The trumpet apple leafminer, Tischeria malifoliella Clem., is a small moth, the larva of which constructs a mine or cell beneath the upper epidermis of the leaf. The characteristic trumpet-shaped appearance of the larval mine has given this insect its common name.
It feeds upon different species of Malus, including all varieties of apple, and also Crataegus or wild haw, and with its increase as a pest becomes a serious menace to profitable apple production. In severe cases of infestation, the leaf may support as many as 68 larvae, the feeding tunnels of which combine in one large irregular blotch mine involving and killing a large portion of the leaf or even the entire leaf. Defoliation may then result, followed by premature, undersized fruit and a lessened vitality of the tree.
Dunnam, E. W.
"The Apple Trumpet Leafminer,"
Bulletin: Vol. 18
, Article 1.
Available at: https://lib.dr.iastate.edu/bulletin/vol18/iss220/1