Clothes Moth Trap Troubleshooting Guide
Pheromone moth traps are highly effective tools, but several factors can affect how many moths they catch. In my 20 years as a pest controller and using pheromone traps I have found that the most common reasons for poor catches are incorrect moth identification, trap placement, using too many traps, nearby repellents, air movement and simply being at the wrong stage of the moth's breeding cycle. Before assuming that your traps aren't working, work through the checks below.
1. First, make sure you have the right species of moth. This is the most important check, moth pheromones are species-specific. A pheromone designed for clothes moths will not necessarily attract every small moth flying around your home, London Moth clothes moth traps are intended for the;
Common Clothes Moths/Webbing Clothes Moths (Tineola Bisselliella),
Case-bearing/making Clothes Moths (Tinea Pellionella),
Pale-backed Clothes Moths (Monopis Crocicapitella).
However, clothes moth traps are not designed for food/pantry moths or unrelated household moth species, including these common visitors and potential pests:
Indian Meal Moths (Plodia Interpunctella),
Brown House Moths (Hofmannophila Pseudospretella),
White -shouldered House Moths (Endrosis Sarcitrella).
This means that seeing moths flying around your property while your trap remains empty can actually indicate that the moth you are seeing is not the species targeted by the pheromone. Correct identification should therefore always be your first step.
CHECK THE GUIDE OUTLINING THE SPECIES OF MOTHS YOU MAY SEE IN THE HOME.
2. Remember that pheromone traps attract male moths. The pheromone lure mimics the chemical signal produced by female clothes moths and attracts adult males. The trap does not attract eggs or larvae, and it should not be expected to catch every adult moth in the room. This is particularly important because the larvae cause the damage to carpets, clothing and other natural fibres – not the adult moths, identifying where activity is greatest and observing changes over time.
3. DO NOT use too many traps in the same room and close by one another. It can be so tempting to think: "If 1 trap is good, then surely 5 traps must be 5 times better". That isn't necessarily the case and a very common mistake when using pheromone traps. Each trap releases pheromone into the surrounding air and the male moth uses this chemical signal to locate what it perceives to be a female. Placing multiple pheromone traps very close together can create several competing pheromone sources and oversaturate the local atmosphere. Rather than giving the moth one useful scent plume to follow towards a trap, the surrounding atmosphere contains abundant overlapping pheromone signals. This can make orientation towards an individual trap less likely and is totally confusing the odour detecting antennae of the targeted moth. For this reason, more traps does not automatically mean more moths caught. Follow the recommended trap density and space the traps significantly far enough apart rather than filling a single room with traps. With the volume of traps in a London Moth pack, it is usually more useful to distribute them logically through different areas of the property than to cluster them together. You should also NEVER place a fresh trap next to an existing one of whatever brand still within it's expiry and expect it to catch more moths than the older one. You may perceive that a freshly opened trap will have a stronger pheromone plume, but pheromones are very slow releasing and an older trap will ALWAYS catch more moths than a freshly laid one. This slow release ensures that traps can be extremely laong lasting.
4. Trap position matters. A pheromone trap can only work effectively if a male moth can locate the pheromone plume. Avoid simply putting the trap wherever it looks most convenient such as on top of a coffee table or your bedside table. Think like a moth and where moth activity is actually likely to originate (i.e dimly lit areas, out of the way of light and human activity).
Good areas to investigate include: carpet edges and skirting boards underneath and behind furniture, wardrobes and dressing areas, undisturbed rooms, cupboards containing natural-fibre clothing, underneath beds and under tables around wool carpets and rugs, upholstered furniture and other dark, quiet areas where textiles remain undisturbed. If you consistently catch more moths in one area than another, that information can help you narrow down the location of the infestation.
5. Avoid strong draughts and excessive air movement. The pheromone needs to disperse through the air in a way that allows a male moth to follow the scent towards its source. Positioning a trap immediately beside an open window, powerful fan, air-conditioning outlet or other strong air current may disperse the pheromone too rapidly or carry it away from the area you are trying to monitor. Likewise, don't hide the trap somewhere with virtually no useful air circulation. The aim is gentle natural air movement, allowing the pheromone plume to disperse through the area without being continually blown away. If a trap isn't performing as expected, consider its relationship with: windows – doors – extractor fans – air conditioning – heating vents – portable fans before moving it.
