Codling Moth

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Beginner

This pest affects:

Scientific Name
Cydia pomonella

Identification
Eggs:

Laid individually
Flat, elliptical
Almost transparent
1-2 mm in diameter
Rarely seen on fruit

Larvae:

5 larval instars
2-3 mm long, pale creamy white with a black head capsule when newly emerged
12-20 mm in length, cream or pink with a brown or black head at maturity

Pupae:

Brown
10-12 mm long
Found within silken cocoon on trunks or large branches

Adults:

9-12 mm long
Wingspan of 19 mm
Greyish brown with alternating bands of grey and white
Tips of the forewings are bronzed
Mainly active at dusk

Damage:

Small “stings” on the fruit surface
Interior breakdown of tissue caused by tunneling into fruit
Entry/exit holes can occur on the side or bottom of the fruit and is often plugged with brown, sawdust like, frass
Fruit with extensive tunneling often abort prematurely
Fruit with surface feeding may remain on the tree until harvest

Often Confused With

Oriental fruit moth- Oriental fruit moth larvae have an anal comb (absent in codling moth) and when mature are about half the size of codling moth larvae. Feed only on the fruit flesh, not typically found feeding on seeds or around the core

Plum curculio - larvae are legless, white, grub-like (slightly curved, C-shaped) and no clearly defined entry hole or frass present

Lesser appleworm - larvae also have an anal comb and are pinkish in colour; prefer apples, cherries and plums and are only occasionally found in pears. Specialists may be able to distinguish lesser appleworm larvae from OFM larvae and when uncertain, will rear the insects to adults for definitive identification

Period of Activity
Injury to pears caused by codling moth occurs during second or partial third generation as fruit start to soften during ripening.

Adult moths from the overwintering pupae emerge from bloom through to mid June. First generation larvae are present from mid June to mid July. Second generation larvae begin to emerge from late July to mid August and the second generation adult moths appear in early to mid August and flight can continue until late September.

Scouting Notes
Place pheromone traps (diamond trap baited with a pheromone lure) in each orchard (4 traps in each 4 ha block) prior to bloom to establish biofix. Proper trap placement is essential to monitor codling moth populations. Place traps in mid canopy for orchards not using pheromone disruption, and in the top third of the canopy for orchards receiving mating disruption. Place traps on the north side of the tree, 30-50 m apart, in the portion of the orchard most likely to be entered by wild hosts such as areas near woodlots or near abandoned/poorly sprayed orchards. Remove leaves and branches from a 30 cm area around each trap. Change lures and traps every 6 weeks and remove in September.

Monitor pheromone traps twice weekly and record male moth trap catches. Pheromone trap counts are not necessarily an indication of the potential damage from the insect. Trap captures determine first sustained moth catch (biofix) and this information is used in conjunction with a degree-day model, to predict the development of the insect i.e. when eggs are hatching. Although regional consultant reports provide useful information on when this pest is present in an area, growers are encouraged to place traps in each orchard, since pest emergence and pressure varies from orchard to orchard.

Individual orchards, even though geographically close, can have very different pest pressures, so orchards need to be evaluated separately. If you suspect a problem, collect a good sized sample of damaged fruit (30 - 50 or more). Look for obvious signs of insect damage such as entry or exit holes and "frass" on the fruit when sampling in the orchard. Sample fruit that have ripened early, including any in storage that ripen earlier than most. Early ripening is not a diagnostic feature of any particular insect damage; premature ripening will occur with infestation by any pest.

Thresholds
Thresholds for codling moth are based on a degree-day model. The accumulation of these degree-days is initiated by the biofix. The timing of insecticide applications relative to growth stage of the insect is different depending on the way the insecticide works.

Proper monitoring and timing of insecticides is essential for managing codling moth. If insecticides are applied too late, larvae will have tunneled into the fruit where they can no longer be controlled by insecticides.

