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How to identify it
- Adult size figures differ: UC IPM gives about 1/2 to 3/4 inch, Utah State and Colorado State about 1/2 inch, and Minnesota about 3/8 inch. The mottled gray wings, with narrow alternating gray and white bands, are held tentlike over the body and blend in with bark.[1][2][5][6]
- A dark, coppery brown band or spot at the tip of each forewing sets codling moth apart from other moths caught in traps.[1][2][5][6]
- Full-grown larvae are about 1/2 to 3/4 inch long, creamy white to pinkish with a brown or black head; Minnesota gives up to 1/2 inch.[1][2][5][7][6]
- Sources use the word sting differently. UC IPM calls the larval entry hole, marked by a tiny mound of reddish-brown frass about 1/16 inch across, a sting, and Colorado State describes a light red ring around it. Utah State keeps the word for healed shallow or abandoned entries and calls the rest deep entries.[1][5][2]
- Larvae often enter where fruit is sheltered, such as the stem or calyx end or where two fruits touch; in pears, entry is mostly at the calyx end.[5][7]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Navel orangeworm (in walnuts) | Navel orangeworm larvae have crescent-shaped markings on the second segment behind the head and leave much more webbing in the nut.[1] |
| Plum curculio larva | Plum curculio grubs inside fruit are legless, C-shaped and grayish white with a small brown head, about 1/3 inch long, while codling moth larvae are white to pinkish caterpillars with a dark brown head.[3][1] |
Where it lives
Codling moth is the most serious pest of apple and pear worldwide and a major pest of home fruit trees in states such as California and Utah.[2][1]
Biology and life cycle
Full-grown larvae spend the winter in silken cocoons under loose bark or in soil and debris at the base of the tree, then pupate in late winter or early spring.[1][2][5][7]
Moths are active a few hours before and after sunset. Temperature thresholds differ: UC IPM says they mate when sunset temperatures exceed 62°F, Colorado State that egg laying increases as night temperatures rise above 62°F, and Utah State that moths become active once evening temperatures exceed 55 to 60°F.[1][5][2]
Each female lays 30 to 70 tiny, flat, disc-shaped eggs singly on fruit, nuts, leaves or spurs; Minnesota says up to 100. Eggs hatch in 6 to 14 days, depending on temperature.[1][2][5][6]
Newly hatched larvae bore into fruit within a day, tunnel to the core to feed on the seeds, then leave to find a pupation site.[2][5][1][6]
Generation counts vary with climate: two to four a year in UC IPM's account, two plus a partial third in northern Utah and a full third in southern Utah, and two in Minnesota and Washington.[1][2][6][7]
Minnesota says adults can fly as far as a mile to find apple trees, which is why neighbors' trees matter.[6]
Codling moth has become resistant to several groups of insecticides, which makes it harder to control.[8][9]
Damage and signs
- Larvae tunnel to the core of apples and pears, leaving holes filled with reddish-brown, crumbly frass, and uncontrolled trees can lose 20 to 90 percent of the fruit.[1]
- Fruit attacked early in spring often drops, and larvae can finish developing in the fallen fruit.[2][5]
- Early-maturing varieties are less likely to be damaged. Colorado State adds that firmer fruit is somewhat less susceptible and that late varieties stay on the tree long enough to be hit by a third generation.[1][5]
- In walnuts, larvae eat the kernels; early-damaged nuts drop, and later-damaged nuts stay on the tree with inedible kernels. Walnuts are a less favored host, and UC IPM says untreated trees may lose 10 to 15 percent of the nuts.[1]
- Larvae occasionally turn up in cherries, peaches and large-fruited crab apples, and infested crab apples can supply moths to nearby apple trees.[5]
Health risk
Codling moths don't bite or sting. If you eat wormy fruit, cut out damaged portions, because mold in them might produce toxins such as aflatoxin.[1]
Control
Prevention
Thin fruit so they don't touch, keep trees low enough to reach (WSU suggests under 10 feet), choose early-maturing varieties, and coordinate with neighbors, since moths fly in from nearby trees.[5][7][1]
Sanitation
