ascochyta blight of chickpea

symptoms, pathogen, management

1. SUBMITTED BY COURSE TEACHER POORANI. S Dr. S. PARTHASARATHY ID. No. 2016021031 Asst . Prof. , (Plant Pathology ) COLLEGE OF AGRICULTURAL TECHNOLOGY Affiliated to Tamil Nadu Agricultural University, Coimbatore Kullapuram , Via Vaigai dam, Theni-625 562 ASCOCHYTA BLIGHT OF CHICK PEA

2. A ASCOCHYTA BLIGHT OF CHICKPEA ©https://mobile.abc.net

3. SIGNIFICANCE Chickpea is the third most important food legume crop. It is grown in 11m ha with 9 million ton production. Ascochyta blight of chick pea is caused by fungal pathogen Phoma rabiei (formerly known as Ascochyta rabiei ). Grain yield and quality losses up to 100%.

4. GLOBAL DISTRIBUTION The disease is worldwide in distribution, first described in India by Butler in 1911 and occurs in epidemic forms in Punjab and Jammu. The occurrence of AB of chickpea has been reported from 35 countries across six continents. 20 epidemics region occurred in Pakistan, India and European countries. In 1998 there was a serious outbreak of the disease in Victoria, South Australia and New South Wales which destroyed many crops.

5. GLOBAL DISTRIBUTION OF ASCOCHYTA BLIGHT OF CHICKPEA ©fao.org

6. INDIA LEVEL DISTRIBUTION ©link.springer.com

7. SYMPTOMS The initial symptom of the disease appears near the tip of young shoot and top most leaves. The fungus attacks all above-ground plant parts like leaves, stems and pods at any stage of the plant growth. But plants are most susceptible to disease during flowering. Pale green-yellow, circular, depressed lesions appeared on leaves and pods.

8. SS Elongated lesions on petioles and stem. Stem lesions often gridle the stem of the plant. Pycnidia may be formed on these lesions usually in concentric rings. Infected seed may discoloured, shriveled and pycnidia may be present on such seeds.

9. LEAF LESION ©www.pulses.com

10. C CONCENTRIC RINGS IN PODS ©agropedia.iitk.ac.in

11. I INFECTED SEEDS INFECTED STEM ©agropedia.iitk.ac.in

12. SYSTEMATIC CLASSIFICATION Kingdom :Fungi Phylum : Ascomycota Class : Dothideomycetes Sub class : Pleosporomycetidae Order : Pleosporales Family : Didymellaceae Genus : Ascochyta Species : A . rabiei (Pass) Labr ., (1931)

13. PATHOGEN CHARACTERS Ascochyta rabiei (exists both as an anamorph (asexual) and teleomorph (sexual) Didymella rabiei . Mycelium – pale cream coloured. Fruiting bodies Asexual- Pycnidia Sexual- Pseudothecia

14. Spores Asexual- Pycnidiospores Sexual- Ascospores The conidia are oval to oblong, one to two celled, thin walled and hyaline but pinkish in mass and measuring 9-20 × 3-6µ. They germinate in water with long germ tubes.

15. CONIDIA OF ASCOCHYTA BLIGHT OF CHICKPEA ©agementnetwork.org

16. PYCNIDIA OF ASCOCHYTA BLIGHT OF CHICKPEA ©agementnetwork.org

17. ©slideshare.net

18. DISEASE CYCLE OF ASCOCHYTA BLIGHT OF CHICKPEA ©https:// scialert.net

19. EPIDEMIOLOGY MODE OF SPREAD PRIMARY SPREAD: Seed transmission ensures random distribution of the pathogen in a field. SECONDARY SPREAD: Conidia and ascospores are responsible for secondary spread of the disease. It may also be dispersed by rain splashes, wind, water flow and contaminated machinery.

20. MODE OF SPREAD: The fungus survives on the infected seeds and plant residues. The fungus survives for some time in the host tissue, both in the form of pycnidia and peridia and perithecia . It is seed borne both internally and externally.

21. FAVOURABLE CONDITION Temperature between 20-25ºC, leaf wetness period of 10-17 h are favourable for disease development. The rainfall should be more than 350mm and followed by high humidity favours this disease.

22. MANAGEMENT Sow disease free seed. Removal and destruction of dead plant debris. Follow crop rotation. Intercrop with wheat, barley and mustard. Grow resistant varieties like Pusa 408, Pusa 417, ICL 6328.

23. Seed treatment with Carbendazim ( Bavistin ) @ 1g/kg of seed. Hot water seed treatment (52ºc for 10 min) to lower the infestation. Fungicides : Spray Mancozeb ( Indofil M – 45) @ 2.5 g/lit. Spray wettable sulphur @ 2.3 g/lit of water.

24. MANCOZEB ©indofilcc.com

25. REFERENCES Singh.S.K ., D.Singh and A.Kumar , 2017, Plant Diseases and Their Management, Kalyani Publishers, New Delhi. Singh.R.S .,Vinod kumar J ain, 2018 , Plant Diseases , Scientific International (Pvt.) Ltd., New Delhi.