The reality about treating Buxus re: Caterpillar damage and Box blight from the Topiarist

The reality about treating Buxus re: Caterpillar damage and Box blight from the Topiarist

There has recently been several articles written about box referencing academic research and I would like to give a practical take on these articles, as a hands on professional with 30+ years experience of growing, cutting and restoring topiary.

During my travels I see many gardens with various Buxus problems, from blight to the latest challenge – the Asian Box Moth / Caterpillar (Cydalima perspectalis) – and many confuse the two problems. The first signs of caterpillar damage are nibbled leaves, webbing (similar to spider) and caterpillar green excrement at the base of the plant and defoliation of leaves. Whereas Box Blight (Cylindrocladium buxicola) is black spotting on the leaves, defoliated leaves and bald patches, i.e. in the top of hedging. I would like to emphasis that both are treatable by professional and retail products.

If you are, or know of, a professional licensed sprayer, you can use Decis for the caterpillar (Cydalima perspectalis). The retail product is Provado by Bayer. There is also a new product which I have not yet tried, but have excellent reports of, by TopBuxus called Xen Tari.
For the organic gardener – Steinernema carpocapsae are pathogenic nemotodes that attack caterpillars and laboratory studies have shown that they will kill the Asian Box caterpillar, but effective control is reliant on high humidity levels around the leaves. The only known natural enemy of the caterpillar is the Asian hornet – which have already entered the UK borders!! Maybe following their food source!

Unlike comments from TV personalities, birds will not touch the caterpillars as they are toxic to birds as a result of eating box (Buxus).

For box blight we recommend TopBuxus Health mix or Bayer Fungus Fighter Plus, both have excellent results. In my field stock I grow many varieties of Buxus, including Microphylla Faulkner, and all are equally susceptible to box blight. Mulching underneath box with either ornamental bracken mulch or for larger area of box, use straw. The idea behind this is stopping the spores of the fungus bouncing back on to the plant when it rains.

My field stock consists of over 2,000 plants, mainly Buxus. I also grow, Yew (Taxus baccata), Phillyrea angustifolia and latifolia – I prefer latifolia for its darker leaf, both are good an contrasting colours, however, it does like to be a big plant, 2m upwards. Many journalists recommend Ilex crenata, I have attempted to grow it but I find it a very fussy plant and have stopped growing it. Alternatives to box will need much more cutting. The reason Box and Yew were traditionally used is because they only need cutting once a year.

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Topiary tuition at Missenden Abbey 2017

Residential Course at Missenden Abbey – 24th & 25th August 2017

  •  Suitable for all age groups & all levels of expertise from garden enthusiasts with a passion for being creative with Topiary to Students who are studying garden design or horticulture, wishing to further their knowledge in a specific area of expertise.
  •  The format of the supervised “hands-on” workshop will give students a chance to demonstrate their creativity working with their own un-cut Buxus plant, with one to one guidance and tuition with James, encouraging design inspiration – you get to keep your newly shaped Topiary plant!!
  •  Please bring suitable clothing for outdoors.

The Topiary Tuition Day with James

  • Practical demonstration of Topiary
  • Technique and cutting
  • Inspiration of Topiary in the garden setting from embryo plants to finished Topiary
  • Tips on care and maintenance + pests and diseases
  • Shortcuts to creating good strong shapes
  • Presentation and discussion on Topiary
  • Hands on workshop and your own plant to take away.

Programme to include:

  • Residential course at Missenden Abbey
  • 3pm Arrival for afternoon tea and check into your accommodation
  • 5pm Welcome talk with James Crebbin-Bailey
  • 6pm Welcome drink with James followed by dinner
  • Overnight stay with full English breakfast
  • Topiary tuition day
  • Lunch
  • Practical hands on session
  • Depart after tea.

Topiary Arts Booking Form 2017

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James’ talk at West Dean College – 29th April 2017

Enjoy a talk about the history of topiary and a practical demonstration on cutting techniques. Gain inspiration for topiary in garden settings, from embryo plans to finished topiary and take home tips on care and maintenance. Followed by a hands-on slotspie workshop to create your own plant to take away.

See West Dean College website for more details, click here.


Box Tree Moth Infestation can be Controlled says James Crebbin-Bailey.

Box Tree Moths (Cydalima perspectalis), which devastated Buxus topiary plants in and around London in the summer of 2015, should not be such a problem this summer provided plants are sprayed regularly, according to topiary expert James Crebbin-Bailey of London based Topiary Arts.

Dr Hayley Jones, an entomologist with the RHS, discussing the Box Tree Moth infestation on the BBC in 2015 said: “The live roulette online key thing is that it is established – it has survived throughout the winter and is breeding, it has a foot in the door and is increasing in numbers”.

It is not the Moth itself which causes the damage, but the caterpillar, which mutates from the larvae laid by the moth. This inch long pest spread rapidly beyond the M25 and into Essex during the summer of 2015. Previously it was only found in parts of South West London. In 2011 just three reports were recorded by the RHS, with 20 in 2014 leaping to 150 last year.

Box Tree Caterpillar infestation It is anticipated that there could be an explosion of Box Tree moths in the spring this year due to the relatively warm winter we are experiencing.

The picture on the right shows the devastation of a Buxus Ball caused by a Box Tree Caterpillar infestation leaving a matted webbing effect on the outer sides and a mass of green excrement round the base. Since this picture was taken the plants have been sprayed with Decis by professionally qualified sprayers and are recovering.

buxus ballNow about six months later in February 2016 we are encouraged to see that most of leaves have grown and the plant appears to be fully recovered, says James Crebbin-Bailey. We will continue to do a programme of spraying at 6-8 monthly intervals, depending upon how the season pans out.

