Tundu disease. Diseases of wheat and management 2019-02-21
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diseases of wheat
They are readily seen in the electron microscope and are usually transmitted by leaf hopper. Stubby-root nematodes: Paratrichodorus minor Colbran Siddiqi Paratrichodorus spp. On maturity it ruptures and millions of tiny black smut spores teliospores are liberated and disseminated by the wind. Sprague Arx; Gloeosporium bolleyi R. Mode of Spread and Survival: The pathogen survives as dormant mycelium in the seed or as conidia on the surface of seed for about a year. Conidiophores may arise singly or in small groups.
Loss of chlorophyll of new leaves. The spores and sporidia are also present in the infected plant materials in the soil. Favourable Conditions: Prolonged rainy weather at flowering and damages caused by insects and caterpillars. Transmission by mechanical means: Many viral diseases especially mosaic viruses are mechanically transmitted by the following methods: a By contact of infected leaves with healthy leaves brought about by wind. Stem rot: Sclerotium oryzae Symptoms: Small black lesions are formed on the outer leaf sheath and they enlarge and reach the inner leaf sheath also. Finally the whole finger is affected.
IFS (Forests Services) Botany (Mains) Microbiology and Plant Pathology Questions 1 to 10
Avoidance of vectors: a Breaking the life cycle of hosts, vectors and viruses b Creating physical barriers c Early sowing d Crop rotation e Intercropping 3. . Favourable Conditions: Closer planting, high doses of nitrogen, high humidity and temperature around 25-30 °C. The pathogen is seed-borne and it serves as primary source of infection. Seeds free from nematode galls should be sown in nematode free drained field. In a survey of grain markets in Haryana, India, 34.
Mode of Spread and Survival: The pathogen survives as uredospores on groundnut plant. Crop rotation, proper drainage and tuber treatment with0. Spots on petioles and leaves cause them to curl or become distorted. Favourable Conditions Dry weather following heavy rains, high soil temperature 35-39 °C , low soil moisture 15-20 % Mode of Spread and Survival: The disease is mainly soil-borne and the pathogen can survive in the soil as sclerotia for several years. Soil- borne conidia cause disease carry over from season to season. Sugarcane Saccharum officinarum : Red rot: Colletotrichum falcatum Symptoms: Typical symptoms of red rot are observed in the intemodes of a stalk by splitting it longitudinally. Carbendazim 1 kg from 45 day at 15 days interval.
Adjust the sowing time, early sowing First week of April or late sowing Last week of June so that crop escapes the high soil temperature conditions. Epidemiology Disease is severe in old and dense orchards where light intensity is low. The major vector is banana aphid viz. Avoid excess dose of nitrogenous fertilizers. Brown or dark circular or irregular spots are formed on the leaves and such leaves are crinkled.
The primary infection starts mainly from the seed-borne bacterium. Sparying of crop with Metasystox 0. The wood below is stained reddish brown. Among them the canker phase is the most destructive. Adam; Podosporiella verticillata O'Gara; Pyrenophora horrida Syd.
The bacterium appears unable to cause the disease without the nematode. When several spots coalesce, the entire leaf surface may be covered with powdery coating. Favourable Conditions: High relative humidity 96-97 per cent , high temperature 30-32 °C , closer planting and heavy doses of nitrogenous fertilizers. Apply heavy doses of green leaf manure or farm yard manure. The seed is then rinsed and dried. The infection spreads to the green twigs and forms dark brown lesions on them.
When the spots coalesce to form big patches, premature defoliation occurs. Favourable Conditions: Cool temperature and high relative humidity. Conidia are produced in clusters on long septate, olivaceous slender conidiophores. C Downy Mildew plant disease is caused due to prolonged wetness. The disease appears in August It is severe in alkaline soils.
Mode of Spread and Survival: The infected seeds are the most common source of primary infection. Nematode occurs throughout the world and is easily disseminated in seed. Management: Remove and burn the infected plant debris and bolls in the soil. Tilletia aegilopis Golovin; Tilletia brevifaciens G. The head finally withers and droops down with heavy fungal mycelial nets. P … 259 more words … View Full Answer! Smut sopres are viable for more than 10 years. Powdery mildew: Erysiphe cichoracearum Symptoms: Initially greyish-white powdery growth appears on the upper surface of leaves.
Management: Remove and destroy the weed hosts in the field bunds and channels. Grossy shoot of sugarcane C. Initially these stripes are pale yellow in colour, later turn to brown. Imai Spot blotch Bipolaris sorokiniana Sacc. In moist weather, acervuli are produced in abundance on dead twigs and pinkish spore masses are seen. The fungus primarily spreads through infected seeds which carry sclerotia and pycnidia.