Every week or two, starting six to eight weeks after bloom, remove fruit with frass-filled holes from the tree, and pick up dropped fruit promptly, especially in May and June. Destroy it rather than composting or leaving it, since larvae keep developing and then leave to pupate; WSU suggests sealing it in a plastic bag in the sun for a week.[1][5][7][6]
Remove loose bark flaps and debris where larvae spin cocoons, and check apple crates and storage buildings, which can shelter larvae through winter.[5][7][6]
Traps and physical control
Wrap trunks or branches with strips of corrugated cardboard or burlap so larvae leaving the fruit cocoon there, then check the bands every week or two and destroy the larvae.[5][7]
Bag young fruit about 4 to 6 weeks after bloom, when it is 1/2 to 1 inch across (WSU says 4 to 6 weeks after petal fall, about dime-size). Paper lunch bags work; WSU warns clear plastic bags hold moisture. UC IPM calls bagging the only nonchemical method effective enough to use alone.[1][5][7]
Biological control
Codling moth granulosis virus affects only codling moth larvae and won't harm beneficial insects or bees, but it needs repeated applications during egg hatch. Parasitic wasps and general predators help on trees sprayed only with selective products.[1][5]
Pesticides
Sprays work only if they reach larvae as they hatch, before they enter fruit. UC IPM times them with a pheromone trap and degree-days or by the first stings; Minnesota and WSU tie the first spray to petal fall, about 10 days after all petals drop in WSU's guidance. Don't spray during bloom.[1][2][6][7][5]
Spinosad is a lower-toxicity option. Carbaryl works but is very disruptive to natural enemies and bees, should never be applied during bloom, and is restricted use in California.[1][5]
Bt, pyrethrum and pyrethrin-rotenone mixes haven't proven effective. Mating disruption fails on small plantings: UC IPM says under 5 acres, Utah State and Colorado State under 10 acres.[1][2][5]
Common questions
- What are the small brown spots with holes on my apples?
- Probably codling moth entries: tiny mounds of reddish-brown frass, sometimes ringed with red, over the hole where a newly hatched larva went in.[1][5]
- Do codling moth traps protect my tree?
- Not reliably. Pheromone traps catch males and are mainly for timing sprays. UC IPM and Colorado State say several traps on an isolated tree might help a little, especially with lures that also draw females.[1][5]
- Can I control codling moth without spraying?
- On small trees, often yes. Bagging fruit plus diligent removal of infested and fallen fruit can work; trunk bands and thinning help, and UC IPM calls bagging the only nonchemical method strong enough to use alone.[1][5][7]
Sources
- University of California Statewide IPM Program, “Codling Moth (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/codling-moth/ (accessed 2026-11-11)
- Utah State University Extension and Utah Plant Pest Diagnostic Laboratory, “Codling Moth, Cydia pomonella (Fact Sheet ENT-13-06).” extension.usu.edu/files-ou/publications/factsheet/codling-moths06.pdf (accessed 2026-11-11)
- University of New Hampshire Extension, “Plum Curculio [fact sheet].” extension.unh.edu/resource/plum-curculio-fact-sheet (accessed 2026-11-11)
- iNaturalist, “Cydia pomonella taxon page (order and family).” www.inaturalist.org/taxa/47153 (accessed 2026-11-11)
- Colorado State University Extension, “Codling Moth: Control in Home Plantings, Fact Sheet 5.613.” extension.colostate.edu/topic-areas/insects/codling-moth-control-in-home-plantings-5-613/ (accessed 2026-11-11)
- University of Minnesota Extension, “Codling moths in home orchards (Jeffrey Hahn, reviewed 2019).” extension.umn.edu/yard-and-garden-insects/codling-moths (accessed 2026-11-11)
- Washington State University Extension, “Apple: Codling moth (Hortsense).” hortsense.cahnrs.wsu.edu/fact-sheet/apple-codling-moth/ (accessed 2026-11-11)
- Insects, via PubMed, “Kadoić Balaško M, Bažok R, Mikac KM, Lemic D, Pajač Živković I (2020), Pest management challenges and control practices in codling moth: a review, Insects 11(1):38.” pubmed.ncbi.nlm.nih.gov/31947812/ (accessed 2026-11-11). Cited from the PubMed abstract.
- Annual Review of Entomology, via PubMed, “Witzgall P, Stelinski L, Gut L, Thomson D (2008), Codling moth management and chemical ecology, Annual Review of Entomology 53:503-522.” pubmed.ncbi.nlm.nih.gov/17877451/ (accessed 2026-11-11). Cited from the PubMed abstract.