• Water soaked spots appear on the lower surface of leaf.
  • Later these become more or less circular in outline and show definite brown coloured margins with grey centre (Plate-4).
  • A few black glistening pinhead sized pycnidia may be seen in the center of spots.
  • On stem, disease appears as small, slightly elongated, dark spots containing numerous black pycnidia.
  • Black circular spots may also be seen on young as well as mature fruits.


  • The disease is incited by Septoria lycopersici Speg.
  • On the host, young mycelium is hyaline, thin walled and sparingly septate.
  • Pycnidia are subglobose, composed of 2-3 layers of brown cells.
  • Pycnidiospores are filiform, slightly curved, hyaline and septate with pointed or rounded ends. No sexual stage has been reported.
  • Two physiologic races have been identified.
Disease cycle and Epidemiology:
  • The pathogen overwinters in infected plant debris in the form of mycelium or conidia or in debris of solanaceous weed hosts, such as horsenettle (Solanum carolinense L.) (Fig. 3.).
  • The conidia are splashed by rain to the lower leaves of the plants.
  • The spores produced in these pycnidia continue the secondary cycle of this disease.
  • Temperature of 20-25oC with 75-92 per cent relative humidity is congenial for disease development.


  • Destruct infected plant debris and use of clean seed.
  • One to two years crop rotation, trimming of lower leaves and staking of plants in case of indeterminate varieties/ hybrids have been found useful.
  • With the initiation of the disease, spray the crop with carbendazim (0.1%) or mancozeb (0.25%) and repeat at 10 to 14 days interval.
Last modified: Monday, 12 March 2012, 6:05 AM