• Y S Rao

      Articles written in Proceedings – Animal Sciences

    • Cultural control of rice root nematodes (Hirschmanniella spp.) withSphenoclea zeylanica

      C Mohandas Y S Rao S C Sahu

      More Details Abstract Fulltext PDF

      Sphenoclea zeylanica, a non-host of rice root nematodes,Hirschmanniella spp., was found to control them to 95% within 6 weeks and 99% within 8 weeks in a heavily infested field. Water extracts of shoot and the entire plant at highest concentration were toxic toHirschmanniella oryzae at 48 hr exposure whereas that of root were not toxic. But whenH oryzae were picked into a tube where the plant was grown hydroponically, 95% of the nematodes were killed at 60 hr exposure.

    • Life history and behaviour of the cyst nematode,Heterodera oryzicola Rao and Jayaprakash, 1978 in Rice (Oryza sativa L.)

      A Jayaprakash Y S Rao

      More Details Abstract Fulltext PDF

      The embryonic development of the cyst nematode,Heterodera oryzicola and its emergence from egg misses was completed within 8 to 9 days. The emerged second stage juveniles were attracted to roots of rice within 24 hr and penetrated the roots within 24 hr. After penetration, the endoparasitic juveniles developed into males within 14 days and white females within 20 days. Orientation of females was equal towards hypocotyl (42%) and root tip (48%) while a few (10%) matured vertically in thin secondary roots or small rootlets. The sex-ratio between males and females was about 1:4. The virgin females secreted a strong male attractant and the males migrated towards the females in response to this stimulus and mated with the females. The eggs were laid in gelatinous matrix secreted by the females within 22 days and the females turned into brown cysts by 24 days. A singleH. oryzicola female laid on an average 198 eggs in an egg mass and retained 120 eggs within the body of the brown cyst. None of the females was left unmated and all of them laid a single egg mass each within 30 days. One life cycle was completed in 30 days and 12 generations occurred in a year.


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