Beware: Processionary Caterpillars

I knew nothing about these creatures until we bought our house in France. I can’t remember when we first became aware of their existence, probably after the arrival of Zeph. Neither can I remember exactly when we spotted their nests in two of our large pine trees. I’ve searched through our many photos of the garden, but can’t find any images of the nests.

The pine processionary caterpillar is found in large areas of France, particularly in the south. However, with climate change, they have been appearing further north, as well. The more I find out about them, the more worrying they become, especially as a dog owner.

The caterpillars are dangerous to dogs and humans because they have thousands of microscopic hairs, which can cause severe allergic reactions. In humans, these include major skin irritation and breathing issues, but in dogs, licking the caterpillars can lead to necrosis of the tongue, which can be fatal.

The moths of the processionary caterpillar are unremarkable, small and greyish brown. They are nocturnal, normally only alive for one night. Their eggs are laid in summer, and the nests resemble white silk cocoons. It was when we first noticed these that we began our enquiries into what they might be.

The nests can contain hundreds of caterpillars, which descend to the ground from January to May, depending on the weather. This is when they make their long nose-to-tail processions, as they search for a place in the earth to pupate. Not only are they a threat to people and animals, but the caterpillars feed on pine needles, thereby weakening or compromising the host tree.

There are some natural predators, such as Crested tits, that eat the eggs and young caterpillars. Cuckoos also eat the caterpillars, and Hoopoes the pupa. Bats eat the moths, but this has little overall impact. So, how do you get rid of these unwelcome visitors? There are some traps available for purchase, but the overriding advice is to employ a professional.

As luck would have it, Dan, who looks after the house and garden in our absence, is a qualified tree surgeon with extensive and practical knowledge to sort out our tree-related problems. As we have been advised to have the nests and trees removed before we put our house on the market, this has taken place in our absence.

We are due to return to France shortly, and I will be relieved that this issue has been sorted. The further I have researched into pine processionary caterpillars, the more relieved I am that this threat to Zeph, in particular, has been removed.