What does the moth and caterpillar look like?

The adult moth has white, slightly iridescent wings with a dark brown band at the outer margin and a characteristic white spot on the forewing. The wing can also be brown or partly brown. The wingspan moth-and-caterpillarcan reach 4cm. They are good flyers, although the distance they travel is not known. During the day they can be found resting on Buxus or surrounding plants. They are sensitive to disturbance and may fly during daylight if the plant they are resting on is shaken. The moth is highly adaptable to different environments and is tolerant of shade. Adults reach a lifespan of up to 2 weeks. There can be between one to four generations per year.

The female moth lays white-yellowish translucent egg clusters deposited on the top and under side of box leaves, consisting of 5-20 eggs that are very difficult to spot. One single egg cluster can spread over an area of 20-30 cm diameter on a box plant. Once hatched, the caterpillars box-tree-caterpillarsare characterized by black stripes with white dots on a light green body with hairs and a shiny black head.

The caterpillars feed on the leaves of Box trees, resulting in defoliation. They can attack the bark of box trees causing them to dry out and die. An infested hedge can contain several hundred of the caterpillars, which leave a ghostly trail of sticky webbing in place of the foliage and creating leaf skeletons.

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Taking control

Pheromone traps are essential for every garden with box / Buxus.  They are the first line of defence as they are a good indication of whether or not you have Box Tree Caterpillar. If you find the Cydalima perspectalis moth in the bottom of the trap you will need to check your Buxus plants for signs of egg clusters and caterpillars. If a mail moth enters your garden you need to capture it to prevent it from breeding. If a female moth enters it is likely it’s too late, as she will lay eggs on the box leaves.

The pheromone traps contain a lure, which is placed in the upper section of the trap and a small amount of water is put in the bottom, to prevent the moth from escaping. The lure will attract the male moth. There are four lures that come with each trap which need to kept cold, or frozen until use. Each trap covers an area of 0.4h (just under an acre) and each lure will last 5-6 weeks depending on infestation in your area. James explains that he can supply the Pheromone Traps £33.00 + £3.00 p&p.

What to do when you see the caterpillars

Spraying – Mixed opinions – you cannot spray as a preventative. Bacillus thuringiensis is a parasitoid that acts on small larvae causing muscular paralysis when they start nibbling the box leaves they will be ingesting the pesticide. Biopesticides based on Bacillus thuringiensis are usually the preferred option due to their limited impact on the environment. Products such as Bayer Provado can be purchased from most garden centres or stores and will need to be applied to the Buxus every 10 days.

A professionally qualified sprayer will use Decis, this acts on contact with the caterpillar. This will need to be carried out at 6 week intervals throughout the season – end of March to October. The season varies according to climatic conditions.

Physical control by cutting off infested material, picking off eggs or caterpillars, is also effective.  However, feeding the caterpillars to birds is unlikely to be successful due to the toxic levels of Buxus ingested by the caterpillar – what is tasty to the caterpillar is not so for the birds.

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The natural enemy of the caterpillar and moth (Cydalima perspectalis)

Wasps and Asian hornets are considered to be the natural enemy of the caterpillar and have been observed to prey on the larvae and birds on the moth. However, predation by birds is low, probably due to the high levels of toxic alkaloids digested by the larva.

Nemotodes: Steinernema carpocapsae are pathogenic nematodes that attack caterpillars. Laboratory studies have shown that they will kill Cydalima perspectalis, therefore they have potential for control of this pest, but effective control is reliant on high humidity levels around the leaves. S. carpocapsae are available for gardeners (as Nemasys) and to professional growers (as Capsanem).

For box plants in gardens, insecticides containing pyrethrins (Pyrethrin is synthetically made by industrial methods, but it also naturally occurs in chrysanthemum flowers) should be effective against the caterpillars.

Lastly, states James, an important point is to try and protect the box plant by strengthening its immune system – Feeding and we also use Effective Micro-organisms (EM). EM consists of the following five families of micro-organisms: Lactic acid bacteria, Yeasts, Actinomycetes, Photosynthetic bacteria and Fungi that considerably improves the quality and fertility of soil as well as the growth and quality of plants.

At the end of the day says James, this is just another spraying routine for a plant and if we are all vigilant and take measure to help eradicate this pest, we stand a better chance of saving our heritage gardens, as well as our carefully grown Topiary.

James Crebbin-Bailey, Topiary Arts

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James Crebbin-Bailey
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PHEROMONE TRAPS for Box Tree Caterpillar / Moth / Cydalima perspectalis

Box Tree Caterpillar Pheromone Traps for Sale

The cost is £33.00 per trap (+£3.00p&p) – See buy online option below

Each trap contains 4 ‘Lure’s’ that last for a period of 6 weeks / 4 Lures will last the season April – October

Each trap covers an area of 0.4h / just under an acre. We are suggesting that if Buxus (box) is in front and back of a property, you will need 2 traps.

Order UK – Includes Postage Order Europe – Includes Postage

Select number of traps UK

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Pheromone Trap Refills (1 Pack contains 4 Lures)
Each lure lasts 5-6 weeks, so about one season for trapping the Box Moth
£16.50 + £1.50 delivery UK
£16.50 + £4.00 delivery Europe

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Too many box tree caterpillar traps apparently confuses the mail moth!!

The ‘Lure’s’ last for 6 months out of the fridge but in a cool store / 1 year in fridge / 2 years in freezer

If there is a problem and you can see evidence of the Box moth / caterpillar (Cydalima perspectalis), then you can purchase Bayer Provado from any garden shop, alternatively if you can ‘professionally’ spray, then Decis is recommended.

View BBC News Box Tree Caterpillar Information Video

Daily Mail Box Tree Caterpillar Article.