The processionary caterpillars, these small hairy beasts, represent a real scourge for trees, especially pines, cedars and holm oaks.

They are also a threat to the health of domestic animals and humans.

In fact, its sharp hairs can cause allergic reactions and skin irritations.

Find out how to get rid of these pests using eco-friendly methods.

READ: Allergies in dogs: how to recognize and treat them effectively?

Identify processionary caterpillars and their life cycle.

Processionary caterpillars are the larvae of the moth Thaumetopoea pityocampa.

They are characterized by their gray to brown color and their body covered in sharp hairs. Their name comes from their gregarious behavior: they move in procession, one after the other, in search of food.

The life cycle of processionary caterpillars is divided into several stages:

1. Egg laying by adult moths on tree branches and needles, usually between June and September.
2. The hatching of the eggs and the appearance of the first larvae, approximately 30 days after laying.
3. The growth of larvae in several stages, during which they feed on the needles and leaves of trees.
4. The formation of cocoons and the transformation of caterpillars into pupae, usually between February and April.
5. The metamorphosis of nymphs into adult butterflies, which fly away to reproduce and lay eggs again.

Take preventive measures to prevent their proliferation.

The first step to eliminate processionary caterpillars is to act upstream to prevent their development and proliferation.

Several preventive solutions can be implemented:

• Plant hardy trees: Certain tree species are less likely to be infested by processionary caterpillars, such as Scots pine, black pine, or Aleppo pine.
• Install aviaries: Insectivorous birds, such as chickadees, are natural predators of processionary caterpillars. By installing nest boxes in your trees, you encourage the presence of these allies.
• Give preference to biological control methods: the introduction of natural predators, such as parasitoid wasps or ladybugs, makes it possible to regulate the population of processionary caterpillars without the use of chemicals.

Treating Trees Infested with Processionary Caterpillars

If, despite your prevention efforts, processionary caterpillars have infested your trees, several control methods can be implemented:

1. Caterpillar Entrapment: Specific pheromone traps attract and capture adult moths before they lay their eggs. They will be installed between June and September.
2. Mechanical weeding: This involves manually removing the nests of caterpillars with a telescopic pole or pruner. This operation must be performed carefully to avoid contact with the sharp hairs.
3. Biological treatment: the use of products based on Bacillus thuringiensis, a natural bacterium, allows the caterpillars of the processionary caterpillar to be infected and killed without harming the environment.
4. Mechanical control: Anti-caterpillar collars, also called eco-traps, can be placed around tree trunks to prevent caterpillars from descending and taking refuge in the ground to become nymphs.

Protect yourself and your animals from processionary caterpillars

The stinging hairs of processionary caterpillars can cause allergic reactions and skin irritations in humans and pets.

Therefore, it is critical to protect yourself and your animals during control operations for these pests:

• Wear protective clothing: When weeding or setting traps, consider wearing gloves, goggles, and clothing that covers to avoid contact with sharp hairs.
• Watch out for pets: Dogs and cats are particularly susceptible to the stinging hairs of processionary caterpillars. Be sure to keep them away from infested areas and seek veterinary attention immediately in case of contact.
• Collect dead caterpillars – The stinging hairs of processionary caterpillars remain active even after their death. Remember to pick up dead caterpillars carefully and dispose of them in an airtight bag to avoid any risk of contact.

Getting rid of processionary caterpillars is a difficult task that requires prevention and specific actions. By favouring eco-friendly and environmentally friendly methods, you not only help to protect your trees and health, but also to preserve the biodiversity and natural balance of your garden.

Do not hesitate to go to the professionals if you find yourself facing a major infestation, so that you can benefit from appropriate advice and effective intervention.

Finally, stay alert and informed about the methods of combating and preventing these pests, because the best weapon is knowledge.