Cydalima perspectalis, or as it’s better known, The Box Tree Moth (sometimes called Box Worm Moth), is a non-native species belonging to the family Crambidae. Which also includes the so-called Grass Moths. This is a large Family with 140+ species recorded in Britain alone.
A medium sized moth (very large for a micro-moth) with a 40mm wingspan(1). This is one that can be identified easily in the garden/wild with a good photograph and reference material. In other parts of Europe it has two or more broads a year but it’s unclear how many in the UK.
It’s place in the Garden (Visitor)
The larva/caterpillars (often called worms by gardeners) feed on Box leaves and shoots. In the local area there is a good amount of Box, often used on new housing developments, and the impacts of this species has been significant. We tend to see the adult visiting the garden around September time, but only since 2021. As we have no larval food plants and are unlikely to plant box it will remain just a visitor.
It’s not yet clear what native species may prey upon this Asian invader. According to wikipedia some areas of Europe where the Asian hornet has established there is perhaps some form of natural control. But Asian Hornets come with their own set of problems and most people in the UK are likely to look towards chemical control.
How to encourage the species to your garden
Probably not applicable. The species has been in the UK since 2007 and has spread from the Southeast where it was likely imported on a Box plant. We’ve not seen one come to the moth trap but its early days yet as its only just arrived in our part of the country.
- UK Moths: Species Account Page. https://www.ukmoths.org.uk/species/cydalima-perspectalis/ – Accessed online 21st December 2022
- Sterling, P & Parsons, M (2012): Bloomsbury Wildlife Guides: Field Guide to the Micro moths of Great Britain and Ireland. Bloomsbury Publishing Ltd