CASTOR SEEDLING BLIGHT ,CASTOR RUST

SYMPTOMS, PATHOGEN, MANAGEMENT

1. SUBMITTED BY COURSE TEACHER ROSHAN SARMILA. A Dr. S. PARTHASARATHY ID. No. 2016021038 Asst . Prof. , (Plant Pathology ) COLLEGE OF AGRICULTURAL TECHNOLOGY Affiliated to Tamil Nadu Agricultural University, Coimbatore Kullapuram , Via Vaigai dam, Theni-625 562 CASTOR SEEDLING BLIGHT

2. SIGNIFICANCE Castor oil plant ( Ricinus communis L., Euphorbiaceae ) - Nonedible oilseed crop of arid and semi arid regions of India. Originates from tropical Africa. Seeds contain Ricin – extremely toxic protein. Oil has industrial and medicinal uses such as nylon, fibre , jet engine lubricants, dyes, soaps, oinments , paints, varnishes.

3. In world, India is largest producer – 55-60 % TGP Area - 12.33 lakh ha Production - 19.64 lakh t Productivity - 1592 kg / ha In India, Gujarat is largest producer – 14.93 lakh t

4. DISEASE Seedling blight – Phytophthora nicotianae (= P. parasitica ) ( Dastur ) water house. Common disease in India. First reported from Pusa , Bihar ( 1909) in moderate to severe form. Seedling mortality – 30- 40% Favoured by ill drained and prolonged rainy season( end of june to september ).

5. Also reported in UP in 1948 and Hydrebad in 1947. DISTRIBUTION: UP, AP, Telangana , Karnataka, Bihar, Gujarat.

6. Spot on older leaves Leaf blighting Dead seedling © Vikaspedia.in

7. SYMPTOMS: Leaves -Circular, dull green patch on both surface. Spreads and leaf to rot and hanging down. Stem - Cause withering and death of seedling due to destruction of growing point or by the collapse of stem. Initailly on young leaves and spread petiole, stem causing black discolouration and severe defoliation.

8. Spot on older leaf: Leaf spots turn yellow and then brown concentric zones of lighter and darker colour formed. Affected leaves shed prematurely. Moist – very fine whitish haze is found on under surface of the leaf spot. Direct attack of stem is not very common if it means damage is less due to the presence of cuticularised epidermis in older leaves resist penetration.

9. PATHOGEN: Non septate , inter and intra cellular hyalin mycelium. Sporogiophores emerge through the stomata on the lower surface singly or in groups. A single colourless ovoid or roundish sporangium is borne at the tip of sporongiophores .

10. A ripe sporangium liberates zoospores when put in water. Which varies from 5 to 45 in each sporangium. Fungus also produces oospore and chlamydospores . It also produces infection on the leaf of sesamum , this might serve as a collatral or alternative host of the fungus. Aesexual spore: Zoospore. Sexual spore: Oospore .

11. Zoospore ©Forestryimages.org

12. LIFECYCLE © researchgate.net

13. SYSTEMATIC POSITION Kingdom: Chromista Phylum: Oomycota Class: Peronosporea Order: Peronosporales Family: Peronosporaceae Genus: Phytophthora Species: parasitica

14. FAVOURABLE CONDITION: Continuous rainy weather. Low temperature (20-25◦C). Low lying and ill drained soils. MODE OF SPREAD: Primary source : Pathogen remains in soil as chlamydospores and oospores. Fungus also survive on host like potato, tomato, brinjal , sesamum . Secondary source: Wind borne sporangia.

15. MANAGEMENT: Ill drained, damp, low lying localities should be avoided for sowing castor. Seed dressing with 4g Trichoderma viride formulation and 3g Metalaxyl (Phenyl amide compound) per kg of seed. Soil drenching with Copper oxychloride (Blue copper) @ 3g/lit or Metalaxyl 2g/lit.

