Pine processionary caterpillar in Spain: Dangers and advice

Last updated on April 23rd, 2020 at 12:25 pm.

If you live in Spain or visit during the springtime, you might have heard people talking about the pine processionary caterpillar. 

This specie is often mentioned by dog owners who are warning others of the danger. They’re a real threat too; we don’t usually associate caterpillars with the potential to kill, but this species has caused the death of many dogs and other animals. Pine processionary caterpillars have even made their presence felt amongst dog owners themselves, causing itchy and painful rashes, or at worst, fatal anaphylactic shock.

What is the processionary caterpillar?

The pine processionary moth hatches around May to July and only lives for about a day. During this time it must mate and lay its eggs in the foliage of a pine tree; a single female can lay up to 300 tiny eggs and it takes around a month for them to hatch. Once hatched, the caterpillars have five growth stages called ‘instars’. During their third instar, they build a white cotton wool-like nest and continue to feed on the pine leaves until the fifth instar. This usually happens any time between February to April.

At this point, the caterpillars, or procesionaria del pino, make their way to the ground in a long chain, or ‘procession’, searching for the next place to continue their life cycle. This behaviour gives them their name. You can recognise them by their distinctive orange and brown colour and blue bands. Eventually, the caterpillars will disperse to burrow just below the ground where they will pupate. Before this happens they can be a danger to humans and other mammals. It is their hair that is dangerous; if they are poked or touched they cause a nasty rash and give off particles that can cause respiratory problems. They are particularly toxic for children and animals.

If the caterpillar is stressed or threatened it can eject its hairs, which act a little like harpoons that penetrate and irritate any exposed skin. Dogs are particularly vulnerable as they will pick up the hairs on their paws and lick them as they start to itch. This transfers the hairs on to the animal’s tongue, resulting in itching, swelling, vomiting and even death.

What you should do if you find them

If you find the processionary caterpillar within your community:

• You should immediately inform fellow homeowners and organise their removal. In some areas, the council will have a removal service, but where this isn’t the case, you should contact a specialist. Remember, you should never attempt to remove the caterpillars yourself as they pose a serious health risk.
• If you do touch one and feel itchy, you should consult a doctor – rashes can be very irritating and can last for a few weeks.
• You should also be careful of any nests the caterpillars have left in the trees. These will also contain hairs that the larvae have left behind. You shouldn’t try to cut down the nests or burn them yourself, because the hairs can become airborne. If inhaled, the hairs of the pine processionary caterpillar can cause respiratory difficulties or a serious allergic reaction.

What should you do if your pet comes into contact with the processionary caterpillar

If your pet comes into contact with the processionary caterpillar, small white spots will appear around their mouth and on the tongue. As the rash develops, the animal will become distressed and possibly drool. If untreated, animals can die as the tongue will swell. If you think your pet has been affected then you should visit a vet immediately. They’ll likely administer a cortisone injection to counteract the reaction.  

More information

Processionary caterpillars are a real pest. Not only are they are a threat to humans and animals, but they’re also a threat to the pine trees themselves. If you find evidence of the processionary caterpillar in your area, contact the authorities or a removal expert immediately. Furthermore, if there’s someone new to your community, alert them as to the risk – especially if they’re a dog owner.

And remember that if you have any questions or you would like more information about Spain, its legal system or the procedures for buying a house here, you can call us or fill out this form and we will get back to you as soon as possible.