concentric brown spots

Basil    Morocco

Disease in basil which produces this type of patches?

Posted by: Sara (1 point) Sara
Posted: December 26, 2017


It could be a leaf spot disease caused by Colletotrichum sp. The main symptoms are the initial appearance of white colored circular spots, which later coalesced and resulted in necrosis of leaves. In the severe case, it may cause defoliation, tip dieback, stem lesions, and sometimes death of the whole plant.

The pathogen is favored by high humidity. The spores transmit from one plant to another by water splashing.


Posted by: Dr. Ravishankar Narayana (15 points) Dr. Ravishankar Narayana
Posted: December 26, 2017

Mr Ye Aung commented,
i think that this symptom is Alternaria Leaf Blight
over 6 years ago.

Hi Sara,

Due to the concentric rings pattern of the lesion, the problem definitely seems fungal. I think the pathogen might be Leaf Spot (Cercospora ocimicola). You can find out more about it here on the PlantVillage website.

To manage the disease pick off the affected leaves while being careful not to touch any uninfected leaves. Also, water at the base of the plant and be cautious not to have the water splash back up, this will spread the fungus.

Posted by: Kelsee Baranowski (6 points) Kelsee Baranowski
Posted: January 16, 2018

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