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Ministry of Agriculture, Food and Rural Affairs

Peachtree Borers

PTB larva and damage PTB damage to trunk PTB frass on black knotPeach tree borer malePeach tree borer female
Click to enlarge.

Beginner

This pest affects:

peach apricot plum sweet cherry tart cherry;

Scientific Name
Peach tree borer (PTB) - Synanthedon exitiosa
Lesser peach tree borer (LPTB) – Synanthedon pictipes

Identification
Peach tree borer
Adult

  • Large, clear wing moths with metallic-blue body
  • Males have 3-4 yellow-white bands on abdomen; both pairs of wings are clear with an amber sheen; black scales between the eyes and yellow scales between the antennae; anal tuft at the tip of the abdomen in the shape of an elongated wedge
  • Females are 2.5 cm long with a single, wide orange band on the abdomen; forewings opaque
  • Fly during the day

Larvae

  • Feed mainly near ground level, within 30 cm of soil; attack roots and trunks
  • Newly hatched larva approx 1.5 mm long; fully grown larva is up to 3.1 cm long; white or cream with a brown head
  • Overwinter as 1st to 4th instars under the bark at the base of the tree, usually below ground level

Pupae

  • 19 mm long; light brown
  • Within a cocoon made of silk, gum, and chewed wood fragments

Lesser peach tree borer
Adults

  • Large, clear wing moth; blue-black body, 15-23 mm long; wingspread of 19-30 mm
  • Males and females are similar in appearance; both sexes resemble male peachtree borer moths
  • Males have only 2 yellow bands on abdomen; abdomen ends in a triangular tuft of scales; two white or pale yellow patches of scales below the antennae and in front of the eyes and white outer and black inner scales in a row of scales along the back of the head; white tufts of hair on leg joints

Larvae

  • 0.6 mm when first hatched; 23 mm long at maturity
  • Dull white with a yellowish brown head and 3 pairs of short jointed legs
  • 3 pairs of short legs on the thorax and 4 pairs of prolegs with hook-like crochets on abdominal segments 3, 4, 5, and 6, and on the anal proleg; crochets arranged as two transverse bands
  • Feed in cankers and wounds present on the tree; not limited to lower part of tree

Damage

  • Loose, dead bark and masses of gummy sap mixed with frass exuding from entry and exit holes
  • Bark eventually peels off at damaged areas
  • Leaves on a portion of the tree may turn yellow and wilt. The tree canopy will eventually die back
  • Peach tree borer (PTB) larvae only the lower 30 cm  of the trunk, and usually enter at or just below ground level; prefer healthy young trees;  feeding can completely girdle and kill nursery whips and young trees
  • Older trees may withstand the damage, but will be predisposed to attack by other insects and diseases, and can be killed after several years of infestation
  • Larvae of the lesser peachtree borer (LPTB) are associated with cankers, pruning wounds and winter or insect-injured areas; attack older trees; can be found in scaffold branches and trunk above ground
  • Skins of pupae left attached to the bark of the lower trunk or in the soil near the trunk base, or by a larva and/or larval tunnel under the bark
  • Gummosis and frass may be apparent at the base of the tree where peach tree larvae are actively feeding

Often Confused With
Winter or mechanical injury or fungal pathogens – no frass, larvae or pupae present.

American plum borer - Larvae greyish-green to greyish-purple with yellow head capsule, cervical shield, and anal plate and cervical shield with dark markings on either side; emerged pupal skins of the plum borer do not extrude from the cocoon or from the bark.

Woodpecker damage – holes in trunk are usually in well-defined rows instead of random; no frass associated with injury.

Period of Activity
PTB: July through September.

LPTB: May through September with peak flight from June through July.

Scouting Notes
Examine cankers during pruning for gum and sawdust-like castings or the presence of pupal skins from the previous year.

Pheromone traps are used to monitor the emergence of male moths throughout the season.

Threshold
If most trees show signs of borer activity the recommended sprays should be applied. Timing of sprays relative to flight depends on the product used.

Advanced

This pest affects:

;

Scientific Name
Peach tree borer (PTB) - Synanthedon exitiosa
Lesser peach tree borer (LPTB) – Synanthedon pictipes

Identification
Peach tree borer
Adult

  • Large, clear wing moths with metallic-blue body
  • Males have 3-4 yellow-white bands on abdomenl; both pairs of wings are clear with an amber sheen ; black scales between the eyes and yellow scales between the antennae; anal tuft at the tip of the abdomen in the shape of an elongated wedge
  • Females are 2.5 cm long with a single, wide  orange band on the abdomen; forewings opaque
  • Fly during the day

Larvae

  • Feed mainly near ground level, within 30 cm of soil; attack roots and trunks
  • Newly hatched larva approx 1.5 mm long; fully grown larva is up to 3.1 cm long; white or cream with a brown head
  • Overwinter as 1st to 4th instars under the bark at the base of the tree, usually below ground level

Pupae

  • 19 mm long; light brown
  • Within a cocoon made of silk, gum, and chewed wood fragments

Lesser peach tree borer
Adults

  • Large, clear wing moth; blue-black body, 15-23 mm long; wingspread of 19-30 mm
  • Males and females are similar in appearance; both sexes resemble male peachtree borer moths
  • Males have only 2 yellow bands on abdomen; abdomen ends in a triangular tuft of scales; two white or pale yellow patches of scales below the antennae and in front of the eyes and white outer and black inner scales in a row of scales along the back of the head; white tufts of hair on leg joints

