The control and treatment of the brown tailed moth is generally not an environmental health issue and the Council does not provide a treatment service. If you require treatment we advise that you contact a private pest control contractor.
The Brown Tail Moth is found in considerable numbers along the coast of South Eastern England and is usually active from late spring to early June.
What makes the Brown Tail Moth Caterpillar a pest?
The caterpillars appear in spring and begin to eat the buds and leaves of trees and shrubs. They may leave the plants bare but most plants will regrow leaves by July. The caterpillars carry up to two million spiked hairs, which can leave the skin sore or cause a rash For people with asthma or hay fever the hairs may cause breathing problems.
How do I know if I have them on my property?
You may notice the caterpillars in the winter after the leaves fall. Their nests look like silk tents that are attached to small branches in the middle of your tree. They may contain up to 2000 caterpillars.
From spring the caterpillars become active and may be seen on the branches of trees and shrubs. They are between 7mm and 38mm in length (depending on age) and are dark brown in colour with a white line down each side. The whole body is covered in tufts of brown hairs and two orange/red dots can be seen on the caterpillars back towards the tail.
How should they be treated?
You should avoid touching the caterpillars and in cases of large numbers it would be wise to keep windows closed to stop caterpillars entering your house. The best way to treat any infestation is by cutting out and burning the tents during the autumn/winter period when the caterpillars are inside. During the summer months when the caterpillars are active, contact chemical sprays may give some control, but as only some of the caterpillars leave the tents at most times, this is not an effective option. What is needed is a residual poison which can stick to the leaves of the tree so that as the caterpillars go out the means of control is in place to get rid of them.
Can I treat them myself?
Yes, but there is a risk of doing so and you must be careful. The tents contain many of the caterpillar hairs and can be easily be spread when these are cut out. If you are uncertain of the chemicals to use and are not aware of the safety and application requirements, do not try to use chemical control. Various pesticide products are available from most good garden centres where further advice can also be found. It is important to closely follow the product maker’s methods of application and to use protective clothing fully.
If attempting to prune out winter tents:-
- Wear strong, protective clothing, such as those that can be made tight at the cuffs and ankles and can be either boiled or disposed of after use.
- Cover as much of your bare skin as possible by wearing gloves, a hood, boots, goggles and a dust mask.
- If you are using a ladder, get someone to hold it steady.
- Carefully remove the tents from the tree or shrub by cutting the branch or twig to which it is attached.
- Burn the tents if you can do so safely and without causing a problem to neighbours, or
- Place in plastic bags (one inside a second), seal tightly and put in a refuse bin.
You are strongly advised NOT to attempt to deal with an infestation if you
- are asthmatic
- suffer from hay fever
- have sensitive skin
- suffer from eczema
- do not have adequate protective clothing
- are not comfortable working at heights.
If the infestation is large or in a difficult location, it would not be wise to deal with the problem yourself.
What if I get a rash?
Avoidance is far better than cure and following the previous advice will help to ensure that you are not affected. If you are unlucky to come into contact with the hairs, you can expect a rash together with something similar to a severe nettle rash. Normally this may give up to a few hours of discomfort, a warm bath, the application of calamine lotion or antihistamine creams may ease the itching. If you have any other symptoms or the irritation persists, you should get medical advice without delay.
If you are a tenant contact your landlord or managing agent. In extreme situations the Council may assist with treatments, but a charge will be made to fully recover the costs which could be expensive.
If you have an infestation in a tree on which there are legal restrictions such as a Tree Preservation Order or Conservation Area, you are recommended to gain advice from a tree specialist before taking any action.