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Ministry of Agriculture, Food and Rural Affairs

Codling Moth (CM)

Codling moth larvae (Alex Molnar, Agriculture and Agri-Food Canada, London) Codling moth adult Sting (Dr. Ian Scott, Agriculture and Agri-Food Canada, London) Seed feeding Fruit damage on side of fruit Fruit damage on calyx Codling moth sting Codling moth seed feeding
Click to enlarge.

Beginner

Scientific Name
Cydia pomonella

Identification
Eggs:

  • Flattened,
  • Elliptical,
  • Almost transparent,
  • 1-2 mm in diameter and are rarely seen on fruit.

Larvae:

  • 2-3 mm in length and pale creamy white with a black head capsule when newly emerge,
  • 12-20 mm in length, cream or pink with a brown or black head at maturity,

Pupae:

  • Brown,
  • Vary in size from 10-12 mm in length.

Adults:

  • 9-12 mm in length
  • Wingspan of 19 mm,
  • Grey brown in colour 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 tunnelling into fruit, the exit hole can occurs on the side or bottom of the fruit and is often plugged with frass,
  • Fruit with extensive tunnelling often aborts prior to harvest, fruit with surface feeding may remain on the tree until harvest,

Often Confused With

Period of Activity
Bloom through to mid June. 2nd generation moths emerge in early August. Mature larvae of the 2nd generation leave fruit as early as late August and well into October.

Scouting Notes
Place pheromone traps in orchard at bloom to monitor codling moth adults. Collect and input information on maximum and minimum daily temperatures into a degree day model.

Thresholds
Threshold for 1st generation codling moth is based on a degree day model. Apply insecticides targeting larvae at 125 DDC (base 10°C) after first sustained moth catch, and apply insecticides targeting eggs at 50 DDC (base 10°C). 

Advanced

Scientific Name
Cydia pomonella

Identification
Codling moth eggs are 1-2 mm in diameter, flattened, elliptical and almost transparent. Their small size means they are rarely seen on fruit. Newly emerged larvae are about 2-3 mm in length and pale creamy white with a black head capsule. Mature larvae are approximately 12-20 mm in length and are cream or pink with a brown or black head. There are five larval instars. Pupae are brown and vary in size from 10-12 mm in length. The adult is approximately 9-12 mm in length with a wingspan of 19 mm. It is grey brown in colour with alternating bands of grey and white. Tips of the forewings are bronzed. Adults are mainly active at dusk. In Ontario there are two generations of codling moth per year, except in the coolest areas (Georgian Bay) where there is only one generation.

Larvae damage the fruit by feeding minimally on the outside of fruit creating small “stings” on the fruit surface and tunnelling into fruit, and feeding on the pulp and seeds causing extensive interior breakdown of tissue. Fruit with extensive tunnelling often aborts prior to harvest, while fruit with surface feeding may remain on the tree until harvest. This injury causes internal breakdown of the fruit often leading to premature drop. The exit hole – where mature larva emerged – is often plugged with frass. Exit holes can occur on the side or bottom of fruit. If uncontrolled, codling moth can damage 50% to 90% of the crop.

Often Confused With

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 over-winter 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 first generation adults 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 on the fruit or leaves. Eggs hatch in 6-14 days depending on temperatures. Larvae then search out the fruit where they anchor themselves and begin to dig into the fruit. After entering fruit they feed inside the apple for approximately three weeks, leaving the fruit 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. Moths lay eggs over two months and mature larvae of the second generation start leaving the apples in mid August and continue until apples are removed from the orchard or temperatures drop. In some areas (Michigan) unusually high daily temperatures during the summer can result in a partial third generation of codling moth. This third generation can result in worm-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.

Period of Activity
1st generation adults emerge from bloom through to mid June. First generation larvae are present in fruit from mid June to late August. 2nd generation moths emerge in early August and flight can continue until late September. 

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 first generation adults may not appear in orchards until six or seven weeks after petal fall.

Second generation adults begin to appear in orchards as early as July. Moths lay eggs over two months and mature larvae of the second generation start leaving the apples in mid August and continue until apples are removed from the orchard or temperatures drop.

In some areas (Michigan) unusually high daily temperatures during the summer result in a partial third generation of codling moth in some years. This third generation can result in worm-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.

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 for each generation 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. Use traps to determine first sustained moth catch, this information is used in conjunction with a degree-day model, to predict when the eggs are hatching and when to apply insecticides targeting larvae. 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.

Thresholds
Threshold for 1st generation codling moth is based on a degree-day model. Apply insecticides targeting larvae at 125 DDC (base 10°C) after first sustained moth catch, and apply insecticides targeting eggs at 50 DDC (base 10°C). 

Apply 2nd generation codling moth insecticides targeting larvae at 600 to 625 DDC (base 10˚ C).

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. The developmental model to predict timing of codling moth sprays is:

DDC =  maximum °C + minimum °C    - 10°C
                                             2

The accumulation of these degree-days is initiated by the biofix – first sustained moth catch of the 1st generation. 

Management Notes

  • The application of insecticides to manage codling can vary depending on the lifestage targeted. For insecticides targeting larvae, OMAFRA recommends spraying at 125 DDC (base 10°C) after biofix. Apply ovicides at 50 DDC (base 10°C) after biofix. For second-generation codling moth, apply larvicides at 600 to 625 DDC (base 10°C) after biofix from the first generation flight. See OMAFRA Publication 360, Guide to Fruit Production - Chapter 3 Apples (PDF) or Apple Calendar only (PDF) :
  • To determine the best timing of a particular insecticide to control codling moth, and to find products that also control other pests simultaneously (apple maggot) see OMAFRA Publication 310, Guide to Fruit Production.
  • Research shows codling moth populations in Washington, Oregon, Michigan and elsewhere has developed resistance to OP insecticides (Guthion, Imidan, Zolone). Preliminary research conducted by Agriculture and Agri-Food Canada suggests OP resistance is present in some apple orchards in Ontario. To deter the development of pesticide resistance, follow an insecticide resistance management strategy. Refer to OMAFRA Publication 360, Guide to Fruit Production, as well as 310, Integrated Pest Management for apples.
  • 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 (Order No. 03-079).
  • Border spray programs can be a very effective way to manage codling moth. In a border spray program, apply an initial cover spray of OP insecticides to eradicate any codling moths residing in the orchards.  Subsequent border sprays of OP are used in a four-tree wide (20 m) zone around the perimeter of the orchard to control codling moths migrating into the orchard after the initial cover spray.
  • Border sprays can not be used with all products, refer to pub 360 Fruit Production recommendations and OMAFRA Publication 310, Integrated Pest Management for Apples, for more information on using border sprays.
  • There are few effective cultural or biological controls to help manage codling moth. Predators, such as ground beetles (Carabidae), ants and crickets, and parasitic wasps, attack larvae as they leave fruit and crawl towards tree trunks, but do not provide economically acceptable levels of control.