IFS (Forest Services) Agriculture: Questions 1 of 646

Appeared in Year: 2015

Describe in Detail Subjective▾

Write short notes on the following: Tundu disease of wheat (Paper-1, Section-A)

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Explanation

Tundu Disease of Wheat

  • Tundu disease of wheat is also called as yellow Ear rot or Ear cockle.
  • Tundu is a minor disease problem worldwide.
  • It is quite common in north-west regions of India.
  • This disease of wheat was first reported by Hutchinson in 1917 from Punjab.
  • Now it is spread in many other parts of the country like Haryana, U. P. , Rajasthan, M. P. and Bihar.
  • This disease is also common in Canada, China, Australia and Egypt.

Pathogen or Causal Organism

  • Tundu disease is caused by bacterium Corynebacterium tritici.
  • It is gram-positive bacteria, rod shaped with single polar flagellum.
  • Tundu disease is actually caused by the combined action of bacterium Corynebacterium tritici and nematode Anguina tritici.
  • The galls in the ear heads are formed by the nematodes and these galls carry the bacterium.

Symptoms

  • The early symptoms include twisting of stem and distortion of spikelets or ear heads.
  • Yellow exudate on the spikes is indicative of bacterial diseases.
  • When it is dry, the exudate is white to yellow white.
  • The spikes and necks will emerge as a distorted sticky.
  • The early leaves may also be wrinkled or twisted.
  • Most of the grains in the ear heads are replaced by galls and these galls contain the causal bacterium Corynebacterium tritici.

Spread

  • Seeds are contaminated with nematode galls which are responsible for the spread of the disease.

How to Control

  • Use of seeds which are free from nematode galls or use certified seeds.
  • Nematode galls can be removed by sieving or flotation in 5% salt solution and washing thoroughly in plain water and drying the seed before sowing.
  • Hot-water treatment of contaminated wheat seed is also effective in the removal of nematode galls from seed lots.
  • In 1938, Jones et al. developed an indented cylinder machine which separated oval wheat seeds from globular nematode galls and this device was claimed to be 98% effective in removing seed galls.
  • In 1945, Chu also designed a machine to separate nematode galls from healthy grain.

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