Larvae

  • 0.6 mm when first hatched; 23 mm long at maturity
  • Dull white with a yellowish brown head and 3 pairs of short jointed legs
  • 3 pairs of short legs on the thorax and 4 pairs of prolegs with hook-like crochets on abdominal segments 3, 4, 5, and 6, and on the anal proleg; crochets arranged as two transverse bands
  • Feed in cankers and wounds present on the tree; not limited to lower part of tree

Damage

  • Loose, dead bark and masses of gummy sap mixed with frass exuding from entry and exit holes
  • Bark eventually peels off at damaged areas
  • Leaves on a portion of the tree may turn yellow and wilt. The tree canopy will eventually die back
  • Peach tree borer (PTB) larvae only the lower 30 cm  of the trunk, and usually enter at or just below ground level; prefers healthy young trees;  feeding can completely girdle and kill nursery whips and young trees
  • Older trees may withstand the damage, but will be predisposed to attack by other insects and diseases, and can be killed after several years of infestation
  • Larvae of the lesser peachtree borer (LPTB) are associated with cankers, pruning wounds and winter or insect-injured areas; attacks older trees; can be found in scaffold branches and trunk above ground
  • Skins of pupae left attached to the bark of the lower trunk or in the soil near the trunk base, or by a larva and/or larval tunnel under the bark
  • Gummosis and frass may be apparent at the base of the tree where peach tree larvae are actively feeding

Often Confused With
Winter or mechanical injury or fungal pathogens – no frass, larvae or pupae present

American plum borer - Larvae greyish-green to greyish-purple with yellow head capsule, cervical shield, and anal plate and cervical shield with dark markings on either side; emerged pupal skins of the plum borer do not extrude from the cocoon or from the bark

Shothole borer - numerous exit and entrance holes obvious on the outside of infested limbs give a shothole effect;  below the bark, slender mines, usually at right angles to the maternal gallery, occasionally crisscrossing over one another between the bark and the sapwood; exit burrows from the pupal cells to the outside.  

Woodpecker damage – holes in trunk are usually in well-defined rows instead of random; no frass associated with injury

Biology
All stone fruits in the genus Prunus, which include peach, cherry, plum, prune, nectarine, apricot, and ornamental shrubs are susceptible to damage by the peach tree borer.

Both species overwinter as larvae, completing development the following spring/summer before emerging as adults.  The PTB completes its development in the summer, with adult moths emerging from July through September. Emergence pattern of the LPTB is prolonged and less synchronous, and occurs from late May through September. Peaks occur from June through July.

The peach tree borer is a serious pest only to young trees. Trees protected from peach tree borer the first 4 to 5 years do not usually suffer serious injury. Moths emerge from mid-July to September and egg laying begins soon after emergence. Eggs are laid on the tree trunk or on nearby foliage. The egg stage lasts about 12 days. Larvae feed in the trunk until late fall, are dormant in winter, resume feeding in the spring and pupate in late June or early July. A few larvae may overwinter a second time and require two years to complete their life cycle.

Larvae of the lesser peach tree borer feed in cankers and wounds present on the tree. Larvae do not establish in healthy bark. Although there are up to 3 periods of moth activity, the life cycle is normally completed in one year. Eggs are laid on or near cankers or wounds soon after moth emergence. The larvae hatch 10 to 14 days later and penetrate into the damaged or diseased tissues. Feeding is accompanied by exudation of castings and gum. Feeding ceases during winter and resumes in spring. Larvae pupate from May to August.

Period of Activity
PTB: July through September.

LPTB: May through September with peak flight from June through July.

Scouting Notes
Examine cankers during pruning for gum and sawdust-like castings or the presence of pupal skins from the previous year.

Pheromone traps are used to monitor the emergence of male moths throughout the season.

Threshold
If most trees show signs of borer activity the recommended sprays should be applied. Timing of sprays relative to flight depends on the product used.

Management Notes
OFM sprays fall within period of LPTB activity. Pyrethroid based materials applied at OFM rates will provide only moderate residual control of borers and should not be relied on for control if borers have been a problem in the past.

The standard practice of growers dropping spray nozzles to cover trunks has replaced routine LPTB trunk only sprays. However, air blast sprayer application of pesticides is not very effective for borer control. Hand-gun applications give better coverage of trunks and lower scaffold limbs but are labour intensive.

Mating disruption technology for borers is available and considered very effective in other jurisdictions when used over large areas and where populations are low.  See OMAFRA Publication 360, Fruit Crop Protection Guide.

Chapter 5 - Peach Calendar:  Recommendations for PTB and LPTB at shuck split to shuck fall.
Chapter 5 - Plum calendar: Recommendations for PTB and LPTB at shuck fall.

Management with insecticides:  Insecticides are used to control peachtree borer and lesser peachtree borer in commercial orchards with a history of damage.  See OMAFRA Publication 360, Fruit Crop Protection Guide.

Chapter 5 - Peach Calendar :  Recommendations for PTB and LPTB at shuck split to shuck fall
Chapter 5 - Apricot Calendar : Recommendations for PTB and LPTB at shuck fall.
Chapter 5 - Plum Calendar: Recommendations for PTB and LPTB at shuck fall.
Chapter 5 - Sour Cherry Calendar: Recommendations for PTB and LPTB at special sprays.

Some information included above excerpted from;