# Pine processionary moth (Thaumetopoea pityocampa) > A Mediterranean pine-feeding moth whose communal, urticating caterpillars form striking head-to-tail 'processions' and can cause health and forestry problems. Source: https://insectscanner.com/species/pine-processionary-moth/ (updated 2026-10-10) ## Is it dangerous? **Urticating hairs.** Caterpillars carry barbed urticating hairs that cause skin irritation, itchy rashes, and eye inflammation (conjunctivitis); hairs can also become airborne from nests. Avoid touching larvae, nests or hairs. If exposed, remove hairs with adhesive tape, wash skin with soap and water, rinse eyes with plenty of water without rubbing, and seek medical care for eye exposure or severe reactions. If someone has signs of a severe allergic reaction (trouble breathing, swelling of the face or throat, dizziness), use their epinephrine auto-injector if they have one and call emergency services. **Pets:** Very dangerous to pets. Dogs and cats investigating or licking caterpillars can suffer severe tongue and throat swelling, drooling, vomiting, tissue death on the tongue and in some cases life-threatening reactions. Rinse the mouth gently with water without rubbing, and seek veterinary care immediately if a pet contacts or ingests caterpillars. ## Quick facts - Scientific name: Thaumetopoea pityocampa - Also called: Pine processionary - Order: Lepidoptera (Butterflies and moths) - Family: Notodontidae (Prominent moths) - Size: 30-40 mm wingspan - Colours: Sandy brown, Dark brown, Grey, White (silk nests/hairs) - Habitat: Pine forests and plantations, mixed woodlands with pines, and nearby urban parks and gardens where host pines grow - Range: Native to the Mediterranean region: southern Europe, North Africa and parts of the Middle East; expanding northward into central Europe with climate change - Active: Adults fly in summer (often July-August); larvae feed and are active through autumn and winter; processions and pupation occur in late winter to spring - Lifespan: Adults live a few days to about 1 week; full generation from egg to adult typically one year - Effect on plants: Defoliator - Pest: yes ## Overview Thaumetopoea pityocampa is a moth species best known for its social larvae that build silk tents in pine trees and move in nose-to-tail processions when leaving the nest to pupate. The caterpillars feed mainly on pine needles and can heavily defoliate trees, causing growth loss and increasing tree susceptibility to other stresses. The larvae carry microscopic urticating hairs that cause painful skin rashes, eye inflammation and allergic reactions in humans and animals. Adults are short-lived moths that mate and lay eggs in summer; larvae develop through autumn and winter and pupate in spring. ## How to identify it Adult moths have grey forewings with darker transverse bands and white hindwings; wingspan typically about 30-40 mm. Males are usually slightly smaller and more slender than females. Caterpillars are densely hairy, grey-black with tufts of orange-brown hairs along the back; from the third instar each larva bears many microscopic, barbed urticating hairs that detach easily. Larvae live in conspicuous white silk tents in pine branches. - Look for white silk tents (nests) in pine branches during autumn and winter. - Observe the characteristic nose-to-tail processions when larvae leave the nest to pupate. - Note densely hairy, grey-black caterpillars with orange-brown hair tufts on the back. - Adults are grey moths with darker transverse bands, white hindwings and a 30-40 mm wingspan. ## Lookalikes - **Oak processionary moth** (Thaumetopoea processionea): Oak processionary lives on oaks (not pines) and the caterpillars have different banding and nest placement; both have urticating hairs but host tree and timing differ. - **Other processionary moths** (Various Thaumetopoea spp.): Other Thaumetopoea species may look similar as adults or larvae; check host tree (pine species), locality and nest/behaviour to separate species. ## Life cycle - **Egg:** Females lay eggs in cylindrical masses wrapped around pairs of pine needles in summer, covered with protective scales; eggs hatch after about a month. - **Larva (caterpillar):** Larvae feed communally on pine needles through autumn and winter, build silk tents and go through several instars; they produce urticating hairs. - **Pupa (cocoon):** Fully grown larvae leave the tree in procession to pupate in the soil in late winter or spring inside earthen cocoons. - **Adult (moth):** Short-lived moths emerge in summer to mate and start the next generation; adults do not feed significantly. ## Diet and predators - Young eat: Pine needles and occasionally needles of other conifers such as cedar - Adults eat: Adults feed little or not at all; they live to mate and lay eggs - Predators of the young: Birds, some parasitic wasps and flies, and small mammals (but many predators avoid hairy larvae); pathogens and fungi can also kill larvae - Predators of adults: Bats, nocturnal insectivorous birds, and predators/parasitoids of moths ## Effect on plants and gardens Larvae feed primarily on needles of pines (Pinus species), and occasionally cedars and other conifers; heavy or repeated defoliation reduces growth and can kill weakened trees. ### How to get rid of it Combine prevention and targeted control: monitor for winter nests and remove/destroy nests professionally (use protective gear or hire specialists). Use pheromone traps to monitor adult flights. Biological control includes Bacillus thuringiensis kurstaki (Btk) sprayed on needles to kill young larvae, and release or encouragement of natural enemies (parasitic wasps, birds). Avoid indiscriminate insecticide spraying; treat nests in late winter/early spring when caterpillars are accessible and before dispersal. For public areas, close-off zones and place warning signs to prevent human/pet contact. ## Where and when to find it Look high in pine canopies for white silk tents in autumn-winter; processions may be observed on trunks or on the ground when larvae descend; adults are attracted to light in summer. - Best time: Best months to see larval nests and processions are October to April depending on local climate; adult flight is usually July-August. - Tips: Do not approach nests or caterpillars without protective clothing and gloves because hairs can become airborne; use a telephoto lens to photograph nests from a safe distance and note the host pine species. ## Fun facts - Larvae move in single-file processions led by a leader caterpillar — a behaviour used to locate pupation sites. - The species is expanding northwards in Europe as winters become milder, creating new health and forestry concerns. - Their communal silk tents act as winter refuges and can be very conspicuous in pine canopies. ## Frequently asked questions ### Are pine processionary caterpillars dangerous? Yes. Their tiny barbed hairs can cause painful skin rashes, eye inflammation and allergic reactions in people and serious, sometimes life-threatening reactions in pets. ### Do pine processionary moths bite or sting? Adults do not bite or sting. The danger comes from caterpillars' urticating hairs, not a bite or sting. ### Why are these caterpillars on my pine tree? Larvae feed on pine needles and build communal silk nests in the tree for shelter during cold months; if you have pines they are a suitable host. ### How can I get rid of pine processionary caterpillars safely? Do not handle nests or caterpillars without protection. Hire professionals to remove or destroy nests, use targeted Btk sprays against young larvae, and use monitoring traps. Close off public areas and warn pet owners. ### When am I most likely to see them? You will typically see silk tents in autumn and winter and the famous processions when larvae descend to pupate in late winter to spring; adult moths fly in summer. ### Can these moths kill trees? Severe or repeated defoliation by large outbreaks can weaken trees, reduce growth and in combination with other stresses may kill susceptible trees, especially young or already stressed ones. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/61293), [Wikipedia](https://en.wikipedia.org/wiki/Pine_processionary). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.