Stem Fly

Stem Fly: Melanagromyza sojae

Symptoms of damage

  • The eggs are laid on leaves.
  • After hatching from the egg yellowish maggots bore the nearest vein of the leaf.
  • The maggot then reaches the stem through petiole and bore down the stem.
  • If the infected stem is opened by splitting, the distinct zig zag reddish tunnel can be seen with maggot or pupae inside it.
  • The maggots feed on cortical layers of the stem, may extend to tap root, killing of the plant.

Identification of the pest

  • Maggot: White in colour and remains inside the stem.
  • Adult:  Flies are shining black and about 2 mm long.


  • Deep summer ploughing.
  • Avoid pre-monsoon sowing.
  • Use optimum seed rate and plant spacing.
  • Proper crop rotation with dissimilar crops should be followed.
  • Remove and destroy the damaged plant parts.
  • Soil application of phorate 10 G @ 10 kg/ha or carbofuran 3 G @ 30 kg/ha at the time of sowing will prevent early infestation by stem fly.
  • One or two sprays of 0.03% dimethoate 30 EC or 0.05% quinalphos 25 EC can stop the damage.



  • TamiNadu Agritech Portal


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