Danger from stinging hairs from oak processionary moths

The oak processionary moth has poisonous stinging hairs during its larval stages, which can cause damage to human health and symptoms such as caterpillar dermatitis and skin rashes. In addition, the oak processionary moth is also considered a plant pest, as its caterpillars cause damage to the infested oaks by eating, clearing and clearing.

The period at risk from the oak processionary moth extends practically over the entire year, as its stinging hairs not only accumulate in the vicinity of formerly infested oaks (undergrowth, floor areas), but old web nests develop their harmful effects even after months and years and spread through air drifts can.

Health risks from oak processionary moths

The poisonous hair (stinging hair) of the oak processionary moth is a significant health hazard for humans. Oak processionary caterpillars are hairy from the first larval stage to protect them from birds and other enemies. The microscopically fine, inside hollow, approx. 3 millimetre long stinging hairs are continuously secreted, break easily, and drift into the wider spatial environment by the wind. Immediately after the second moult, stinging hairs with minimal barbs form from the third stage of development.

Suppose stinging hairs, nests or cocoon remains of the oak processionary moth come into contact with humans’ skin and mucous membranes. In that case, the protein poison thaumetopein unfolds its biochemical irritant effect and can cause caterpillar dermatitis, rash, allergic reactions, inflammation of the conjunctiva, throat, upper respiratory tract, and other diseases cause.

Ecological damage from oak processionary moths

The ecological damage caused by the oak processionary moth is caused by the caterpillars eating clearing and clearing. Even if oaks are eaten entirely bare, the extent of damage is usually relatively low due to the trees’ high regenerative capacity.

However, if an infestation and extensive leaf damage repeatedly occur by oak processionary caterpillars, the affected oaks can be weakened over the long term. This makes the trees more susceptible to other weakening factors such as pests (oak moth, oak powdery mildew, oak gall wasps) and other stress factors such as injuries or air pollution. This not only leads to a loss of tree growth but sometimes even to the death of the oak.

Oak processionary mothEndangerment period of the oak processionary moth

The duration of the threat from the oak processionary moth extends over the entire year. However, there are periods of increased risk, primarily between late May and September. After the egg clutch wakes up with the onset of leaf growth and the caterpillar’s hatch, the oak processionary moth begins to develop its poisonous stinging hairs from around the end of May/beginning of June.

The oak processional caterpillars pupate in their web nests between the end of June and the beginning of July and finally begin their short life of a few days as harmless butterflies at the end of July / beginning of August.

The treacherous: The nests that remain on the oak tree remain risky all year round, as the stinging hairs/cocoon residues they contain are carried by the wind into the wider area and accumulate near the trees’ ground and thus pose a latent danger to passers-by and pets.

Find out how AAA Termites and Pest Control can professionally support you in removing the oak processional caterpillars. »