A Each female lays about 30 eggs singly in the opening flowers. Sap seeps out of the wound made by the female when laying her eggs. It turns red/brown and can be a good early warning of an attack. A larva hatches after two weeks and burrows into the fruitlet, usually at the eye, aiming for the pips on which it feeds. Once under the skin of the fruitlet it tunnels in the surface layer before it burrows into the core. If it does not reach the core it still causes superficial damage which results in the characteristic curved scars. It tunnels out an area of the fruit, filling it with wet brown droppings or frass. Larvae may move on and attack two or three apples, and sometimes more than one grub is found in a single fruit. Often the fruitlets attacked later have masses of frass at the eye where the entry hole was made. After two weeks' feeding, the larvae leave the fruit to overwinter in the soil.