• The damage caused by single larva is minimal.
• However,when large populations are present they are capable of destroying leaves affecting growth of plants.
• The larvae of the fly remaining inside the leaf mine feed on the contents.
• The damage causes tightly coiled almost blotch like mines.
• The mined portion of the leaves later dries affecting the photosynthetic capacity of the affected plants.

Select 10 leaves each ( at random) from ten plants and assess the percentage of damage and workout the average per plant.Less than 5% mild 5-10% moderate; more than 10% severe.