Lure Replacement & So Traps Never Lie

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.

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.

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.

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.

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.

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.

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.

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.

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.