Loose smut and flag smut of wheat

symptoms,pathogen and management

1. STUDENT COURSE TEACHER GAYATHRI.D Dr. S. PARTHASARATHY ID . No. 2016021010 Assistant Professor (Plant Pathology ). COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore) (Accredited to Indian Council of Agriculturral Research,New Delhi) Kullapuram , Via Vaigai dam, Theni-625 562 LOOSE SMUT AND FLAG SMUT OF WHEAT

2. LOOSE SMUT SIGNIFICANCE Loose smut caused by Ustilago nuda tritici . It is one of the major diseases on wheat. There was loose smut epidemic during 1970-75 in Punjab, Haryana and Western U.P. In Sonalika , the incidence was 5 to 6%. Incidence is more in North than in southern parts of India . Country wide loss is about 2-3% in total yield.

3. DISTRIBUTION A ll wheat growing regions of India. Particularly in the Punjab, Uttar P radesh and certain districts of Madhya P radesh.

4. SYMPTOMS The destructive nature of the disease lines in the fact that every head of the affected plants maybe converted into a black mass of spores and no grains are formed. Significant reduction in height and number of tillers. Symptoms appears after ear emergence.

5. SYMPTOMS Except awns all parts of ear converted into smut spore. Black powder in ear –covered by silvery membrane. Group of smut spore called “ sorus ”. High respiration. Low dry weight of plant.

6. LOOSE SMUT OF WHEAT www.forestyimages.org

7. LOOSE SMUT OF WHEAT cropgenebank.sgrp.cgiar.org

8. Kingdom Fungi Phylum Basidiomycota Sub phylum Ustilaginomycotina Class Ustilaginomycetes Order Ustilaginales Family Ustilaginaceae Genus Ustilago Species U.tritici (P ers.) SYSTEMIC POSITION

9. PATHOGEN -CHARACTERS Loose smut caused by Ustilago nuda tritici . It is a internally seed borne fungal disease. It cause systemic infection. The chlamydospores of the fungus are pale, olive brown, spherical to oval in shape, about 5-9 micro diameter and are adorned with minute echinulations on the wall.

10. PATHOGEN CHARACTERS They germinate readily in water, each spore producing one four celled germ tube( promycelium ). The promycelial cells fuse and give rise to the germ tubes that enter the ovary through the stigma and become established in the embryo, remaining dormant until seed germination. Its presence is revealed only when the plant matures and a smutted ear emerges.

11. MYCELIUM CHARACTERS The Primary mycelium consists of hyaline, slender, septate hyphae with a single haploid nucleus in each cell. ( Monokaryotic or haplo mycelium). The Secondary mycelium consist of hyphae with two haploid nuclei in each cell. ( Dikaryotic hyphae).

12. MYCELIUM OF LOOSE SMUT www.biologydiscussion.com

13. DISEASE CYCLE www.slideshare.net

14. EPIDEMOLOGY MODE OF SPREAD PRIMARY SPREAD ( D ormant mycelium) It is internally and externally seed borne and is systemic. The fungus is carried over in the seed as dormant mycelium. When the planted seed germinates the mycelium becomes active. It grows along with the plant and when the panicle is produced the mycelium reaches the ovaries and transforms the ovaries into a mass of black smut spores. m the infected heads land on the later emerging florets and infect the frequent rain showers , high humidity and temperature. The disease is internally seed borne, where pathogen infects the embryo in the seed.

15. SECONDARY SPREAD ( Teliospores ) Secondary spread occurs through wind borne smut spores. The sporidia infect the healthy flowers. The mycelium enters the ovary and remains in the seed as dormant mycelium .

16. FAVOURABLE CONDITIONS Cold climate (16 -22°C). Humid weather - 60-85%.

17. MANAGEMENT Treat the seed with Carboxin ( Vitavax ) @ 2g/kg seed before sowing. Grow resistant varieties like Sonalika , Kalyan 227, PV18, WG307, NP13 and C302. Burry the infected ear heads in the soil, so that secondary spread is avoided . Spraying of fungicides like Carboxin ( Vitavax ) 0.125 % or Tebuconazole ( Folicur ) 0.2%.

18. Hot water treatment (Jenson, 1886): Soak the seeds in water @ 26-30°C for 5 hours to induce dormant mycelium to grow. Then immerse the seeds in hot water a @ 54°C ( 129°F ) for 10mins to kill the mycelium. Solar treatment ( Luthra and Sattar , 1954 in Punjab): Soak the seeds in cold water for 4 hours from 6AM to 10AM in the forenoon on a bright sunny day followed by spreading and drying of seeds on brick floor in bright sun ( 44°C ) for 4 hours from 10AM to 5PM in the afternoon.

19. FLAG SMUT SIGNIFICANCE Flag smut caused by Urocystis tritici ( U.agropyri ) was an important disease in Victoria. Flag or stem or stripes smut, of wheat was 1 st observed in South Australia in 1868. Typical loss range in Australia is 5-20%. In India the losses due to flag smut is 3-5%

20. DISTRIBUTION World: Japan, South E ast Asian countries, India, Pakistan, Middle East countries, Europe, South Africa and the U.S.A. India: Haryana, Madhya P radesh , Delhi, Rajasthan and Himachal Pradesh.

21. SYMPTOMS The early symptoms include “Leprous” spots. The symptoms can be seen on stem, culm and leaves from late seedling stage to maturity. The seedling infection leads to twisting and drooping of leaves followed by withering. Grey to greyish black sori occurs on leaf blade and sheath. The sorus contains black powdery mass of spores.

22. Flag smut of wheat www.alamy.com

23. SYSTEMIC POSITION Kingdom Fungi Phylum Basidiomycota Class Ustilagomycetes Order Urocystidales Family Urocystidiaceae Genus Urocystis Species Agropyri ( Preuss ) 1867

24. PATHOGEN -CHARACTERS The pathogen is seed borne as well as soil borne disease. Aggregated spore balls, consisting 1-6 bright globose , brown smooth walled spores. surrounded by a layer of flat sterile cells. Basidiospore germinates to produce primary mycelium.

25. Spore balls www.discoverlife.org

26. DISEASE CYCLE en.wikipedia.org

27. EPIDEMOLOGY MODE OF SPREAD The pathogen is seed borne as well as soil borne disease. Basidiospore germinates to produce primary mycelium. Primary infection occurs by sowing infected seeds or by resting spores present in soil.

28. FAVOURABLE CONDITIONS Temperature of 18-24°C. Relative humidity 65% and above.

29. MANAGEMENT Treat the seeds with brine solution. Use cleaned seeds. Avoid seeds from infected area. Fallow 3 years crop rotation in disease sick plots. Rotation helps to break the cycle of disease. Roughing and burning of infected plants.

30. MANAGEMENT Treat the seeds with carboxin ( Vitavax ) or tebuconazole ( Folicur ) or triadimefon ( Bayleton ) @ 2g /kg. Grow resistant varieties like Pusa 44 and WG 377. Dry seed-dressing with non- systemics such as copper carbonate and systemics such as carboxin , oxycarboxin ( Plantvax ) and pyracarbolid have also been used .

31. REFERENCES Rangaswami , G and Mahadevan , A.2016. Diseases of Crop P lants in India. Rekha Printers Private Limited, New Delhi. Singh, R. S., 2018. Plant Diseases. Scientific International ( Pvt. ) Ltd, New Delhi.