Processionary Caterpillars, the larvae of the Pine Processionary moth,(Thaumetopoea pityocampa), usually start emerging February to April onwards.  So by March they will typically be getting their marching in full swing. However with the mild winters we’ve been experiencing in their range in Southern Spain, processions are being spotted in some parts a lot earlier, frequently as early as December and January.

These infamous Processionary Caterpillars, get their name from their behaviour of leaving their feeding spots in pines trees, in procession, to find suitable places on the ground to burrow for their pupation stage.  The hairy caterpillars start life as eggs laid by Pine Processionary, a moth who’s life spans just one day.  The caterpillars are sociable and as they grow, together they build nests that look like big clumps of cotton wool high up in the pine trees.

At this stage they a generally harmless, apart from stripping the poor pine trees of their needles, as they are high up out of reach of the pets and children that they are notoriously dangerous too.  It is when they reach maturity that they become the biggest, as it is then that they come down from the trees en mass, right under the noses of curious dog’s cats and children.

The Processionary Caterpillars hairs are poisonous, and when touched cause serious irritation and swelling.  The poisonous hairs detach from the skin of the caterpillar, and if inhaled can cause severe respiratory problems.  An animals that tries to eat them can end up with such severe swelling of the throat that the airways become blocked entirely, leaving the animal unable to breath and die by asphyxiation.

Th reaction from touching a Processionary Caterpillar starts like a prickly heat and will more often than not require medical attention.  There are many ideas about the best way to get rid of these creatures, one being to burn them.  This is perhaps not such a good idea as in theory the fire could create clouds or airborne poisonous hairs everywhere.  If you find these caterpillars, the best thing is to is keep away from them and they are in you home or garden, call in professionals to get rid of them.  If you live in an urbanisation, you should inform the community, so that they can get them dealt with, and if you suffer a reaction from coming into contact with Processionary Caterpillars you should seek medical help immediately.