Cotton leaf curl virus

PAT 301

1. COTTON LEAF CURL VIRUS COURSE TEACHER: Dr. PARTHASARATHY S Asst. Professor (Plant Pathology) STUDENT: Mr. SURESH.L ID. NO. 2016021044 COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore3 ) Kullapuram (Po), Via Vaigai Dam, Theni-625 562

2. HISTORY & SIGNIFICANCE The disease was first reported on Gossypium barbadense from Nigeria in 1912 and is known to occur on Abelmoschus esculentus and Corchorus fascicularis also. Later on reported from Tanzania and Sudan in 1926 and 1934 respectively. It is a major disease of cotton in Asia and Africa.

3. 123rf.com

4. HISTORY & SIGNIFICANCE In Asia ,it has been reported from Pakistan and Western India inciting severe disease symptoms characteristics to this disease. In Pakistan cotton leaf curl virus was reported for the first time in 1967 near Multan. Severe epidemics of cotton leaf curl disease have occured in Pakistan in the past few years with yield losses as high as 100% in fields where infection occured early in growing season.

5. HOST PLANTS Gossypium spp. mainly Gossypium barbadense OTHER HOSTS: Hibiscus esculentus H. cannabinus H. sabdariffa Phyllanthus niruri Abutilon sp . Petunia spp .

6. SYMPTOMS The infected plants remain stunted and their leaves show distinct upward and downward curling. The curling occurs due to increase in interveinal tissues. Enation on the veins on underside of leaves which develop into large leaf like outgrowth. Chlorosis,thickening and malformation of veins,petioles and leaves are commonly observed.

7. SYMPTOMS Infected plant give bushy appearance. Vein swelling. Back-lighting shows the characteristic dark vein. Leaves become leathery texture and look thick. Leaves may look wilted.

8. SYMPTOMS OF CLCuV (a) Normal leaf (b) Infected leaf alchetron.com

9. Infected plant alamy.com

10. Vein thickening and leaf enation Leaf enation Vein thickening Padil.gov.au

11. SYSTEMATIC POSITION Domain : Virus Unknown : “ ssDNA viruses” Family : Geminiviridae Genus : Begomovirus Species : Cotton leaf curl virus, Tobacco streak virus

12. CAUSAL ORGANISM The virus belongs to the subgroup of Geminivirus . Analysis of nucleic acid sequences has indicated that cotton leaf curl virus is closely related to tomato yellow leaf curl virus, cassava latent virus and indian cassava mosaic virus.

13. DISEASE CYCLE Chilli pepper often overlaps the cotton crop and might serve as an important inoculum for the disease development. Okra crop is also considered to be the important source of inoculum . Chilli pepper has been shown to contain begomo viruses and a distinct DNA has been isolated but there is no report of cotton leaf curl affecting chilli pepper. The disease is known to be transmitted by whitefly vector- Bemisia tabaci .

14. Vector - Whitefly Commons.wikimedia.org

15. FAVOURABLE CONDITIONS Cotton leaf curl virus disease ( CLCuD ) is affected by climatic condition like rainfall, wind and temperature. Disease infestation increased in the range of maximum and minimum temperatures of 33-45°C and 25 -30°C respectively.

16. FAVOURABLE CONDITIONS Maximum disease incidence percentage was recorded at 6 week old seedlings and it gradually decreased with increase in age of the plant. Rainfall prior to seedling may result in development of an increased population of vector due to abundance in food source.

17. DISEASE MANAGEMENT Use resistant varieties X1530 and X1730 and hybrids LHH-144, CSHH 198, CSHH238. Growing of okra crop in and around the cotton field should be discouraged. Intercropping with wild species of solanum should be followed. Crop rotation with crops that are not host plants for whiteflies.

18. DISEASE MANAGEMENT Affected plants should be rogue out. Destroy off-season weeds and clean cultivation during the season to minimise sources of virus inoculum . Whitefly (vector- Bemisia tabaci ) should be managed by growing whitefly resistant varieties or by judicious use of any suitable insecticide-methyl demeton , triazophos , acetamprid 20%SC and neem preparation have been found effective to control the whitefly through its application.

19. REFERENCES D.P.Tripathi , 2007, Introductory plant virology, Lyall Book Depot, Ludhiana. pp 347 Kenneth M.smith,1972, A Text Book Of Plant Virus Diseases, Longman Group Limited, London. pp 221-224

20. THANK YOU