Processionary Caterpillars in Occitanie: What You Need To Know

In the sunny landscapes of Occitanie and throughout the southern half of France, residents are becoming increasingly familiar with the pine processionary caterpillar. This processionary caterpillar is not just a nuisance; it is a major pest capable of causing a severe infestation in local pine forests.

As the climate warms, these processionaries continue to spread, making it vital for property owners to understand the life cycle of the pine processionary moth (Thaumetopoea pityocampa) and the risks it poses to humans and animals.

Understanding the Life Cycle: From Moth to Larva

The life of this insect begins in summer when adult moths emerge to mate. Though the moth typically lives for only one night, the females manage to lay their eggs in cylindrical masses near the tops of trees. Towards the end of summer, the larvae hatch and the young caterpillars also begin to feed on pine needles. These voracious feeders can cause significant defoliation, which weakens the host pine tree.

As the weather cools, the caterpillar colonies build a silken winter nest high in the branches of a conifer or pine tree. This nest provides a warm environment that is several degrees higher than the outside air, allowing the caterpillar to survive the cold.

The Danger: Urticating Hairs and Health Risks

The primary concern for people and animals is the urticating hairs that the caterpillar develops during its later stages of growth. These hairs contain an irritant protein called thaumetopoein. Direct contact with the insect—or even airborne hairs—can cause a painful rash, severe skin irritations, and allergic reactions, including anaphylactic shock.

Dogs and cats are at particularly high risk because they may sniff or try to eat the caterpillars. Direct contact or contact with a caterpillar can lead to necrosis of the tongue or severe respiratory distress in pets, requiring immediate veterinary attention. Unlike the oak processionary, which stays in broad-leaved trees, the pine processionary frequently comes into contact with residents when they leave their nest to seek a place to bury themselves.

Spring Processions: Leaving the Nest

Between winter and spring, typically from February and March through May, the colonies leave the nest to go down to the ground. They form a long, nose-to-tail procession in a single file line to find a place to bury and begin the pupal stage. During this time, they crawl down tree trunks and across gardens, significantly increasing the chance of contact with a caterpillar. Once underground, they form a cocoon or chrysalis before they eventually emerge from the ground as moths.

How Gecko Pest Control Can Help

Gecko Pest Control provides professional insecticide treatments tailored to the specific tree species and trees affected on your property. Our methods are designed to protect your family while respecting environmental food and forestry policies.

• Nest Removal: We offer mechanical nest removal before the end of February, effectively capturing the colony before they can infest the ground level.

• Biocide Spray: In late summer or early fall, we can use a natural insecticide such as Bacillus thuringiensis. This spray is highly effective against young larvae as they begin to feed.

• Advanced Monitoring: We utilize pheromone traps that use a sexual pheromone to attract and capture male moths, reducing the overall population.

• Physical Protection: We can install a physical barrier or "ecological trap" on the trunk to catch caterpillars as they descend.

If you have a host tree such as a pine or cedar on your property, don't wait for a dangerous irritation to occur. Contact Gecko Pest today to secure your home.