Last week we spotted bunches of webbed nests in the pine nut trees, and immediately went on alert as we knew they were harbouring the larvae of the Pine Processionary Moth. The larvae overwinter in these nests, leaving at night to forage on the needles. If there are enough caterpillars they can easily defoliate a tree, and consequently are considered a major economic pest in southern Europe.
Apparently the nest has no openings, so caterpillars force themselves through the layers of the shelter and their waste (frass) is that mess accumulating at the bottom of the nest. However their feeding behaviour is not what worries us, it is their hairs.
The hairs can cause anything from mild skin inflammation to a major allergic reaction, and you might not even realise you have had contact until it is too late as the hairs easily drop off on the ground as they move. And they move lots, and not just in the trees. From this time of year until early spring long processions of them, sometimes up to three hundred individuals, travel on the ground. They are heading for soft ground to bury themselves for the pupal stage of their development. Click here for a previous post when I videoed a procession of around fifty. It is quite extraordinary.
My tip of the season – don’t let your pets or children near the caterpillars, don’t camp under pine trees and don’t walk barefoot near pine trees in southern Europe either!