6. DO NOT place moth repellents next to pheromone traps or spray moth repellent near the traps. This is an easily overlooked problem. A pheromone trap is attempting to attract a male moth and a moth repellent is intended to discourage moth activity around an area. Using both immediately alongside one another is therefore extremely counterproductive. Products containing strongly scented materials such as cedar, lavender or other moth-repellent fragrances should not be positioned immediately beside your pheromone trap. If you are trying to monitor moth activity accurately, keep attractant traps away from areas where strong repellents are being used. Think of it simply: The trap is saying "oi mate come over here!" and the repellent is saying " oi mate, keep away!". Fundamentally, you should give the pheromone trap a reasonable area in which to operate without competing fragrances.
7. Understand intermittent moth breeding cycles. Another very common reason customers think their traps have stopped working is that moth populations do not remain constant throughout the year. The clothes moth lifecycle consists of four stages: Egg → Larva → Pupa → Adult moth. After mating, females lay eggs close to suitable food sources, the eggs then hatch into larvae. It is this larval stage that causes damage by feeding on materials containing animal fibres and proteins, including wool, cashmere, fur, feathers and other suitable materials. The larvae eventually pupate and emerge as adult moths. Those adults reproduce and the cycle begins again. Temperature and humidity has a major influence on this development and the frequency of moth breeding phases. In warm indoor conditions, development can be considerably faster than in cool conditions. This means you can experience periods where relatively few adult moths are visible or being caught, followed by an apparent sudden increase as another group reaches adulthood. A quiet trap for a period therefore does not necessarily mean every moth has disappeared. There may still be eggs, larvae or pupae developing elsewhere in the property, everything comes to those who wait so if it is indeed the correct moth then please remain patient.
8. Please do not judge the trap after only a few days. Pheromone monitoring works best when you look at the pattern over time. If you put a trap down today and it hasn't caught anything three days later, that alone tells you very little. Adult emergence depends upon the lifecycle of the infestation, temperature and local environmental conditions. Leave the trap in place for the recommended monitoring period and check it periodically. Keeping a simple record can be surprisingly useful: Date installed → location → moths caught → date checked. If catches suddenly increase, decrease or concentrate in one room, that information can help you understand what is happening.
9. Seeing moths but catching none? Work through this checklist:
-
Is it definitely a clothes moth? Small moths are easily confused so check the guide above. Indian meal moths require their specific pheromone traps and Brown house moths and White-shouldered house moths do not have a species specific pheromone trap and require a different approach.
-
Are you using too many pheromone traps in one area? Reduce unnecessary clustering and follow the recommended spacing.
-
Is the trap in placed next to a strong draught? Move it away from open windows, fans, vents and powerful air movement.
-
Are repellents being used nearby? Move lavender, cedar and other strongly scented repellent products away from the monitoring trap.
-
Is the trap positioned near the likely infestation? check around carpets, wardrobes, furniture, rugs and other natural-fibre materials for suspicious activity and damage.
-
Could you be between adult emergence periods? Remember that eggs, larvae and pupae won't be attracted to the pheromone.
-
Is the lure still within its recommended effective period? Replace traps and lures according to the product instructions.
10. A trap with no moths can still tell you something useful. An empty trap isn't automatically a failed trap. For example, if moths are visibly flying around but a correctly positioned fresh clothes moth pheromone trap repeatedly catches nothing, species identification should be reconsidered. Conversely, if a trap catches common clothes moths when you haven't noticed any flying around, it may have detected low-level activity that would otherwise have gone unnoticed. This is why pheromone traps can be so useful not only in reducing numbers overall but simple monitoring and diagnostic tools.
11. Look for the source – not just the adult moths. If your traps are catching clothes moths repeatedly, start investigating the surrounding area. Look particularly carefully at dark and undisturbed locations. Move furniture, check underneath rugs, inspect carpet edges. Look underneath beds and wardrobes, examine woollen clothing, cashmere and stored textiles, inspect upholstery, particularly underneath furniture and around seams, look for larvae, silk webbing, cases, frass (moth poo) and obvious damage to natural fibres. The adult moth caught on your trap is often only the visible part of the problem.
12. Pheromone traps are an important part of moth management – Pheromone traps are extremely useful for keeping numbers down, detection, identification support, monitoring and locating areas of activity. However, if an established infestation is present, successful control also requires attention to the larvae and their food source. This can involve appropriate cleaning, vacuuming, laundering or treatment of affected textiles, investigating inaccessible areas For significant infestations, then professional intervention may be the only appropriate solution.
Thank you so much for scrolling down this far and I hope it has helped. Please contact us if you have any further trap concerns or would like some moth related advice.
We are always happy to help.
ALan
London Moth
