The appearance of processionary caterpillars

THE processionary caterpillars are known for their gregarious behavior and negative impacts on trees as well as the health risks they represent for humans and animals. Correctly identifying these caterpillars can help take the necessary steps to control their presence and reduce their unwanted effects. This detailed guide provides you with specific information on what these pests look like.

The general appearance of processionary caterpillars

Processionary caterpillars get their name from their habit of moving in long lines, like a procession. In the larval stage, these caterpillars can measure 3 to 4 centimeters long. They are distinguished by their bodies covered in stinging hairs. These hairs are a defense against predators, but they are also a source of irritation and allergies for humans and pets.

Distinctive features

THE pine processionary caterpillars are particularly recognizable by their grayish hairs and darker longitudinal lines along the body. The head is black and contrasts with the rest of the body. It is essential to never touch these caterpillars directly due to their stinging hairs which shed easily and can be blown away by the wind.

As they progress, caterpillars develop more pronounced and visible segments, making them easily identifiable when moving in groups. The procession phenomenon is very characteristic: young caterpillars instinctively follow the lead caterpillar, forming a long chain which can sometimes reach several meters.

Visual detections and precautions

Observing the nests of processionary caterpillars is another way to identify them. In autumn and winter, they build silky, whitish nests in the branches of pines and other conifers. These nests can be large and are often multiple. From the nest, they can move en masse in search of food, making them all the more recognizable.

It is advisable to avoid any direct interaction with these nests or with the caterpillars themselves. Their hair can cause severe allergic reactions, including itching, skin and eye irritation, and even difficulty breathing. If present in a busy space, it is preferable to call on professionals for appropriate treatment.

Environmental impact and management measures

THE processionary caterpillars are not only a health risk but also a danger to trees. By feeding on pine needles, they considerably weaken trees and reduce their ability to regenerate. Quickly identifying these pests and taking appropriate action can help protect green and forest spaces as well as local biodiversity.

Managing processionary caterpillar populations often involves the use of biological control methods, such as the introduction of natural predators or the use of pheromone traps. These methods make it possible to control the caterpillar population without harming the ecosystem. Planning early interventions is crucial to minimize their negative impact.