Oak processionary


Thaumetopoea processionea

The oak processionary moth is a moth. It belongs to the order of butterflies (lat. Lepidoptera) and there to the subfamily of processionary moths (lat. Thaumetopoeidae). It gets its name from the behavior of its caterpillars, which move in multi-row "processions" on the trees to their feeding places. The caterpillars attack oak species, and their stinging hairs can be dangerous to humans.

The moth is medium-sized with a thick-bodied body. Its proboscis is completely recurved. The wingspan is 25 - 25 millimeters.
The caterpillar is up to 5 cm long and has a dark, broad dorsal line with velvet-like hairy fields and reddish-brown, long-hairy warts (stinging hairs). It is active at night and feeds on the leaves of various oak species.

Life cycle of the oak processionary moth.

The caterpillars of the oak processionary moth live gregariously in gossamer nests on the tree. From there, they move in close lateral contact in a multi-row "procession" to the feeding site. When they occur en masse, they can cause considerable damage.

They are mainly controlled for health/hygiene reasons as their stinging hairs can cause allergic skin and respiratory reactions in humans. The stinging hairs break easily and are carried over long distances by air currents in favorable weather. Caterpillar hairs are long-lived and accumulate in the environment for several years, especially in undergrowth and ground cover.

Damage caused by oak processionary moth

Damage is caused by the caterpillars of the oak processionary moth. This ranges from pitting to balding damage to various oak species. The caterpillars shed stinging hairs that can cause allergic skin and respiratory reactions in humans.

What plants are infested by oak processionary moths?

Various oak species in forests and individual trees along roadsides, in parks and in urban areas.


Control oak processionary moth with nematodes

How does oak processionary moth control with nematodes work?
Nematodes are tiny, thread-like soil organisms about 0.6mm long. Our product Tp-Nema® contains nematodes of the species Steinernema feltiae, which kill the caterpillars of the oak processionary moth and use them for their own feeding and reproduction.

The nematodes are supplied alive in a powder. For application, mix them with water according to application instructions and apply to affected trees.

IMPORTANT: The use of entomopathogenic nematodes is NOT included in the scope of Regulation (EU) No. 528/2012 (Biocides Regulation).

Instructions for use Tp-Nema®.

Which stages of the oak processionary moth can I control?

Application is possible as soon as the caterpillars have hatched, i.e. mid to late April. Control is possible up to and including the 3rd caterpillar stage, which is usually by the end of May. The treatment should be repeated within 2 weeks.


Application period: mid-April to the end of May

Correct use of nematode products against caterpillars of the oak processionary moth

Mix the nematode solution according to the instructions in the application notes and apply directly to the tree crowns using a tree sprayer/spray gun or motorized backpack sprayer.

Due to the risk of desiccation, to ensure low wind conditions, and to directly target the caterpillars, nematodes should be applied in the evening and at night between 8 pm and 6 am.

Further information and advice

Do you have questions?

Feel free to contact us personally.