cowpea mosaic virus, cowpea aphid mosaic virus

SYMPTOMS, PATHOGEN, MANAGEMENT

1. STUDENT COURSE TEACHER POORNIJA. N Dr. S. PARTHASARATHY ID . No. 2016021032 Asst . Prof., (Plant Pathology ) COLLEGE OF AGRICULTURAL TECHNOLOGY Affiliated to Tamil Nadu Agricultural University, Coimbatore Kullapuram , Via Vaigai dam, Theni-625 562 COWPEA MOSAIC VIRUS COWPEA APHID MOSAIC VIRUS

2. COWPEA MOSAIC VIRUS C COECO @ Scilelo.br

3. SIGNIFICANCE Cowpea is an important crop suitable for intercropping. It prevents soil erosion. Cowpea are useful even the leaves which can produce 9 times the calories, 15 times the protein, 90 times the calcium and beta carotene of cowpea seeds. It causes 66% of yield loss when infected during growth phase (24 DAS).

4. First reported in vigna unguiculata from Louisiana, USA by Perez and Cortez Monllor in 1970. @ wikipedia.com

5. GLOBAL DISTRIBUTION The disease is present in North American and Southern American region but not in Peru. The virus is predominant in Rorem state and northern regions of Brazil. @ @ apsnet.org

6. SYMPTOMS Chlorotic lesions Concentric ring spots Vein clearing Mosaic Malformation and blistering of young leaves. @ aspnet.org

7. PATHOGEN Group : Group IV (+ ssRNA ) Order : Picornavirales Family : Secoviridae Subfamily : Comovirinae Genus : Comovirus Species : Cowpea mosaic virus

8. PATHOGEN CHARACTERS Obligate parasite. Cannot exists as saprophytes. It is a non enveloped plant virus. Its genome consists of 2 molecules of positive sense RNA ( RNA1 and RNA2). The virus particle are 28 nm in diameter and contain 60 copies each of a large (L) and small (S) coat protein.

9. The virus particles are thermostable . It can be isolated easily from plants. @ viralzone.com

10. HOSTS Chenopodium amaranticolor Phaseolus vulgaris Vigna unguiculata Soyabean Pigeon pea 2 @Iclane.net

11. DISEASE CYCLE The virus is transmitted by chrysomelid beetles viz., ootheca mutabilis , Cerotoma variegata , C.ruficornis . Transmitted by various beetles with biting mouthparts. The transmission is characterized as short acquisition and inoculation access periods and a lack of a latent period.

12. The beetle viruliferous 1-8 days depending upon the species. Ootheca mutabilis Cerotoma variegata Cerotoma ruficornis @ @ iNaturalist.org

13. MANAGEMENT Remove the infected plants as soon as symptoms appear. Grow resistant varieties. Rogue out and destroy the weed hosts. Sowing of cowpea crop away from soyabean and pigeon pea.

14. C Cowpea Aphid mosaic virus

15. SIGNIFICANCE It is a seed borne virus disease of cowpea. It causes a yield loss of 13-87 % under field condition.

16. GLOBAL DISTRIBUTION Northern Italy S preaded all over the world.

17. SYMPTOMS First systemic symptoms appear about 10 days after infection and consist of a dark vein banding. Blistering of leaves. Irregular vein banding. @ @ researchgate.net

18. PATHOGEN Group : Group IV (+ ssRNA ) Order : Unassigned Family : Potyviridae Subfamily : Potyvirinae Genus : Potyvirus Species : Cowpea aphid-borne mosaic virus

19. PATHOGEN CHARACTERS It is a poty virus. It is a cosmopolitan. It is an obligate parasite. The virus particles are rod shaped of length about 750 micrometer.

20. HOSTS Chenopodium album Vigna sinensis Glycine max Petunia hybrida @ thompson-morgan.com

21. DISEASE CYCLE The virus is mechanically transmissible preferably by use of carborundum and phosphate buffer (0.01M). It is a seed borne in cowpea and the vector are the aphids, Myzus persicae , Aphis gossypii , Aphis craccivora . The virus is stylet borne.

22. Myzus persicae Aphis craccivora Aphis gossypiii @ influentialpoints.com

23. EPIDEMOLOGY PRIMARY SPREAD is virus infected seed that acts as primary inoculum . SECONDARY SPREAD is aphids under field condition. @ viralzone.expasy.org

24. MANAGEMENT Growing of resistance varieties (TVU-15656) Intercropping of cowpea with cereals. Production of virus free seeds. Synthetic pyrethroids are used for restricting the inoculation of virus.

25. REFERENCES Smith kenneth , M.1972.A Textbook of Plant virus D iseases.Longman group limited, London. Sing Ajith,Kr ., R,K,S,Tiwari.2016.Handbook of Plant P athology . Kushal Publications and distributors, Varanasi. https://www.viralzone.expasy.org/ https://www.plantwise.org/knowledgebank/datasheet.aspx?dsid=15649 https://www.apsjournals.apsnet.org/ https://www.tandfonline.com/doi/abs/10.1080/09670870110118722?journalCode=ttppm20