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Are Nematodes a Problem in SRI?

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Are Nematodes a Problem in SRI? . J.S. Prasad, Ch. Padmavathi, R.M. Kumar, and L.V.Subba Rao. Directorate of Rice Research, Rajendranagar, Hyderabad-500 030. INTRODUCTION.

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slide1

Are Nematodes a Problem in SRI?

J.S. Prasad, Ch. Padmavathi,

R.M. Kumar, and L.V.Subba Rao

Directorate of Rice Research,

Rajendranagar, Hyderabad-500 030

slide2

INTRODUCTION

  • High yields of rice declined in Brazil and China after 3-4 years under aerobic conditions, possibly due to nematodes or toxic substances (Bouman, 2002).
  • Yield differences between aerobic and flooded rice ranged from 8 to 69%, the differences attributed to the build-up of nematodes (Peng et al., 2006).
  • Under controlled irrigation, even small pest problems have great impacts on yields and farmers\' income.
slide3

Nematode pests that could be associated with SRI

Uncontrolled irrigation can be associated with the rice root nematode

Hirschmanniella spp. – yield loss 8-23% (Kuriyan and Sheela, 1981)

slide4

Controlled irrigation can be associated with the root-knot nematode Meloidogyne graminicola -- yield loss 21-64 % (Rao and Biswas, 1973)

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Materials and methods

Field Experiment – Split Plot

Treatments: SRI, Eco-SRI, and Conventional

Varieties: Rasi and Jaya

  • Greenhouse studies
  • Treatments:
  • Continuous flooding
  • Optimum moisture (OM)
  • Flooding & OM alternated at weekly intervals
slide11

Incidence of root-knot nematode at various moisture levels

Figures in parentheses indicate √X+0.5 transformed values

conclusions
CONCLUSIONS
  • Under aerobic or saturated conditions, more gall formation on the roots by root-knot nematode was observed
  • In conventional rice cultivation, H. oryzae population is more
  • In SRI fields where no water control is possible, there is need to monitor for the root nematode H. oryzae
  • Existing root knot nematode infection may not express itself, but when aerobic conditions prevail, symptoms do appear
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Possible impact of SRI cultivation on plant parasitic nematodes

  • Use of cono-weeder would destroy the nematodes that have invaded the roots of weed plants
  • The incorporation of weeds and organic nutrients deters movement, migration and infestation by nematode pests
  • Decomposing organic matter promotes beneficial predatory and saprophytic nematode populations
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