Lure Replacement & So Traps Never Lie
Tracks moths
Enter the start date, lure life and season length to get every lure-change dateacross the pest season — so traps keep catching and you never miss the spray window.
Plan lure replacements
Next: diarise the 4 replacement dates and fit a fresh lure each time — pair the swap with a sticky-base or floor change so the trap counts stay comparable week to week.
Lure life varies by pest, lure formulation, brand and field temperature — high heat ages lures faster. Treat the schedule as a planning baseline and replace early in hot spells.
Lure replacement — key facts
- Replacements
- season ÷ lure life
- Each date
- start + n × lure life
- Typical lure life
- ≈ 2–6 weeks
- Rubber septa
- ≈ 4 weeks
- Heat & sun
- shorten lure life
- Old lure
- trap under-counts pests
- Goal
- keep the spray window honest
- Privacy
- Runs in your browser; nothing uploaded
A fresh lure is the difference between catching and guessing
Pheromone traps are only as good as the lure inside them. The pheromone evaporates day after day, and once the release rate drops the trap stops pulling in moths — the catch falls even as the real population climbs. Acting on a stale lure means you read low numbers, hold off on spraying, and discover the pest only after eggs are laid and the damage window has slipped past. The cure is simple: replace lures on a schedule through the whole season.
This tool lays that schedule out from your inputs — it gives the number of replacements, each replacement date, the last date and the lure life across the season. Use it to plan field visits, batch lure orders and keep every trap honest so threshold crossings are real. Pair it with the Pheromone Trap and Light Trap calculators for a complete monitoring plan.
Traps stay honest
Fresh lures keep the catch a real signal.
Hit the spray window
Act when moths fly, not after damage.
Plan field visits
Every change date set for the season.
Order lures right
Know how many lures the season needs.
Frequently Asked Questions
Why do pheromone lures need replacing?+
The pheromone in a lure evaporates steadily, so its release rate falls over time. Once it weakens, the trap attracts fewer moths and the catch under-counts the real population — you think pressure is low when it is rising. Replacing lures on schedule keeps the release rate high enough that catches stay a reliable signal for timing sprays.
How are the replacement dates calculated?+
From the start date, each new lure goes in one lure-life later, repeated until the season ends. So with a 4-week lure life over a 16-week season you replace at weeks 4, 8 and 12 — giving the number of replacements, each replacement date, the last date and the lure life used. The tool lays the whole calendar out at once.
How long does a pheromone lure last?+
It depends on the lure type and the weather, but most field lures last about 2–6 weeks, with rubber septa often around 4 weeks and longer-life dispensers up to several weeks more. Heat and strong sun shorten that life. Use the maker's stated longevity as the lure-life input, then shorten it in hot conditions.
What happens if I leave a lure too long?+
An old lure releases too little pheromone, so the trap catches fewer moths than are actually flying. That makes the population look low and you delay spraying — then the pest has already laid eggs and the damage window has passed. Stale lures cause missed spray timing far more often than they cause false alarms.
Does weather change lure life?+
Yes. High temperatures and direct sun speed evaporation, so lures fade faster in peak summer and last longer in cool, shaded conditions. If your season is hot, set a shorter lure life so replacements come more often. The calculator simply uses whatever lure life you enter, so adjust it to your climate.
How do I match this to the spray window?+
Lures keep the trap catch honest; the catch then tells you when moth flight peaks and a spray is due. By replacing lures on schedule you ensure the catch is reliable through the whole flight period, so the threshold crossings you act on are real. Pair this with a Pheromone Trap calculator to size trap numbers first.
Can I use it for any pest or crop?+
Yes — it works for any pheromone-trapped pest, since you supply the lure life and season length yourself. Whether you monitor fruit borers, stem borers, fruit flies or moths in vegetables, orchards or field crops, the replacement schedule is just start date plus repeated lure-life intervals across the season.
Should I replace all traps' lures together?+
Replacing all lures on the same dates keeps the network consistent, so catches across traps stay comparable and the schedule is easy to follow. Batch the changes on each replacement date, dispose of old lures away from the field, and avoid handling new lures with bare hands so skin oils and food smells do not contaminate them.
Are the dates exact?+
They are solid planning dates from the lure life and season you enter. Real longevity varies with the product, temperature, humidity and sun exposure, so check trap catches — if numbers drop oddly, replace early. Treat the calendar as a maintenance reminder and trust your field observations over the calendar when they disagree.