The peach twig borer, Anarsia lineatella, is a pest of peach and also attacks apricots and almonds. It occurs in Europe, North Africa, North America, and Asia.
Life cycle and appearance of Peach twig borer
The moths have a wingspan of 12-16 mm, with dark brown to greyish black forewings with irregular black markings, and light brownish grey hindwings. The eggs are elongate-oval, about 0.3 x 0.5 mm in size and orange yellow. The larvae are up to 16 mm long with a dark brown to reddish brown body, paler between the segments. The head is black. The pupae are 6-8 mm long and dark brown.
The first generation adults usually appear in May and early June and those of the second generation in late July and August. Eggs are laid on the base of leaves and hatch after about 2 weeks. The larvae bore into the young shoots. They move from one shoot to another and can damage several shoots during the course of their development. The larvae may also attack the fruits where they tunnel through the flesh and bore into the stone. Fully grown larvae pupate in a silken cocoon. Second generation larvae can be found in August and September. They hibernate as larvae in a silken cocoon under the bark of host trees and complete their development by spring feeding on the blossom and also boring into young shoots. In warmer climates there can be three or four generations.
The tips of attacked shoots wither and die but this is generally only a problem in nurseries and young orchards. Infested fruits develop large necrotic areas and become distorted. Attacked apricots exude large quantities of gum. Attacks on fruits can cause significant yield loss.