Horse-chestnut leaf miner
lower parenchyma. The mine starts to turn yellow and later brown. By this time, the damage is very visible. Eventually the mines may cover the entire surface [...] develop a round mine of 4-7 mm diameter. The larva then goes through two spinning instars, which may or may not build a true cocoon in the mine. The percentage [...] greatly affected, but when the entire surface of leaves is covered with mines, the leaves start to dry out and fall off. However, total defoliation does