16. SUBMITTED BY COURSE TEACHER ROSHAN SARMILA. A Dr. S. PARTHASARATHY ID. No. 2016021038 Asst . Prof. , (Plant Pathology ) COLLEGE OF AGRICULTURAL TECHNOLOGY Affiliated to Tamil Nadu Agricultural University, Coimbatore Kullapuram , Via Vaigai dam, Theni-625 562 CASTOR RUST

17. CASTOR RUST © bowerbird.org.au

18. CASTOR RUST Melompsora ricini It has been recorded on castor oil plant, in Africa, Asia and southern Europe. M. ricini known only on its uredinial and telial states. In Australia, M. ricini was first collected (BRIP 25782) in Brisbane in Auguest , 1999. Within weeks the rust was found in perth . Yield loss 89.9%, affects rearing of eri silkworm.

19. SIGNIFICANCE Controlling the rust with hyperparasites has been attempted but not found to be economic importance. It is suggested that at the first sign of infection, diseased leaves should be destroyed.

20. SYMPTOMS Minute, orange-yellow coloured , raised pustules appear with powdery masses on the lower surface of the leaves and the corresponding upper surface of the leaves are yellow. Often the pustules are grouped in concentric rings and coalesce together to for drying of leaves. Pale leaf spots eventually develop into spore producing structures called pustules.

21. Some cases there may be dozen of pustules on a single leaf. Severely affected often turn yellow and fall prematurely. Heavy infection often reduces the vigour of the plant. In extreme cases (e.g. with antirrhinum rust) the plant can be killed.

22. PATHOGEN The hyphae collect beneath the epidermis of the leaf and form a minute cushion. The urdeospores arise beneath the epidermis on the tips of branched hyphae . Stout club-shaped paraphyses are also formed in the sorus .

23. At maturity the epidermis ruptures releasing clouds of spores. The uredospores are round or eliptic , warty and orange in colour and measure 25-29 × 19-25µ. They germinates by germ tube which comes out from the pores and infects fresh leaves of castor. Melompsora ricini is pathogenic to Euphorbia obtusifolia , E.ipecacuanha , E.geniculata and E.marginata besides 24 strains and varieties of R.communis .

24. ©Collections.daff.qld.gov.au

25. SYSTEMIC POSITION Kingtom : Fungi Phylum: Basidiomycota Class: Urediniomycetes Order: Uredinales Family: Melampsoraceae Genus: Melampsora Species: ricini

26. Spreads: 1. Chiefly by urediospores , and sometimes by wind. Distribution: 1. The disease occurs in Bombay, Deccan districts, Coimbatore and Nagpur. 2. It usually appears in Bombay between November and February on castor sown in June.

27. Favourable condition Common in India – Nov-Feb-Annual crops. Geographical distribution: Africa (Algeria, Congo, Egypt, Ethiopia, Kenya, Libya, Malawi, Morocco, Mozambique, Rhodesia, Sudan, Tanzania, Uganda); Asia (Ceylon, Cyprus, India); Europe (Italy, Lusitania, Portugal). (From the literature and Herb. IMI)

28. HOSTS On Ri c inus communis ; also by inoculation on 1 . Euphorphia geniculata , 2. E. ipecacuanha , 3. E. marginata , 4. E. obtusifolia .

29. MANAGEMENT Rogue out the self sown castor crops and other weed hosts. Spraying the crop with fine sulphur powder @20-30 kg /ha. Spray Mancozeb ( Indofil M-45) at 2kg/ha or Propioconazole (Tilt) 1 lit/ ha.

30. REFERENCE Das.P.C ., 2018. Plant Disease. Kalyani Publishers, Ludhiana. Rangaswami.G ., Mahadevan.A ., 2016. Disease of Crop Plants in India. (Fourth edition). PHI learning private limited Delhi. Agritech.tnau.ac.in/crop-protection/crop-prot-crop%20disease-oilseeds-castor.html