Fusarium Wilt Of Cotton

Description about Fusarium Wilt Of Cotton

1. COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore-3) Kullapuram (Po), ViaVaigai Dam, Theni-625 562 FUSARIUM WILT OF COTTON Course teacher: Student: Dr. Parthasarathy . S Miss.Sharmitha.S Asst.Professor (Plant Pathology) 2015021116

2. FUSARIUM WILT OF COTTON

3. CAUSAL ORGANISM   Fusarium oxysporum   f. sp .  vasinfectum ( W.C.Snyder & H.N.Hansen ) W.C. Snyder & H.N. Hansen, (1940

4. SYSTEMIC POSITION Kingdom :   Fungi Phylum :   Ascomycota Subphylum :   Pezizomycotina Class :   Sordariomycetes Subclass :   Hypocreomycetidae Order :   Hypocreales Family :   Nectriaceae Genus :   Fusarium Species :   Fusarium oxysporum f. sp. vasinfectum

5. ORIGIN Wilt is one of major disease of cotton, found wherever this crop is grown. Fusarium wilt have been originated in Mexico or Central America.

6. In India the disease was reported from Maharashtra, Tamil Nadu, Karnataka and other states.  OTHER HOSTS Bhendi , Tobacco, Brinjal and Chillli .

7. PATHOGEN The fungus is present both inter and intra cellularly in the host tissue. The Mycelium plugs the xylem vessels partially or completely. The macro conidia are 1-5 septate , hyaline, thin walled, linear to falcate, tapering ends.

8. Micro conidia are hyaline, thin elliptical to spherical, single or two celled. Fungus also produces vivotoxin , fusaric acid which is partially responsible for the wilting.

9. Microconidia Macroconidia Chlamydospores

10. SYMPTOMS Yellowing and browning of the cotyledons. Leaves lose their turgidity. First turn yellow and then brown and finally drop off. The tap root stunted and laterals are less abundant.

11. Browning and blackening of vascular tissues. Discolorations of leaves starts from the margins and spread towards midribs. Wilting may be complete or partial. 

12. YELLOWING AND DRYING OF LEAVES © Agropedia

13. BROWNING OF VASCULAR TISSUES © Agropedia

14. ©Cotton.tamu.edu

15. © AgroAtlas

16. © Agropedia

17. © Agropedia

18. FAVOURABLE CONDITION Soil temperature of 20-30˚C. Hot and dry periods followed by rains. Heavy black soils with an alkaline reaction. Increased doses of nitrogen and phosphatic fertilizers.

19. F. oxysporum f. sp. vasinfectum grows and develops at temperatures from 10 to 35°C. Optimum conditions are temperatures 18-27°C. Soil humidity 40 to 70% and acidity of environment near pH=5.3.

20. MODE OF SPREAD Fusarium wilt is spread over long distances in contaminated soil. Contaminated soil can be carried on the roots of host plants, boots and clothing, vehicles, machinery and equipment. Fusarium can also be carried in contaminated plant material, or on seeds.

21. FUSARIUM OXYSPORUM LIFE CYCLE

22. MANAGEMENT Treat the acid delinted seeds with Carboxin or Carbendazim at 2 g/kg. Remove and burn the infected plant debris. Apply increased doses of potash with a balanced dose of nitrogenous and phosphatic fertilizers.

23. Apply heavy doses of farm yard manure or other organic manures. Grow disease resistant varieties of G. hirsutum   and  G. barbadense   like Varalakshmi , Vijay Pratap , Jayadhar and Verum . Spot drench with Carbendazim 1g/ litre .

24. REFERENCES http://agropedia.iitk.ac.in http://apsjournals.apsnet.org/pdfplus R.S.Singh , Ninth edition, 2013, Plant Diseases, Oxford& IBH Publishing Company Pvt.Ltd , New Delhi.