These are found throughout the warmer regions of Southern Europe, the Near East and North Africa. In addition to causing widespread damage to pine trees, they are a major danger to small animals (including dogs) and, to a lesser degree to humans. Do not touch them as their very fine hairs are poisonous.
The caterpillars live in silky cocoons in the pine trees, stripping them of their needles. When hungry they will leave their cocoon and move from branch to branch to seek out food. They travel nose to tail in a line, hence the name Processional. They are most prevalent from January to mid April and are at their most dangerous in mid to late February.
If they drop on you or your pet don’t brush them off with your hands as this can cause skin irritation, rash and pain. Dogs, cats and people can also suffer from shock. Hitting them with sticks is not advisable as hairs flying in the air are just as dangerous and the caterpillars are still virulent even when dead.
If your garden or land is home to the caterpillar, the best solution is to burn them but be wary of floating hairs. If the caterpillars are in the cocoon, spray with hair spray, cover the cocoon and the affected part of the branch with a plastic bag, cut down that part of the branch, place it on clear ground and burn it.
If the caterpillars are on the ground, spray them with lighter fuel then set them alight. This reduces the risk of flying hairs. Take particular care with eyes, as infection causes serious pain and swelling comparable to a bad case of conjunctivitis
If you live near pine trees it is recommended that you keep Anti Histamine tablets handy as an early treatment. Dogs are most at risk when sniffing the ground where caterpillars are or have marched.