For growers, pest control advisors, and consultants evaluating sterile insect release.
GROWER’S
GUIDE
A grower’s guide to codling moth control with sterile insect release.
Biology, implementation, monitoring, and program economics in one place.
How sterile insect release works
Sterile moths are released in overwhelming numbers. When wild females mate with sterile males, they produce eggs that do not develop, and the population declines across generations without selecting for resistance.
- 01
Quality control
Sterile moths are tested for flight performance, emergence rates, and mating competitiveness before release. Only moths that meet quality thresholds reach grower orchards.
- 02
SIR and mating disruption
These are complementary tools that work through distinct pathways. Research in New Zealand found that combined SIT and mating disruption programs reduced wild moth captures by 67 to 99 percent over six years.
- 03
The measure that matters
The most reliable indicator of success is harvest damage assessment, the percentage of fruit with codling moth entries.
Is SIR right for your operation?
SIR is a population suppression tool. It works best when the population it starts with is manageable. SIR is not intended to function as a stand-alone tool.
| Question | SIR-favorable answer |
|---|---|
| Codling moth damage last season? | Low to moderate |
| Organic operation or organic goals? | Yes |
| Can you commit to a 3-year minimum? | Yes |
| Can you maintain year-one spray support? | Yes |
| Do you have harvest damage data? | Yes |
Five favorable answers make a strong candidate. Three or four warrant a detailed assessment. Fewer than three suggests addressing other priorities first.
SIR works best with a 3-season commitment, spray support kept through the first 1 to 2 seasons, and blocks of 50 acres or more or neighbors who participate.
What to expect, year by year
Timing depends on monitoring data, not the calendar.
- 01
Year 0, pre-program
Establish a baseline: harvest damage assessment, trap count records, and the sources of pressure. Map the blocks and design the year-one spray support plan.
- 02
Year 1, the intensive year
Maintain the spray program, possibly at full intensity, while releases begin to suppress the wild population. Keep the damage records and note how trap counts relate to edge blocks and historically high-pressure zones.
- 03
Years 2 to 3
The years in which the program shows in the records. Growers begin reducing spray passes on later generations when their monitoring supports it.
- 04
Year 4 and beyond
Transition to the maintenance rate. Some low-pressure blocks reach maintenance by year three; higher-pressure blocks take longer.
- 05
High pressure, 5 or more years
A block starting from heavy damage or beside large unmanaged acreage needs a combined approach: intensive trapping, full spray support on every generation, high-volume application, sanitation, and possibly barrier netting. SIR is one component of that recovery plan.
What M3 handles and what you handle
M3 runs the cold chain, flies the aerial releases over the 20-week program, designs the program to your pressure profile, and supports monitoring interpretation.
| Your responsibility | Why it matters |
|---|---|
| Pheromone trap monitoring | The primary population data for adjusting the program |
| Trap maintenance | Stale lures undercount moths, and inaccurate counts lead to wrong decisions |
| Harvest damage assessment | The primary success metric, sampled systematically |
| Spray program coordination | Release timing must coordinate with sprays; some insecticides are toxic to sterile moths |
| Record keeping | Trap counts, damage data, and spray records enable year-over-year improvement |
| Access for release flights | Release crews need clear access and advance coordination |
The standard program begins in late April and delivers 800 moths per acre per week for 20 weeks, timed by degree-day accumulation and codling moth phenology.
Monitoring protocol
- 01
Trap placement
One trap per 5 to 10 acres as standard, one per acre in problem blocks, at mid-canopy height with the opening facing the prevailing wind.
- 02
Trap maintenance
Replace lures every 2 to 3 weeks. Replace sticky inserts when 30 percent or more of the surface is covered.
- 03
Sterile or wild
Sterile moths are dye-marked. A high marked-to-unmarked ratio indicates effective overflooding at the trap, though damage assessment remains the authoritative measure.
- 04
Harvest damage assessment
Sample at least 25 fruit per tree from 10 trees per block location, interior and edge separately. Record fruit with codling moth entries, stings and deep damage, and track year over year.
- 05
Reading traps under mating disruption
Mating disruption reduces trap catch independent of population density, so the marked-to-unmarked ratio is the more reliable indicator. Cross-reference low catches with damage assessment before drawing conclusions.
- 06
When to call M3
Unmarked catches well above expected levels after ruling out lure and trap issues; damage increasing after year two; damage patterns inconsistent with prior years; a spray reduction you want a second opinion on.
The economics
2027 rates for Washington and Oregon. A 20-week release season with a 5-acre minimum. Larger operations receive lower per-acre rates.
| Coverage | Moths per acre per week | Under 100 acres | 100 to 1,000 acres | 1,000+ acres | Best fit |
|---|---|---|---|---|---|
| Half rate | 400 | $345 | $335 | $325 | Low pressure, maintenance, expanding coverage |
| Full rate | 800 | $455 | $440 | $425 | Low to medium pressure, IPM supplement |
| Double rate | 1,600 | $675 | $655 | $640 | Medium to high pressure, hotspots, recovery |
| Triple rate | 2,400 | $895 | $865 | $835 | Three times the full rate |
| Full rate, 24-week season | 800 | $546 | $528 | $510 | A longer season at the full rate |
| Full rate, twice a week | 1,600 | $775 | $755 | $735 | The full rate, released twice a week |
| Double rate, twice a week | 3,200 | $1,215 | $1,175 | $1,135 | The double rate, released twice a week |
Some organic growers already spend $1,000 to $2,000 per acre on codling moth sprays. SIR at $325 to $675 per acre, half to double rate, can help bring total costs down over time as spray passes decrease.
For organic growers the calculation includes the organic premium per bin, the value of fewer chemical alternatives as CpGV resistance erodes, and the cost of a season whose damage exceeds packing house tolerances.
“If you’re organic it will pay off within like three years. You can stay in organic. It’s just going to be hard for a couple years.”Teah Smith, Zirkle Fruit
“The mistake we’ve made in making suggestions is to focus on too small of an area. When we start looking at how to be most effective, we need to also look outside the hot spot and see how the population tapers off across the orchard.”Jeff Allen, GS Long Company
Talk to M3
Bring what you have. Partial information is fine; M3 can reconstruct a picture from limited data.
- Last season’s harvest damage data
- Prior-season trap count records
- A block map or acreage breakdown
- Current spray program details
- Specific problem areas