Advanced

This pest affects:

Scientific Name
Cydia pomonella

Identification
Eggs:

Laid individually
Flat, elliptical
Almost transparent
1-2 mm in diameter
Rarely seen on fruit

Larvae:

5 larval instars
2-3 mm long, pale creamy white with a black head capsule when newly emerged
12-20 mm in length, cream or pink with a brown or black head at maturity

Pupae:

Brown
10-12 mm long
Found within silken cocoon on trunks or large branches

Adults:

9-12 mm long
Wingspan of 19 mm
Greyish brown with alternating bands of grey and white
Tips of the forewings are bronzed
Mainly active at dusk

Damage:

Small “stings” on the fruit surface
Interior breakdown of tissue caused by tunneling into fruit
Entry/exit holes can occur on the side or bottom of the fruit and is often plugged with brown, sawdust like, frass
Fruit with extensive tunneling often abort prematurely
Fruit with surface feeding may remain on the tree until harvest

Often Confused With

Plum curculio - larvae are legless, white, grub-like (slightly curved, C-shaped) and no clearly defined entry hole or frass present

Biology
Codling moth overwinters as mature larvae in silken cocoons under loose bark on the tree trunk and limbs. Cocoons are also found in leaf litter under the tree, piles of wood, brush, posts and occasionally mulch. Recent research shows larvae can also overwinter in storage bins and on the walls of packing sheds and other buildings adjacent to the orchard. In mid- to late April, larvae pupate inside the cocoon. The first adult usually emerges around bloom, while peak emergence occurs within four to five days after the first moth has emerged. Adult emergence is highly dependent on weather conditions. Cool temperatures delay emergence by 10-12 days. High temperatures cause early emergence in the spring and result in the deposition of more eggs. Late emerging adults from the overwintering pupae may not appear in orchards until six or seven weeks after petal fall.

After mating, female moths can lay up to 100 eggs. Eggs are laid individually primarily on the leaves. Eggs hatch in 6-14 days depending on temperatures. Larvae then search out the fruit where they anchor themselves and begin to feed. First instar lavae enter fruit predominantly through the calyx or just beneath the calyx lobes. After entering the fruit, they feed inside the pear for approximately three weeks before emerging to seek a site to pupate (tree trunk or larger branch of the tree). Pupation generally lasts 14-21 days. Some larvae do not pupate at this time, but remain as larvae until the next year. Second generation adults begin to appear in orchards as early as July and lay eggs over two months. Mature larvae of the second generation start leaving the fruit in mid August and continue until harvest or when temperatures drop. In some areas, unusually high daily temperatures during the summer can result in a partial third generation of codling moth. This third generation can result in larvae-infested fruit at harvest if control measures are not taken. It is often called a suicide generation because larvae are unable to complete their development due to the onset of winter.

Pears are less susceptible than apples to codling moth until they start to ripen.

Period of Activity
Injury to pears caused by codling moth occurs during second or partial third generation as fruit start to soften during ripening.

Management Notes
Remove fruit left on trees after harvest to reduce the population of overwintering larvae.

Remove props, picking bins, and fruit piles from the orchard.

Proper pruning and orchard sprayer calibration will improve spray coverage.

An option for small, organic orchards is hand thinning to remove all infested fruit during each generation, before worms leave fruit, and removal of dropped fruit.

The cultivar `Anjou' is the least susceptible to codling moth damage, followed by `Comice', `Bosc', and finally `Bartlett'. Differences in host susceptibility are due to the formation of stone cells below the epidermal layer, which impede the movement of young larvae into the fruit.

Some areas of the United States use mating disruption in conjunction with insecticides to manage codling moth. Growers in the northeastern United States and Canada are not advised to use mating disruption alone to manage codling moth because it is less effective in controlling codling moth than other pests (oriental fruit moth). For more information on using mating disruption for codling moth refer to Pub 360 Guide to Fruit Production or OMAFRA factsheet Mating Disruption for Management of Insect Pests. In orchards with a history of codling moth pressure, mating disruption ties should be applied at White Bud.

Codling moth is considered a minor pest of pear in Ontario, usually found in the borders of blocks near wild apple trees.

Management with insecticides – Insecticides are used to control codling moth in commercial pear orchards with a history of injury, especially those near infested apple orchards . See OMAFRA Publication 360, Fruit Crop Protection Guide.

Chapter 5 - Pear Calendar only: Recommendations for codling moth when monitoring indicates the need at Special Spray Trace bloom, and Special Spray (mid-August to early September).

Some information included above excerpted from;

Tender Fruit

Codling Moth

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