I've noticed that local garden centres are restocking box plants & if you are tempted to replace any box plants you've lost please read the following information:
Sadly, this relatively new pest to the UK, is now rife in Harringay.
If your box plants have webbing amongst the leaves have a closer look & you may find it.
I see it very frequently in the area & it does eventually defoliate & destroy box plants unless treated:
This video shows how.
The options I would recommend are:
1. Spraying with a biological control:
This would need regular commitment to be effective during the times when the moth is active & would therefore involve some longterm costs.
The commitment would involve regularly inspecting the hedge for signs of eggs & the caterpillars. The cost would be the price of the nematodes & spraying.
2.Removal of the hedge & replacement with an alternative hedge which is not eaten by these caterpillars
Further information available on RHS website.
I discovered these little blighters earlier in the year. My soft heart was repaid with a decimated box bush.
I don't know if the timing of your post is coincidental, but there seemed to be a local mini-plague of these again last night. I had five in my kitchen and more beating at the windows.
Haha! At first I was imagining the caterpillars beating at your windows Hugh,
but then I realised you were talking about the #BoxTreeMoths.
They are still researching how far the moths can fly but I fear it’s quite likely they will
slowly spread throughout the UK - extremely sad when you think about all the beautiful
topiary & hedging we have here.
I was softhearted too & tried to pick them off at first but I couldn’t keep it up as they are
so hard to spot when they first hatch.... I ended up resorting to spraying with the biological
control & managed to save my plants - for the time being
I had my box plants in Tottenham badly damaged last year and managed to get a hold of some bio control in the spring this year and sprayed. The plants never looked better. But it does mean you have to religiously check and spray.
Bio-control powder was hard to get in small quantities here in the UK and triple the price than on the continent by the way! Exactly the same product!
Thanks for this info Sally. Our box plants all look finished and I was wondering why this had happened.
You're welcome Justine. I'm sorry you lost all your plants.
So many folk presume they've lost their plants due to the drought this summer & will replace their box -only for the same thing to happen
Unfortunately not enough people know about it & are unwittingly perpetuating the problem.
Are you sure the plants are dead? If it is a hedge, I inspected them and removed as many pests I could find and left the plants to over winter but managed to spray the bio control this spring as soon as weather permitted then they regrew the foliage after a good clipping. Now look as luxurious as ever and I just need to keep on top of the spraying.
PS I believe that the bug doesn't only attack box plants.
That’s great news you got your box hedge to grow back.
I haven’t heard of the caterpillars eating any other plants but they do overwinter:
“It overwinters as small caterpillars, hidden between box leaves that have been spun together with silk in autumn, and completes its development in spring”
More info here
Thankyou that is very interesting
“Although Euonymus japonicus and Ilex purpurea are mentioned as host plants in Japanese literature (Straten and Muus, 2010), there are no reports of these plant genera being affected in Europe. Unpublished trials by the plant protection Service of the Netherlands also ruled out other Buxaceae as host plants (Straten and Muus, 2010). However, it is possible to rear C. perspectalis on an artificial diet, mixed with dried box tree leaves (Kawazu et al., 2010)”
A quick look in a box bush found 3 pupa;
This site is useful https://www.ebts.org/2016/05/box-tree-moths-plague/
Nice info Matt.
The fluffy green specks in the bottom of the pic are the caterpillar's poo - another way to spot them!
I also use a pheromone traps to trap the male moths - that gives me the signal to start searching my plants.