Peach twig borer, Anarsia lineatella

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.

Biology

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.

Nature of Damage

 Peach twig borer, Anarsia lineatella larvae are firstly attracted to new shoot growth of the tree and secondly to maturing stone fruits. Larvae of early generations feed inside the terminal shoots, causing the leaves to wilt which leads to the death of the terminals. On young trees especially, repeated attack of the terminal branches can cause stunted tree growth.

As the fruit pits harden and the fruit develops in colour the maturing fruits become more appealing to the larvae, which enter primarily through the stem and feed just underneath the skin or next to the pit.  Older larval generations attack the fruit, usually making several entry holes near the stem end. Damaged fruit exude gum. Once the larvae have completed there development inside the fruit, small, sticky exit holes may be visible, which then attract other insects i.e. earwigs to enter the fruit through the tunnels that the peach twig borer created.

Monitoring

Russell IPM manufactures and supplies pheromone lure – the Qlure, traps and complete monitoring systems for Leek moth, Acrolepiopsis assectella, also known as onion moth.

Pheromone trap data gives early warning of the infestation and will also alert the user to a low level of population before it becomes serious.

The lure can be best applied with the Mothcatcher trap or Delta trap.

Application Guidelines

Russell IPM manufactures and supplies pheromone lures, traps and complete monitoring systems for Pear twig borer, Anarsia lineatella. The Qlure pheromone trap data give early warning of the infestation and also will alert the user to low level of populations before they become serious

Pheremones

The following notes are guidelines of general nature and meant to give the user a head start in implementing pheromone monitoring programme. Local conditions and practices can vary and can lead to customisation of the programme.

Trap Selection

The Deltra trap is the most sensitive trap to use for monitoring this insect. However, Moth catcher may be used in dusty conditions or in high moth population density. Do not re-use the trap to monitor different insects as this may lead to mixed catches.

Trap Density

For monitoring, use two traps per hectare ( 2 traps / ha) for small holdings and in field of uneven topography. One trap for every two hectares of large scale fields of homogenous lands.

Trap data and interpretation

Collect data weekly from the start of the flight of the over wintering generation. During the height of the population a more frequent reading may be needed. Decisions on pesticide application should not be taken solely on the trap catch data. Climatic and biological considerations should be taken in account.

Lures

Lures can be changed every 4-6 weeks to get the most accurate results.

Lures Handling

Pheromone lures are a very sensitive tool. They can be affected by exposure to elevated heat and direct sunshine. Direct touching by hand may cause cross contamination leading to mixed catches in the trap. Some contaminants such as Nicotine may have repellent effect reducing trap catch.

Lure Storage

Store in a cool dry place.

Shelf life can vary from 3-36 months depending on the storage temperature.

See Technical Data Sheet for further details.