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Pest Alert: Found One Codling Moth in the Canyon County Apple Trees
Apple Treasure Valley, Treasure Valley - Idaho, Eastern Idaho, Magic Valley
Apple Codling Moth
Posted on: May 28, 2025 by Jemila Chellappa
Codling moth is a key insect pest of apples and pears in Idaho. Left unmanaged, it can cause "wormy" fruit and significant crop loss.
Identification – Know the Signs & Symptoms
Stage | Identification |
Adult Moth | Grayish-brown, 1/2 inch long, with a coppery-brown band at wing tips. |
Egg | Tiny, flat, and translucent – laid singly on fruit or leaves. |
Larva | Creamy white to pink caterpillar with a dark brown head – this is the “worm.” |
Pupa | Formed in bark crevices or leaf litter in silken cocoons. |
Symptoms on Fruit:
- Small, dark entry holes ("sting") on the apple surface.
- Frass (sawdust-like excrement) near the hole.
- Tunnels inside the fruit leading to the core.
- Premature fruit drop in severe infestations.
Current Monitoring & Degree Days
- Biofix (first moth detected): Mid-May
- Current Degree Days (base 50°F): 206 DD as of May 18
- Egg hatch begins: 220–250 DD – NOW is the time for action!
Management Options
Option A: Early Prevention (Egg Smothering)
- When: At 200 DD
- Action: Apply horticultural oil (1% concentration) to suffocate eggs.
- Follow-Up: Insecticide at 350 DD.
Option B: Target Larvae
- When: 220–250 DD
- Action: Apply insecticides to kill newly hatched larvae before they burrow into fruit.
Insecticide Options: Refer https://pnwhandbooks.org/insect/tree-fruit/apple/apple-codling-moth
Always read and follow the label directions for safety and effectiveness.
Non-Chemical Options
- Fruit Bagging: Bag individual fruitlets to block larvae entry.
- Sanitation: Remove dropped fruit and prune trees to reduce overwintering sites.
- Trapping: Use pheromone traps to monitor moth flights and guide sprays.
Season-Long Strategy: Codling moth has multiple generations per season. Continue monitoring traps and tracking degree days to time follow-up sprays or control measures.
Helpful Resources
https://climate.usu.edu/includes/pestFactSheets/Codling-Moth.pdf
https://extension.colostate.edu/topic-areas/insects/codling-moth-control-in-home-plantings-5-613/
For more assistance, contact your local University of Idaho Extension office https://www.uidaho.edu/extension/directory/counties
Keep your fruit clean and healthy – act now!
Pest Alert - Eastern Idaho
All Crops Eastern Idaho
Pest Alert Newsletter - Eastern Idaho
Posted on: May 12, 2025 by Jemila Chellappa
Pest Alerts from Bonneville County – Eastern Idaho
As temperatures begin to rise across, many of us are starting to notice increased insect activity in our fields, gardens, and landscapes.
It’s natural to feel the urge to reach for an insecticide at the first sign of bugs—but we encourage you to pause and take a closer look. Not all insects are harmful, and many play important roles in pollination, natural pest control, and maintaining ecological balance.
Spraying too early or without proper identification can unintentionally harm beneficial insects and disrupt the natural balance of your growing environment. Whenever possible:
Identify the insect first—Is it a pest, a predator, or a pollinator?
Monitor populations—Are the numbers high enough to justify treatment?
Consider non-chemical options, such as biological or cultural controls.
Let’s work together to protect both our crops and our ecosystem. Reach out to your local Extension office for help with insect ID and integrated pest management (IPM) strategies tailored for your area. https://www.uidaho.edu/extension/directory/counties
Stay informed, and spray smarter! Find more information in the attached newsletter
