• Small, round to irregular spots with grey centre and dark margin on leaves.
• Spots coalesce and leaves are blighted.
• Complete defoliation.
• Stems and flowers are affected.

Irregular spots on leaves

Leaf spots

Causal Organism – Septoria lycopersici Speg.

Mycelium : Hyaline and septate

Fruiting body : Pycnidium: globose, without distinct ostiole

Pathogen: Pycnidiospore : filiform, septate, hyaline

Survival and Mode of Spread

Survival: Infected plant debris

Primary spread: Mycelium or conidia

Secondary spread: Conidia through rain splash or wind

Favourable conditions

• High humidity .

Integrated Disease Management

Cultural:

• Removal and destruction of affected plant parts

Biological :

• Seed treatment :Trichoderma asperellum @ 4g/kg seeds

Chemical:

• Fluxapyroxad 250 g/l + Pyraclostrobin 250 g/l SC - 200-250 ml/ha.

Source of Information:

• Crop production guide – Horticulture 2020.

Acknowledgement:

• Dr.N. Indra, Associate Professor, Department of Plant Pathology, TNAU, Coimbatore.
• Dr.P.Renukadevi, Professor, Department of Plant Pathology, TNAU, Coimbatore.
• Photo courtesy Dr.S.Vinodkumar.