The processionary caterpillar (Thaumetopoea pityocampa) is a common pest among species such as pine, cedar or fir. It is an insect about four centimeters long, with a dark head and stinging hairs that pose a potential risk to pets. They receive this name because at the beginning of spring they begin to descend from the crowns of the conifers, one close to the other. The processionary, however, has a much longer, although less visible, life process that begins in the winter and can cause defoliation in the pines and encourage the appearance of other pests.
The larvae form a kind of silk balls on the branches of pine trees in which they protect themselves from the cold and hibernate. They progressively leave these nests to feed on the needles, which forms dry bouquets and slows the growth of the trees. If the attacks are very voracious, they can even kill the specimen.
Between the months of February and April approximately, the caterpillars descend to the ground, where towards the month of May their metamorphosis occurs. The processionary then turns into a cocoon, from which a nocturnal moth is born, which will reproduce and leave its eggs again in the tops of the pines. Once they hatch, new larvae and caterpillars will emerge to start a new life cycle.
Although there are solutions such as telescopic poles to eliminate nests or chemical treatments to kill the youngest caterpillars, the most ecological way to eradicate the processionary is through biological control. In fact, there is a bacteria sold in garden stores called Bacillus thuringiensis that attacks the digestive system of these insects and deprives them of food. You can mix it with water and, with the help of a sprayer, periodically spray the silk nests, which can be an inconvenience if they are at a certain height.
An alternative that will help you prevent the appearance of the processionary in your garden is to ally yourself with its natural predators: birds. You can buy them at a pet store, or install huts and feeders to attract species such as titmice, titmice or hoopoes, which in summer dig through the leaves to devour the chrysalises. In this way, you will be able to cut the reproductive cycle of the processionaries and guarantee a safe environment for your children and pets.
