Posted: Monday 29 July 2013
by James Alexander-Sinclair
Do you recognise this? If you grow viburnums, you may well have suffered at the hands of this little grub. It is the offspring of the viburnum leaf beetle...
Do you recognise this? If you grow viburnums, you may well have suffered at the hands of this little grub. It is, of course, the offspring of the viburnum beetle (Pyrrhalta viburni), and is capable of thoroughly perforating a viburnum leaf in a distressingly short space of time.
Skeletonising is, I believe, the correct term for this. It transforms healthy leaves into the foliage equivalent of all those ghostly semi-dead warriors in The Lord of the Rings (the ones that whoosh in and save the bacon of various hobbits, and Viggo Mortensen, when they are in the soup at Minas Tirith, or somewhere like that).
At particular risk is Viburnum opulus, which is a very pretty native shrub, with white pom-pom flowers, followed by red berries in the autumn. Also, Viburnum tinus, which is a tough evergreen with leaves as leathery as a gaucho’s thigh.
The viburnum beetle is a rather handsome number, with a shiny, olive-coloured carapace. The grubs hatch out in early spring and set to work, almost immediately, on shredding viburnum leaves. Then they pupate and carry on nibbling duties as adults. These adults then lay eggs that overwinter in the bark crevices, before the whole thing begins again the next spring.
You will want to know how to get rid of the little blighters. Sadly, it’s not very simple. You can spray the shrubs in spring and again in summer, but I am afraid that the infestation may well return if your viburnum-growing neighbours may well not be as fastidious as you.
You can also pick off the grubs, but there are lots of them so you will need to have a lot of spare time (and good eyesight). Or, you can do some serious cutting back of your viburnum and burn the prunings. Doing this may well help, but will also ensure that you have no flowers next year.
It is a tricky one. The best suggestion I can give is that if it really bugs you (unintentional bad pun, sorry) then grow something else.
29/07/2013 at 17:49
Hi James my Viburnum Tinus looks like a net curtain,I would have thought the birds would have taken the grubs to feed there young but sadly not,maybe they don't taste good,Oldchippy.