CORVALLIS, Ore. — The codling moth is often the most damaging insect in home orchards of apples, pears, plums and walnuts. Many gardeners default to repeated insecticide sprays, but several less-toxic methods can significantly reduce damage.
Adults begin to emerge as apples bloom. Moths are small (about 3/4-inch wingspan) and gray-brown with bronze near the wing tips. The caterpillar — “the worm in the apple” — is about 1/2 inch long, white with a pink hue and a brown head.
Newly hatched larvae bore into fruit, feed for about three weeks, then pupate on the tree or ground. Depending on location and season length, two to three generations can occur each summer.
Regional considerations for Oregon
Western Oregon (Willamette Valley/Coast)
- First flight commonly begins late April to May.
Southern Oregon (Rogue/Umpqua valleys)
- Often earlier than the Valley; warm springs can advance first flight to mid-April.
Central Oregon (High Desert)
- Cooler nights delay activity; expect first sustained trap catch late May into June, with second generation peaking mid- to late July. Use row covers for late frosts on trees and hang traps early so you don’t miss the start.
Eastern Oregon (Columbia Plateau/Basin/Blue Mountains)
- First flight typically May, with strong second generation in July during hot spells.
Pheromone lures and traps
Delta or wing traps baited with synthetic pheromone lures and a sticky insert attract and catch males. Hang traps at bloom and check weekly to track first and peak flights. In small backyards, trapping removes many males and — most importantly — tells you when fruit needs protection so you can avoid unnecessary sprays.
Sanitation and banding
Sanitation is one of the most important steps.
- Scout and remove infested fruit during the season; don’t let dropped fruit sit — larvae can keep feeding inside it.
- Cardboard trunk bands: Wrap corrugated cardboard around trunks to attract wandering larvae looking to pupate. Remove and destroy bands (and larvae) a couple of times per season. Keep the ground under trees clear of weeds and thick leaf litter to reduce alternate pupation sites.
Bagging individual fruit
Time-consuming but effective for backyard trees: slip a mesh bag over each fruit soon after petals fall and secure it. The physical barrier prevents egg-laying and larval entry.
Using insecticides — if monitoring indicates pressure
If trap counts show sustained moth activity, you may choose an over-the-counter insecticide labeled for home orchards and for your crop. Time sprays to the start of egg hatch (shortly after first consistent male trap catch) and follow label intervals.
Options sold to homeowners often include products with spinosad, codling moth granulosis virus, kaolin clay particle film, or other labeled actives. Rotate modes of action as directed, observe preharvest intervals, and protect pollinators — do not spray during bloom and apply in the evening when bees are not active.
When to consider sprays
Well-timed, need-based applications (guided by traps) reduce total spraying and improve results compared to calendar-only programs. For specific timing and product guidance, see resources below.
Resources
Previously titled How to safely control codling moths in home orchards
¡Use los pesticidas con seguridad!
- Póngase ropa de protección y equipo de seguridad según las recomendaciones de la etiqueta. Báñese después de cada uso.
- Lea la etiqueta del pesticida—aunque lo haya usado antes. Siga al pie de la letra las indicaciones de la etiqueta (y cualquiera otra indicación que Ud. tenga).
- Tenga precaución al aplicar los pesticidas. Conozca su responsabilidad legal como aplicador de pesticidas. Usted puede ser responsable de heridas o daños resultantes del uso de un pesticida.
