🪱 Ditylenchus Nematodes

Species, Biology, Symptoms, Integrated Management

Which of the following is not wrong regarding Ditylenchus nematodes?

Rice Stem Nematode

  • Butler first reported Ditylenchus angustus in 1913 form East Bengal region (Now Bangladesh) as the casual organism of Ufra disease of rice.
  • Butler named this disease in the honour of his assistant Uftar Rahman, who first brought the diseased specimens to him.
  • In India, the rice stem nematode is prevalent in the eastern states of Assam, West Bengal, Bihar and parts of Uttar Pradesh.
  • Rice is the main host.
  • It is an ectoparasite of above plant-parts.
  • The pre-adult stage (fourth stage juveniles J4) forms cottony masses (nema wool) as the nematodes enter quiescent phase when the crop matures.
  • Infestation mainly in deep water paddy.

Symptoms

  • The first symptoms appear when the crops is 2-3 months old in the form of chlorosis and yellow streaks on the upper leaves.
  • The symptoms of Ufra are well noticed in two months old crops.
  • Later two types of symptoms are manifested:
    • Swollen Ufra in which case the panicles fail to emerge, and the stalks show a tendency to branch.
    • Ripe Ufra when panicles emerge but are distorted and sterile.
  • Twisting of leaf & leaf sheath.

Stem and bulb nematode

  • Ditylenchus dipsaci is a serious problem of bulbous ornamental plants and other crops like onion, garlic, alfalfa, celery, oats, rye etc. in temperate areas of the world.
  • Stem and bulb nematode undergoes quiescence and forms nema wool in which condition it can survive for as many as 23 years.
  • By infestation of this nematode onion suffers heavy losses as it causes “onion bloat” disease.

Potato rot nematode

  • Ditylenchus destructor
  • It is prevalent in temperate region of Europe & North America
  • Cause root rots on potato tubers.

Mushroom Nematode

  • Ditylenchus myceliophagus
  • Mycophagous nematode feed on fungal mycelium.
  • This nematode was first reported that to cause damage on mushroom.
  • It is also found in India.
  • It is found with Aphelenchoides composticola.
References 
- Dropkin, V.H. 1980. Introduction to plant nematology. John Wiley and sons, INC. New York.
- Singh, R.S and Sitaramaiah, K. 1994. Plant pathogens. The plant parasitic nematodes. Oxford & IBH Pub. Co. Pvt. Ltd. New Delhi.
- Parvata Reddy, P. 1983. Plant nematology. Agricole Pub. Co., New Delhi.
- Southey, J. F. Laboratory methods for work with plant and soil nematodes Tech.
- Bull. Min. Agric. Fish. Food. Her Majesty’s Stationary Office, London.
- Walia, R. K and Bajaj, H. K (2014). Textbook of Introductory Plant Nematology. Directorate of Knowledge Management in Agriculture, ICAR, New Delhi. 
- Kumar, V., Khan, M.R. & Walia, R.K. Crop Loss Estimations due to Plant-Parasitic Nematodes in Major Crops in India. Natl. Acad. Sci. Lett. 43, 409–412 (2020). https://doi.org/10.1007/s40009-020-00895-2

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