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Beware of processionary caterpillars

A DANGEROUS grub that is out in force at this time of year across the Algarve is the processionary caterpillar, which can be harmful to both humans and animals.

The processionary caterpillar is the larva (prestage) of a type of silk producing moth called thaumetopoeiae.

The grubs live in large communal nests, known as bag nests, which hang from tree branches, most commonly in pine trees feeding from the tree’s needles.

When they have exhausted one tree, they move on to another, forming a line of up to 50 caterpillars.

They have a poison that covers their outer fine hair and this acts as protection against enemies that try to eat them. In the case of inquisitive pets, the acid from the poison can result in the loss of their tongues so it is important to keep an eye on them.

In humans, the fine hairs release histamine in the skin and can cause an itchy rash. Blisters can also form. The most commonly affected areas are neck and legs.

Histamine can, in a worst case scenario, trigger asthma attacks and even anaphylactic reactions.


Teach children not to touch the caterpillars.

Cover head and neck while near pine trees.

Use lots of moisturiser all over your body.

Take a shower and change clothes after being near pine trees.

Annual sufferers should consider taking an antihistamine when the season starts.

If you have a bad rash, see your doctor sooner rather than later.

Should you have lots of pine trees, you could have them treated with a responsible pest agent against the caterpillars.

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