20 July 2026

Dealing with Box Tree Caterpillars / Moths attacking box plants / topiary.

If your box plants have turned brown, the leaves are dying and there is webbing on the plant, check for Box Tree Caterpillar. Box Tree Caterpillars have a devastating effect on box plants. They feed on the box plants leaves causing severe defoliation and produce large amounts of webbing. They over-winter, as caterpillars hidden between leaves that have been spun together with silk ready to emerge as moths when temperatures rise – normally in March. Once they have emerged, they will quickly reproduce to produce the next generation of caterpillars. As the caterpillars feed, areas of dieback may appear, which will be especially apparent on trimmed plants. In the spring, the moths appear and there can be up to 3 generations of caterpillars / moths a year.

Box Tree Caterpillars are greenish-yellow with black heads and once fully grown the caterpillars reach up to 4cm in length and will have a thick black and thin white stripes along its body.  Adult Box Tree Moths has up to a 4cm wingspan and it usually white wings with a brown border around the wings, although the moths can sometimes be completely brown. Box Tree Caterpillars over-winter as caterpillars rather than as moths, hidden between leaves that have been spun together with silk and will then emerge in the spring as moths to reproduce and produce the next generation of caterpillars. There can be up to 3 generations of caterpillars a year.

If you discover Box Tree Caterpillars on your box plants, you can use Box Tree Caterpillar Nematodes / Rock Dust to target the caterpillars them selves while a Pheromone Box Moth Trap should be used to attract and catch the moths :-

• Box Tree Nematodes – Use these Box Tree Caterpillar Nematodes (containing a unique mix of different nematodes called NemaMix) to control Box Moth Caterpillar on your box plants. These nematodes are safe to use and will not harm pets, children, wildlife or bees. Box Tree Caterpillar Nematodes need a minimum temp of 12°c and are a perishable product, so order when you are ready to apply i.e. when the caterpillars are 1st spotted – normally between March and October. We supply 3 sachets of F&V Nematodes, which are applied 3 times at 7 day intervals. Supplied in sachets as a powder, it is mixed with water and applied with a sprayer treating up to 50sqm– to treat a smaller area just make the solution stronger as it is impossible to overdose. Box Tree Nematodes are a living, perishable product (it will keep for 2 weeks in the fridge), so order when you are ready to apply and the caterpillars are present. Each pack treats 50 sqm.
• As featured in the European Box Tree Societies Magazine – Use Volcanic Rock Dust to control Box Tree Caterpillars. Rock dust is used commonly to improve soil fertility, but now it has been discovered that dusting you box plants with rock dust when caterpillars are discovered and then twice a year in April and July not only controls the caterpillars, but helps the plants to recover after they have been attacked. Application is simple. Shake the dust all over the plant either by hand or with a sieve (wear a mask) making sure the leaves are covered (on all sides and within the plants). This will initially give the plants a grey dusty appearance, but this will go once it rains, but the effects will stay giving long-term control. Apply a few handfuls per sqm, so a 3.5L bag should treat approx 10 sqm of box plants / hedges. 
• Use the Box Tree Moth Trap to protect your box plants if you know there are moths in the area or position to monitor moth activity in your area. Each trap is supplied with our unique SEASON LONG pheromone lure – the Ginko Buxus lure we include will attract moths for around 240 days unlike our competitors lures, which only last for approx 6 weeks, so it works out much better value for money in the long run PLUS you do not have to remember to change lures every 6 weeks! The lure is added to the top of the trap and secured with the tie included. The trap is designed to be re-usable, so a replacement lure can be purchased the following season and the trap re-used. Each Box Tree Moth Trap comes complete with 1 seasons worth of lure.

Please visit CLICK HERE to find out more about our full range.

Apply Topbuxus Grow Fertiser – For healthy green, blight free box trees / hedges/ balls and topiary apply TopBuxus GROW Fertiliser. Box plants have been under attack from both box blight (a fungal disease, which causes leaves to go brown and fall off) and Box Tree Caterpillar (these caterpillars feed on the leaves leading to bare patches), which makes the plants unsightly. TopBuxus Grow Fertiliser has been specifically developed by a buxus grower to encourages healthy, green growth and to help plants recover from attacks. 

Apply TopBuxus Grow Fertiliser around the base of your box trees / hedges/ balls / topiary at a rate of 50g per sqm 3 times a year to encourage healthy green, shiny new growth. TopBuxus Box Tree Health Mix is a fast-absorbing mineral fertiliser on a 100% natural base. Aim to apply at least 3 times a year in April, June and August when the plants are actively growing and need extra nutrition. This fast acting fertilser is quickly absorbed by the plants without the need for lots of watering, which would increase the risk of box blight. Available in 2 sizes – buy a 500g tub treats up to 10 sqm or a 5kg tub, which treats up to 100 sqm. 

Available to buy now