb food from the host tissue, haustoria are developed. Lesions appear 2-4 weeks later. Conidiophore of C.personata are 25-54 micron long,5-8 mircon Broad continuous or 1-2 septate. Conidia are terminal and each conidiophore bear each single conidium at the apex. It is potentially more damaging because it produces more spots, spreads faster and causes earlier defoliation.

11. Dieseade cycle Perennation The disease perpertuates through conidia lying in the soul on diseased plant debris and through conidia being carried in thr shell of groundnut. Primary Infection When the new crop of Groundnut starts growing,the viable conidia are brought to the host surface by various agencies, germinate in favourable conditions and cause primary Infection. Secondary infection The secondary infection on healthy plants in the same field or adjacent fields is brought by conidia produced on primary infected leaves.

12. Cont..... The conidia are dispersed by air or other agencies , which bring them on the healthy leaves Later , they germinate in favourable conditions and causes infection

13. Favourable factors Relative humidity is the most important factor for infection A period of three days of high humidity is essential for maximum infection Prolonged low temperature and dew also favour Severe infection

14. Unfavorable condition Application of potash slightly decrease disease incidence Leaf spot development is minimal when gypsum is applied as a source of calcium

15. Disease management As the disease is soil borne, proper crop rotation is needed Plant disease debris should be burnt to avoid soil infection Early planting, alteration in date of sowing and use of maturing varieties helps to escape room the attack of disease Foliage spray with Bordeaux mixture , Dithane M-45(.2%), Benlate and Bavistin (0.1) give good result

16. Conclusion Tikka disease is the common disease in ground nut caused by Cercospora arachidicola and Cercospora personata In the diseased condition , many circular spots appear on the surface of leaf Conidia of the fungus present in soil or those present in the fruit shell is the source of infection Use of fungicides controls the disease