Brown tail moth
Over the last few years Brown Tail Moth infestations have increased - especially in the southern parts of the UK - and they have been seen in the Exeter area.
The caterpillar is a voracious eater of vegetation, especially in the spring, and although it prefers hawthorn and blackberry, it will eat practically any type of tree or bush. Heavily infested trees are weakened by the loss of foliage, consequently growth is poor and fruits fail to mature for several seasons which is a problem for the gardener.
What do they look like?
The caterpillar is blackish grey in colour with tufts of ginger brown hairs and two orange spots near the tail and the moth has greyish white wings with a brown tail.
During cold winter months when the trees are bare the caterpillars hibernate in greyish silken "tents" usually found at the tips of branches. In Spring as the weather becomes warmer they leave the tents to forage for food.
Life cycle and control measures
Please Note: The caterpillars have small toxic barbed hairs all over their bodies, which can break off easily and irritate the skin - in some cases severely. Some people can suffer a type of asthmatic reaction
May and June
The caterpillars emerge particularly during warm weather and can be treated when they are out of their nests using a chemical spray. The most suitable and widely available chemical is called a Pyrethoid and is sold under various names at garden centres and DIY stores. It is not effective when the caterpillars return to their nests in the evening and during bad weather. At these times it is much better to physically remove the nest using secateurs to cut them and drop them into a plastic bag which should be sealed and either burnt, if it is safe to do so, or sealed in a second plastic bag and put in the dustbin.
September and October
The caterpillars re-emerge and although not so apparent as in the spring, their feeding will cause leaves at the top of the tree or shrub to turn brown. They can be very effectively dealt with by the methods described above.
They stay in their tents and as the leaves drop these become very visible. The tents can be cut out at this time of the year but the insecticide spray is largely ineffective.
How do I get rid of an infestation?
Please read the following carefully before attempting to remove an infestation.
There are a number of precautions you should always take when carrying out a treatment.
Always wear thick clothing, rubber gloves, wellington boots and as far as possible cover all bare skin. If you are spraying insecticide follow the manufacturer's instructions and recommended safety measures. Always spray when the weather is fine and there is no wind or rain to avoid drift or run-off problems. It is also advisable to wear goggles. If you are using a ladder, either lash the ladder to the tree or get someone to stand at the foot of the ladder. Protective clothing should be thoroughly rinsed in clean water after use as the irritant hairs will adhere to it.
Suggested treatment for irritation
Minor skin irritations should be washed immediately with hot soapy water and calamine lotion applied as necessary. Serious or persistent symptoms, for example hairs penetrating the eyes or being inhaled, should be seen by a doctor.
This information is provided for advice only. The Council does not provide a treatment service to remove affected leaves or caterpillar "tents" from private property. However, some commercial pest control companies may provide a treatment service for a fee.