Peach Twig Borer

Anarsia lineatella, Peach twig borer


Peach twig borer, Anarsia lineatella is a serious pest of stone fruits. The main host crops are peach, apricot, nectarine, almond, plum and prune. Young larvae bore into buds and developing shoots causing them to wilt and die. When populations are high, spring larval feeding can cause substantial damage to trees. Larvae of the summer generations attack the fruit, usually making several entry holes near the stem end. Damaged fruit and twigs exude gum.

OVERVIEW

Adult moths are small 0.3-0.5 inches long, with light and dark grey mottled wings. There are scales on the front of the head giving it a pointed appearance.  Each female can lay 80-90 eggs. Eggs are deposited singly on young and tender shoots, undersides of leaves and on developing fruits. Eggs are yellowish white to orange and oval shaped. Egg hatching occurs in 4-18 days depending on temperature.

Young larvae are pale with light brown rings and a black head. Older larvae are chocolate brown with a dark brown head and prothorax. Mature larvae are roughly 0.5 inches long and pupate in 2-3 weeks. First and second instar larvae overwinter in silken cells called hibernacula.

Pupae are brown in colour and smooth in appearance with no cocoon. The pupae from overwintering larvae can take up to 30 days to mature in cool spring temperatures. Pupation stage for summer generations is 7-11 days.