Diseases of horticultural crops

DIseases of small Cardamom

1. COLLEGE OF AGRICULTURAL TECHNOLOGY ( Affiliated to Tamil Nadu Agricultural University, Coimbatore-3) Kullapuram (Po), ViaVaigai Dam, Theni-625 562 DISEASES OF SMALL CARDAMOM SUBMITTED BY COURSE TEACHER M. UTHAYAKUMAR Dr. PARTHASARATHY. S 2015021134 Asst. Prof. PLANT PATHOLOGY

2. 1. CHENTHAL DISEASE Also called as Leaf blight of cardamom Anamorph (Asexual stage) Colletotrichum gloeosporioides Teleomorph (Sexual stage) Glomerella cingulata

3. DISTRIBUTION Leaf blight of cardamom, popularly known as Chenthal was first reported from Vandenmedu village of Idukki district in Kerala. The disease is widely distributed in all the cardamom growing regions of South India.

4. The disease mainly affects foliage and by destroying the effective photosynthetic area, it adversely affects fruit set and capsule weight. Chenthal results in a yield reduction of 7-13% in Mysore type of cardamom.

5. SYSTEMATIC POSITION Kingdom : Fungi Division : Ascomycota Class : Sordariomycetes Order : Glomerellales Family : Glomerellaceae Genus : Colletotrichum Species : C. gloeosporioides

6. SYMPTOMS Elongated, water soaked lesions of varying size appear on the upper surface of the leaf. The spots becomes brown to dark with pale yellow hole. Leaves wither and pseudo stem wilts. New shoots which develop are reduced in size. Flowers fail to develop. The inflorescence dry up starting from tip downwards. The affected garden shows burnt appearance.

7. https://www.apsnet.org

8. PATHOGEN CHARACTER It produce acervuli which is rounded or irregular in shape. Conidiophore – simple, septate . Conidia – cylindrical, non septate with oil globules.

9. MODE OF SPREAD Primary spread : Through a scospores from dried fallen leaves. Secondary spread : Wind borne conidia.

10. FAVOURABLE CONDITIONS Continuous rain fall. High relative humidity. The disease which appears during mid- monsoon, becomes severe during late monsoon periods.

11. MANAGEMENT Chemical methods: Spray the crop with carbendazim ( 0.1%) or carbendazim (0.05 %) + mancozeb (0.02%) at 10 – 14 days interval.

12. Biological control: Apply biocontrol agents like Bacillus subtilis and Trichoderma viride . Biopesticide : Spray extracts of Artemisia vulgaris and Schima wallichi choisy .

13. 2. AZHUKAL DISEASE Also called as Capsule Rot Causal organism Phytophthora nicotianae var . nicotianae

14. SYSTEMATIC POSITION Domain : Eukaryota Kingdom : Chromista Phylum : Oomycota Class : Oomycetes Order : Peronosporales Family : Peronosporaceae Genus : Phytophthora Species : Phytophthora nicotianae

15. SYMPTOMS Large irregular water soaked dirty black lesions appear on mature leaves. The leaves shred and get attached to the pseudostem Greyish patch of irregular brownish margin seen on the base of the leaf sheath. The basal portion of the pseudostem breaks.

16. Small light brown lesions develop on the tender fruits which fall prematurely. Blackish discolouration on the fruit wall. The tips of the inflorescence rot.

17. http://agritech.tnau.ac.in/

18. PATHOGEN CHARACTER Intercellular mycelium . Zoospores are reniform , biflagellate , oogonia are spherical, antheredia is amphigynous and often curved. Oospores are spherical with smooth wall.

19. MODE OF SPREAD Primary spread : Soil borne oospores Secondary spread: Water borne pathogen

20. MANAGEMENT Removal and burning of infected plants. Avoid moving of rhizomes from diseased areas to healthy area for planting. Provide proper drainage. Three sprays with Bordeaux mixture 1% in May, June, July. Soil drench with Bordeaux mixture 1% (or) Copper oxychloride  0.25 %.

21. 3. DAMPING OFF Also called as Rhizome rot, Clump rot. Causal Organism : Pythium vexans

22. SYSTEMATIC POSITION Domain : Eukaryota Kingdom: Chromista Phylum : Oomycota Class : Oomycetes Order : Pythiales Family : Pythiaceae Genus : Pythium Species : Pythium vexans

23. SYMPTOMS Pale yellow young foliage. Rotting of rhizomes. Shoots become very brittle and later collapse.

24. PATHOGEN CHARACTER Inter and Intra cellular mycelium. Zoospores are reniform , biflagellate , oogonia are spherical, antheredia is often curved. Oospores are spherical with smooth wall.

25. MODE OF SPREAD Primary spread : Soil borne oospores Secondary spread: Water borne zoospores

26. MANAGEMENT Destruction of diseased clumps. Providing proper drainage. Changing the nursery site. Drenching the nursery beds with Copper oxychloride 0.25% or Bordeaux mixture 0.5%, before 15 days of sowing. Soil drenching with Bordeaux mixture 1 %

27. 4. CARDAMOM MOSAIC Also called as katte disease of cardamom Causal organism: Cardamom mosaic virus (RNA virus)

28. SYMPTOMS C hlorosis of young leaves – parallel streaks of pale green tissues running along the veins from midrib to the margins. Leaf sheath also shows stitch stripes. In advanced stage the whole plant shows mosaic symptom. Rhizome shrivels and plants dies. If young clumps are attached they die before flowering.

29. MODE OF SPREAD Primary spread: Infected rhizome Secondary spread: Aphid – Pentalonia nigronervosa

30. MANAGEMENT Collection and removal of infected clumps along with rhizomes and burning. Raising of nursery in diseases free areas. Spray with D imethoate (or) Methyl Dematon (or) Phosphomidon to kill the vector.

31. REFERENCES D.Alice , C.Jeyalakshmi , Plant Pathology , third edition, A.E Publication, Coimbatore. R.S.Singh , Plant Diseases , Oxford and IBM Publishing Co. Pvt. ltd. 9 th edition, New Delhi .