Adult moths may be seen in July and August. They have white wings, a white head and thorax, with a dark brown abdomen which has a tuft of brown hairs at the tip. The female lays batches of eggs which hatch into caterpillars (larvae of the moth) in late August and early September; they are nearly black in colour and have two bright red marks located at the end of their body. The caterpillars spin a silken tent over trees and shrubs under which they shelter during dull weather and at night. On warm sunny days, the caterpillars will leave the silk tent to feed on nearby leaves. The caterpillars may be seen from August to October, then again after winter hibernation, from April to June.
The caterpillars eat buds and leaves of many species of tree and shrub and in severe cases cause total defoliation before they move on to other plants. In additional, and more importantly, the caterpillars carry up to two million hairs which can penetrate the skin causing an irritant reaction. Asthmatics and hay fever sufferers should not inhale the hairs are not inhaled as they may cause breathing difficulties.
What can I do to get rid of them?
You can try and get rid of the caterpillars by cutting the tents out from the foliage and burning them or burying them in the garden. The best time to carry out this work is between November and March whilst the caterpillars are hibernating, but there are risks involved as many of the irritant hairs from the caterpillars are bound up in the tents and can become detached when pruned out. If you do attempt to prune out the winter tents, please be aware of the following guidance:
- Wear strong, protective clothing, preferably garments that can be made tight at the cuffs and ankles and can be either boiled or disposed of afterwards.
- Cover as much bare skin as possible by wearing gloves, a hood, boots, goggles and a mask.
- If you are using a ladder, get someone to hold it steady
- Carefully remove the tents with secateurs from the tree or shrub by cutting the branch or twig to which it is attached
- Either burn the tents if you can do so safely and without causing a nuisance to neighbours, bury in the garden or double bag the tents in plastic bags and seal tightly and put in your refuse bin.
- You are strongly advised not to deal with an infestation if you can are asthmatic, suffer from hay fever, have sensitive skin/suffer from a skin condition, don't have adequate protective clothing or are not comfortable working at heights.
- If the infestation of such a size or location that considerable disturbance of the tents is inevitable, it would be not be wise to deal with the problem yourself and contact a local pest control firm.
- Chemical treatments using insecticides are an alternative way of dealing with the problem and these can usually be purchased from good garden centres. It is important to closely follow the manufacturer’s methods of application and to use protective clothing. If you do not feel comfortable carrying out this work yourself, contact a local pest control firm.
We are unable to recommend local pest control firms, but suggest using a service search engine such as Yell. We advise residents to get two or three quotes to obtain a competitive price.
If you have an infestation in a tree where legal restrictions apply, such as a Tree Preservation Order or it is within a conservation area, please contact our countryside team on 01395 517557.