This power point is related to disease of cumbu-pearlmillet-bajra Downy mildew and ergot
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DOWNY MILDEW AND ERGOT OF CUMBU COURSE TEACHER: Dr. PARTHASARATHY S Asst. Professor (Plant Pathology) STUDENT: Mr. KALIRAJ G ID. NO. 2016021016 COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore3 ) Kullapuram (Po), ViaVaigai Dam, Theni-625 562
Common name: Pearl millet Scientific name: Pennisetum glaucum Family: Poaceae
DOWNY MILDEW
SIGNIFICANCE OF THE DISEASE It is also known as green ear disease It was first reported by Butler in 1907
ECONOMIC LOSS It will cause 30% of yield loss in India During 1975, it caused 100% of yield loss in Karnataka and Maharashtra
DISTRIBUTION It is widely distributed in temperate and tropical areas of world It is occurs in India, Iran, Israel, China, Japan, USA and many African countries In India it is occurs in Rajasthan, Gujarat, Maharastra and Uttar Pradesh
DOWNY MILDEW STAGE Infected leaves showing chlorotic streaks on their upper surface Opposite to the streaks fine downy growth on the lower surface In advance stages, the infected leaves become distorted and wrinkled
GREEN EAR STAGE The whole or part of the inflorescence is transformed into twisted leafy structures This imparts the ear an appearance of green leafy mass so it is called as green ear The transformation of floral parts is due to hypertrophy and hyperplasia of the concerned tissue
CAUSAL ORGANISM Kingdom: Stramenophila ( Chromista ) Phylum : Oomycota Class : Oomycetes Order : Scleroporales Family : Scleroporaceae Genus : Sclerospora Species : graminicola Author : ( Saccardo ) J. Schroter
PATHOGEN CHARACTER It is an obligate parasite Hyphae : Coenocytic , intercellular Haustoria : small bulbous haustoria inside the host cells to obtain nutrients Asexual stage – Sporangiophore Sexual stage – Oospore
SURVIVAL It is a soil borne disease Oospores are abundantly present in the diseased leaves during summer season It can survive from eight months to ten years
SPREAD Primary infection by Oospores present in soil and infect the plant Secondary infection by Zoospores present in infected plant Sporangia are disseminated by wind, water and insects
FAVOURABLE CONDITIONS RH above 75% favours the disease Temperature about 15-25 ͦ C favours the disease Disease occurs in July, August and September
MANAGEMENT Cultural method Chemical method Resistant Varieties
CULTURAL METHOD Crop sanitation Early Sowing Transplanting of Pearl millet Roguing
CHEMICAL METHOD Seed treatment with Metalaxyl 35% at 6g per kg of seeds Spray Ridomil 0.1% 20 days after plantation
SIGNIFICANCE It was first reported from South India It is epidemic form was first reported in Maharashtra- 1956 It contain toxic alkaloid – Ergotoxin
ECONOMIC IMPORTANCE Average incidence of the disease is 62% It cause grain loss of about 58% HB-1 and HB-2 are more susceptible
DISTRIBUTION It is distributed in India, Pakistan and several African countries like Nigeria, Somalia, Uganda, Zambia and Zimbabwe In India it is distributed in Delhi, Uttar Pradesh, Rajasthan, Maharashtra, Karnataka, Tamil Nadu, Andhra Pradesh and Haryana
SYMPTOMS Small droplets of pinkish or light honey-coloured fluid exuding from the spikelets Later the droplets become darker, coalesce and cover larger areas of the cob Advanced stages, small dark brown sclerotia projecting between two glumes It contain the Ergotoxin
CAUSAL ORGANISM Kingdom: Fungi Phylum : Ascomycota Order : Hypocreales Family : Clavicipitaceae Genus : Claviceps Species : fusiformis Author : Loveless
PATHOGEN CHARACTER Vegetative stage Honey dew stage
VEGETATIVE STAGE – ASEXUAL STAGE Macroconidia : Hyaline, fusiform and unicellular It will germinate by producing germ tubes Microconidia : Globular, hyaline and unicellular
HONEY DEW STAGE – SEXUAL STAGE Sclerotia is produced It is elongated to round, light to dark brown Sclerotia produce perithecium Perithecium will release ascospores
SURVIVAL The conidia are viable for 13 months The conidia are abundantly present on the sclerotial structures
SPREAD Primary infection by Sclerotia present in the soil Sclerotia will germinate and produce perithecia Perithecia contain 8 ascospores Perithecia will burst and the ascospores infect the plant Secondary infection is insect borne
FAVOURABLE CONDITIONS High RH (85-95%) during flowering Cloudy weather, low sunshine and daily night showers favours the disease Temperature about 20-25ͦ C favours the disease
MANAGEMENT Resistant varieties Cultural method Chemical method
RESISTANT VARIETIES WC-C75 ICMS 7703 ICMV 155
CULTURAL METHOD Adopt long crop rotation programme Use of clean seeds – Seeds are soaked in 20-30% salt solution Repeated ploughing reduce the viability of sclerotia in soil Removal of collateral host – Cenchrus ciliaris , Cenchrus setigerus and Panicum antidotale
CHEMICAL METHOD Seed treatment with captan @ 4g per kg of seed Spray combination of Acibenzolar - S -methyl (0.05 kg a.i ./ha) and Mancozeb (1.5 kg a.i ./ha)