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Do box tree moth traps work?

Updated: 22 October 2026

The bucket is full of moths and the box hedge is still browning from the inside. That is the usual week someone asks whether a box tree moth trap works. It works as a monitor of male flight. It does not catch the caterpillars, and a full bucket is not proof the females have stopped laying. This page is that limit, from the Royal Horticultural Society and from Defra, not a ranking of kits. Prices and badges are on the [box tree moth trap comparison](/hub/pest-control/box-tree-moth-trap). Water depth and hang are on [how to use a box tree moth trap](/hub/pest-control/box-tree-moth-trap/sub/box-tree-moth-trap-how-to-use). Products Compared, 21 October 2026. We did not run a catch trial. A qualifying purchase can earn a commission at no extra cost to you.

The bucket is full of moths and the box hedge is still browning from the inside. That is the usual week someone asks whether a box tree moth trap works. It works as a monitor of male flight.

Our top picks

IPM Direct IPM Direct box tree moth trap

Best overall

IPM Direct IPM Direct box tree moth trap
8.2/10about £18.99
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COMPO COMPO boxwood moth trap

Alternative

COMPO COMPO boxwood moth trap
7.7/10about £29.57
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SWISSINNO SWISSINNO box tree moth trap

Best value

SWISSINNO SWISSINNO box tree moth trap
5.3/10about £15.37
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On this page
  1. 1.What the trap catches
  2. 2.Why that is not control
  3. 3.Full bucket, empty bucket
  4. 4.What still has to happen in the garden

What the trap catches

The lure is a pheromone for male box tree moth, Cydalima perspectalis. Males follow it into a funnel and, on the usual design, into a few centimetres of water with a drop of detergent. You can see that males were flying beside that bush that week. You cannot see females in the same bucket, or the caterpillars, which stay on the plant. Defra’s June 2024 factsheet describes the larva growing to about 4 cm. People find them by parting the leaves, often inside webbing. The RHS puts pheromone traps in the “are moths active?” column. Suppliers it names include Agralan, Dragonfli, and Solabiol. Naming a supplier is not a score for a listing. Seller pages often say that catching males reduces egg-laying. That sentence is ahead of the 2019 RHS review. Fifteen moths in the water is a reason to look harder at the foliage. Caterpillars already hatched are untouched.

Why that is not control

The 2019 RHS review says traps are unlikely to give overall control because only males are attracted. Females that have already mated ignore the lure and carry on laying. If one or two males remain, mating can still happen. The review points to van der Straten and Muus (2010), who did not get satisfactory control from pheromone trials. That sits beside any title that says the trap stops the next generation. EBTS UK restates the same position: the trap is for monitoring. Funnel traps in the SaveBuxus account caught males better than sticky traps and still did not stop damage. A many-trap layout in Val-de-Marne still left the box defoliated by autumn 2016. Those figures are that French report, not a percentage for a UK hedge. Mating disruption is professional dispensers, not one lure in a garden funnel.
IPM Direct IPM Direct box tree moth trap

Testsieger

IPM Direct IPM Direct box tree moth trap
8.2/10about £18.99
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Full bucket, empty bucket

A full bucket means males were flying and the lure was still attractive enough for them to enter. It does not mean every male was caught, or that females failed to lay. Gravid females are not drawn in, and a few males are enough for mating, so you can have a busy trap and new webbing in the same fortnight. Search the leaves, including the interior of a tight hedge. An empty week in April does not clear the garden. Flight comes in bursts, and females were never the target. A seller may print 180 square metres or one trap per half an acre. Those are sales lines. One funnel samples the air beside the plants you hung it on. Power-washing larvae out is a separate mistake: the 2019 review links it to damage on box and to box blight.

What still has to happen in the garden

On a small bush, Butterfly Conservation’s April 2024 note and the RHS both put hand removal ahead of spraying. Part the leaves, pick the larvae and the pupae, and use the trap to know which weeks are worth another search. A long hedge or a topiary you cannot open is where a weekend of picking stops being realistic. Then the trap remains a sample. If you move to a spray, the trap has only told you the moth is present. The Health and Safety Executive says the user of a pesticide is legally responsible. This page will not name a current home authorisation. A 2019 line on Bacillus thuringiensis is too old to treat as today’s rule. The RHS mentions a mixed nematode, Fruit and Vegetable Protection, with some effect and a warning about non-target animals. That is not one of these traps. Defra’s June 2024 factsheet says this pest is not notifiable. Do not post a catch to the Animal and Plant Health Agency. For a first monitor, use the box tree moth trap buying guide or the best box tree moth trap page.

Common questions

Does a pheromone trap kill the caterpillars in the hedge?
No. The lure attracts adult males. Caterpillars stay on the leaves, often in webbing, and Defra’s 2024 factsheet describes a fully grown larva of about 4 cm. A bucket of moths does not remove larvae that have already hatched.
If the bucket is full, can females still lay?
Yes. The 2019 RHS review says gravid females ignore these traps and keep laying, and that one or two males can be enough for mating. A full bucket shows males were flying. It does not show that egg-laying has stopped.
If the bucket is empty, is the garden clear?
No. An empty week is inconclusive. Females were never the target, and male flight pauses in cool weather. The RHS warns that females can arrive in May and lay even if the first generation missed your bush.
Will one trap protect 180 square metres?
No. That figure is a seller’s line, also printed elsewhere as half an acre. It is not a British Standard. One trap samples male flight near the plants you can inspect.
Should I report a catch to Defra?
No. Defra’s June 2024 factsheet says this pest is not notifiable. Do not send moths or caterpillars to the Animal and Plant Health Agency to report box tree moth. If you suspect a different, unknown plant pest, use the usual routes: APHA in England and Wales, the Scottish Government, or DAERA in Northern Ireland.
Is a garden trap the same as mating disruption?
No. Mating disruption, as EBTS UK describes it, is a professional dispenser layout, not one lure in a domestic funnel. A garden trap catches some males that enter it. It does not replace searching the foliage.

Related pages

Box tree moth trap

Best box tree moth trap: the top pick and who to skip

Box tree moth trap buying guide: kit versus refill

How to use a box tree moth trap in a British garden

Box tree moth pheromone refill packs for a used trap

Sources

Public UK sources used for this comparison. Shelf prices, stars and review counts are the amazon.co.uk figures captured for these twelve listings. Last checked 20 October 2026.

  1. RHS, Box tree caterpillar (retrieved 20 October 2026)
  2. RHS, Box tree moth review (2019 PDF) (retrieved 20 October 2026)
  3. Defra, Box tree caterpillar factsheet, June 2024 (retrieved 20 October 2026)
  4. Butterfly Conservation, Box moth policy note, April 2024 (retrieved 20 October 2026)
  5. HSE, Pesticides in the garden and home (retrieved 20 October 2026)
  6. Andermatt UK, How to monitor box tree caterpillar (retrieved 20 October 2026)
  7. Dragonfli, Box tree moth trap lure PDF (retrieved 20 October 2026)