Small Farms & Acreage Alerts
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Early Pest Detections - Codling Moth & Peach Twig Borer
Apple Treasure Valley, Treasure Valley - Idaho, Treasure Valley Oregon
Codling Moth & Peach Twig Borer
Posted on: March 24, 2026 by Jemila Chellappa
Pest Alert: Early Detection of Codling Moth & Peach Twig Borer
Location: Farmway & Karcher area, Treasure Valley, Idaho
Date: March 24, 2026
Backyard growers in the Farmway and Karcher area have reported early captures of key orchard pests in delta traps:
- Codling moth (Cydia pomonella) – 1 adult captured
- Peach twig borer (Anarsia lineatella) – 1 adult captured
These detections are earlier than typically expected, signaling that pest activity has begun in localized areas.
What This Means
- This may represent early flight initiation (biofix approaching or beginning) for both pests.
- Even low trap counts are important—they indicate the start of adult emergence.
- Warmer early-season conditions may be accelerating development.
Recommended Actions for Growers
- Deploy traps immediately if not already in place (especially in apples, pears, peaches, nectarines).
- Check traps regularly (2–3 times per week) to monitor trends.
- Record first consistent captures to establish a reliable biofix.
- Begin tracking Growing Degree Days (GDD) for precise timing of:
- Egg hatch (Codling moth)
- Larval emergence (Peach twig borer)Why It Matters
Why It Matters
Accurate timing based on trap data + GDD allows for:
- Improved spray timing
- Reduced unnecessary pesticide applications
- Better pest control and fruit protection
Stay Connected
Continue monitoring updates through the PNW Pest Alert Network for region-specific guidance and GDD-based recommendations.
Onion Growers Alert
All Crops Treasure Valley, Treasure Valley - Idaho, Eastern Idaho, Magic Valley, Northern Idaho, Treasure Valley Oregon
Cull Onion Disposal
Posted on: March 4, 2026 by Jemila Chellappa
Growers are reminded that the deadline to dispose of existing cull onion piles is March 15 to help prevent the buildup of onion pests such as onion maggot.
Key Requirements
All existing cull onion piles must be disposed of by March 15.
From March 15 to July 1, any new cull piles must be disposed of within one week of creation.
Proper disposal is essential to reduce pest development and protect nearby onion fields.
Management Options
If cull onions cannot be buried in a timely manner, piles may be treated with an approved insecticide labeled for cull piles or non-crop areas.
Approved options previously identified include:
Malathion products
Gowan Malathion 8 Flowable – EPA Reg. No. 10163-21
Malathion 5 EC – EPA Reg. No. 66330-220
(Malathion is generally the most economical option.)
Azadirachtin products
AzaGuard – EPA Reg. No. 70299-17
Ecozin Plus 1.2% ME – EPA Reg. No. 5481-559
Gowan Aza-Direct – EPA Reg. No. 71908-1-10163
Always read and follow pesticide label instructions before application.
Additional Regulations
In Malheur County, Oregon, no more than 80 tons of onion debris may be buried per acre.
State regulations related to onion maggot management and cull disposal can be found in the links below.
Additional Resources
Oregon rule: https://secure.sos.state.or.us/oard/viewSingleRule.action
Idaho rule (onion maggot section begins on page 8): https://adminrules.idaho.gov/rules/current/02/020605.pdf
