The South European Pine Processionary Caterpillar

Otherwise known as thaumetopoea pityocampa or Procesionaria del Pino in Spanish, the Pine Processionary Caterpillar is one to look out for if you are ever in the Southern European/North African region in late winter, early spring.

Despite it's cute appearance, this little caterpillar is dangerous to you and extremely dangerous to your pet.


pine processionary caterpillars
pine processionary caterpillars

The body of the processionary caterpillar is covered with fine barbed hairs which they can release at any time, as a defence mechanism when disturbed, and most people suffer an allergic reaction to them that can range from extremely itchy blistered skin to anaphylactic shock.

In almost all cases, medical treatment will be required. The itch is especially itchy and painful and lasts typically for three weeks.

If these hairs get into your eyes it can cause blindness, especially in a child or animal.

It is not unknown for dogs to have their tongues amputated after getting stung elsewhere on their body then licking the affected area.

If the dog survived the attack at all, that is.

a line of processionary caterpillars
a line of processionary caterpillars
typical processionary caterpillar nest in pine tree
typical processionary caterpillar nest in pine tree

These caterpillars normally leave their nests in pine trees to forage for food at night before returning home to sleep during the day, literally stripping their host tree of leaves (needles) and sap. Coming out only at night deprives the birds and wasps of a good feed.

They are called processionary because they form a procession, with the head of one attaching itself to the rear of the one in front to form a long line, or procession.

It is in January/February you see their nests hanging on pine trees like big cotton wool balls and it is up to the local authority to clear these nests, by removing and burning them while the workers wear protective clothing.

It is not advisable to take them down and burn them yourself, because of the danger of airborne hairs which can be fatal if inhaled.

They can be destroyed by cold, but it has to fall below minus 16C to be of effect, and the temperature seldom falls this low.

a [[procession of caterpillars
a [[procession of caterpillars

These caterpillars are rarely seen at this stage until they are ready to leave the nest and turn into pupae, the next stage in their life cycle.

Now they leave the host tree, and go off, in a procession of course, to look for soft sandy soil where they can bury themselves until they are ready to emerge as adult moths in the summer.

It is while looking for their new home that they are at their most dangerous to human and animals.

They can be mistaken for a snake as you can see from this photograph here.

I did hear of one man, a British expat who strangely had not heard of these creatures, who was driving up a mountain road one day when he spotted a procession crossing in front of him. Being a kind-hearted fellow, he didn't want to run them over and so stopped and manually assisted them to the other side of the road. I believe he was nearly a month in hospital!

Me, I'd have stopped only so I could reverse over them again!

the adult moths of the processionary caterpillars
the adult moths of the processionary caterpillars

When they become pupae in their underground hole, they survive on the food they have eaten earlier in their life-cycle, until they emerge in the summer as fully fledged and completely harmless if unspectacular moths that only come out at night.

Then the daddy moth mates with the mummy moth and she goes off into the pine trees to lay her eggs, normally around 300 at a time, and the whole cycle begins again.

Is there a long-term solution for the pine processionary problem?

I personally would start by getting rid of all the pine trees; it's not as if they are useful for anything!

The authorities tend to spray the affected areas with insecticides from helicopters once a year, but this has the undesired effect of killing many other insects that are necessary for a balanced ecology, as well as small birds which feed off the insects.

This approach could best explain why every year here there seems to be an imbalance of nature's creatures. Some years there are thousands of earwigs. Other years it's wasps. Yet other years it's snails or the little wriggly grey things that smell when you stand on them (I don't know what they are). Left to nature, there should be no sudden rise in the populations of any insects or small creatures.

There has been some attempts to control the processionary caterpillars by laying pheromone traps to disrupt the mating season, but at the same time there has been a policy to plant yet more pine trees!

And so the cycle continues...

Comments 10 comments

jayjay40 profile image

jayjay40 6 years ago from Bristol England

I didn't know about these caterpillars thanks for the warning


IzzyM profile image

IzzyM 6 years ago from UK Author

You don't read about them in the tourist books, do you? lol Still forewarned is forearmed, so to speak :)


angie 6 years ago

I did exactly what the British guy did...help them across the road. 10 minutes later my hands were on fire, swelling, and changing colors...I lathered them with some clay I brought with me from the states. It's supposed to release venim. 5 hours later, my hands no longer burn, and they are not continuing to swell, but they are not nearly 100%...Geez! Who would have guessed???


IzzyM profile image

IzzyM 6 years ago from UK Author

Oh you poor soul I have sympathy for you!! And of course you will have read above it takes three weeks for the symptoms to disappear. Hope this doesn't ruin your holiday - assuming you are on holiday?


Angie 6 years ago

Yes, I am on holiday...I need to tell you that after 48 hours, I am basically symptom-free. After I slathered my hands in my clay that I mentioned above, a friend gave me an oil that had some medicinal properties from trees in northern Spain and I continuously rubbed this into my hands. I rubbed hard in an effort to break up the toxins that remained in my hands. At first, I couldn't close my fist, there was still a lot of pain, and there was a lot of discoloration. After a rub this afternoon, the discoloration is gone, there is no more pain, and my hands feel as though nothing happened! ...48 hours is much better than three weeks!!! :)


IzzyM profile image

IzzyM 6 years ago from UK Author

I am delighted you came back to update me because I was really worried about you! I don't know what kind of clay you had, or what your pal in Spain gave you but maybe you should consider marketing it LOL, you'd make a fortune!

Am really happy this story had a nice ending :)


maggs224 profile image

maggs224 6 years ago from Sunny Spain

Hi Izzy, we have trouble with these little blighters too, and in answer to your question, yes we are neighbours you live up the mountain from us.

I read your Relleu blog, it sounds like you have much worse weather than we do, must be down to the altitude as we are only a few kilometres from you. Don’t you just love the Spanish banking system? Nice to meet you neighbour I will be looking in on you again soon.


IzzyM profile image

IzzyM 6 years ago from UK Author

Hi Maggs, glad you could get online. Is your comp fixed yet? You did have problems with it or your connection, didn't you?

Yes it is much colder up here. Villajoyosa, probably like Benidorm has a micro-climate and is much better all year round.

God don't get me started on the thieving banks out here! LOL They don't get any better...

I'm starting a new online magazine for local people and holidaymakers to Relleu. I'll put the details in my blog. Thanks for reading :)


Steven 6 years ago

I live in the North in a place called Peralta, Navarra and you wouldn´t believe how many of them we have here, millions! I just looked them up to see if they were procession caterpillars I´d heard about and now, alas, I know that everywhere in the surrounding areas are now pretty much out of bounds for walking.


IzzyM profile image

IzzyM 6 years ago from UK Author

At least you know what they are and to stay away from them. Soon they will all be buried safely underground while waiting to change into moths, and so you will be able to go walking without meeting up with them. Keep your dogs in until the danger has passed, as their poison can kill small animals.

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