Box Tree Moth Cydalima perspectalis
The Box Tree Moth is a beautiful white moth, of which the edges of the wing are black. Some animals also have one or more black lines and patches within the white part of the wing. And to complicate matters even more there are specimens which are all brownish black, sometimes with very small white spots. This is a big species, for it reaches a wingspan of 40 to 44 mm, which means it is as big as the Map.
The Box Tree Moth originates from Eastern Asia (Japan, Korea and China) and was introduced in Switzerland in 2006 or before. It turned out to be a very invasive species. Already in 2007 it turned up in the Benelux countries and one year later in Britain. By now it has conquered Greater London and surrounding areas and is still spreading. In Europe it especially attacks the Box Tree (Buxus sempervirens), a plant that even doesn't grow in its original area. It is however also found on other plants such as Black Mulberry. It is a devastating species on Box Tree. The main problem is that the species is double-brooded. The first brood starts eating Box Tree leaves in April and May. This may defoliate the Box Tree, but it is not fatal as some 6 to 8 weeks later the Box Tree will produce new fresh leaves. These however are eaten by the second brood appearing in August mainly. The second brood is then fatal to many Box Trees. Many gardeners have already gotten rid of their Box Trees alltogether. However this development may slow down or even halt in the near future as many predators have discovered the caterpillars to be a good source of food. Especially jackdaws, various titmice and sparrows are enjoying this great food source.
The caterpillars are yellow when young, but soon turn bright green. They have several black warts surrounded by white circles. They may reach a length of some 40 mm. The second brood is more numerous than the first, but both broods partly overlap. Fully grown caterpillars overwinter in a self made cocoon, either in a Box Tree plant or on the ground. They are capable of surviving even the coldest winter.
Widespread in Europe and Eastern Asia. A real pest in London and surrounding areas, spreading rapidly further into the UK.