Pine processionary caterpillars and dogs: spring's hidden danger
The pine processionary caterpillar is one of the most serious dangers to dogs in Greece. How to recognize it, what to do after contact, and how to avoid it.
7/9/2026
· Gatsou Team
· safety, health
Few dangers to dogs are as insidious as the pine processionary caterpillar. A few seconds of curiosity — one sniff or one lick — can end in tongue necrosis and emergency surgery. Every dog guardian in Greece should know what it is, when it's around, and what to do after contact.
What is the pine processionary?
It's the caterpillar of the pine processionary moth, a nocturnal insect that nests in pine trees. The caterpillars move along the ground in a distinctive "procession" — one behind the other, like a little train — and are covered in thousands of microscopic toxic hairs. Those hairs cause severe inflammation and tissue necrosis in whatever they touch: tongue, lips, nose, eyes.
When and where will you encounter it?
Mainly from late winter through spring — that's when the caterpillars descend from their nests to bury themselves in the soil. The nests are easy to spot: they look like white silk "bags" hanging from pine branches. Watch out in parks, pine woods, yards and streets lined with pines — which is to say, almost everywhere in Greece.
What are the symptoms of contact?
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Sudden, intense drooling — the most common first sign
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Rapid swelling of the tongue, lips or muzzle
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Frantic licking, pawing at the mouth, whining from pain
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Vomiting or retching
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Difficulty breathing or swallowing — extremely urgent
First aid: what do I do immediately?
1
Don't rub the contact area
Rubbing breaks the toxic hairs and releases more toxin. Don't touch with bare hands — the hairs are toxic to you as well.
2
Rinse with plenty of lukewarm water
Flush the mouth with water flowing outward (not toward the throat), wearing gloves if available. The goal is to wash the hairs away, not have them swallowed.
3
To the vet — immediately, no waiting
Early anti-inflammatory treatment within the first hours makes the difference between full recovery and permanent damage. Call ahead so they're ready for you.
4
Don't wait for it to "pass"
Even if symptoms seem mild at first, necrosis progresses over the following hours. Contact with a processionary caterpillar is always an emergency.
Tongue necrosis from processionary hairs develops within hours — and can end in partial amputation of the tongue. Every minute counts: treat EVERY contact as an emergency and head to the vet immediately.
How do I protect my dog?
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From February through May, keep your dog on a short leash near pine trees
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Check the pines in your yard for nests in winter — the white silk 'bags' are clearly visible
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Learn to recognize the 'procession' on the ground and change route
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For nests in your own trees, call a professional pest controller — never destroy them yourself
It's also worth brushing up on Gatsou's pet first aid guide — in processionary incidents, the right first moves are literally life-saving.
Frequently asked
When do processionary caterpillars appear in Greece?
Mainly from late winter to late spring, usually peaking between February and April when the caterpillars descend from the pines. In warm years they can appear even earlier.
Are processionary caterpillars dangerous to cats or humans?
Yes. The toxic hairs cause serious reactions in cats and humans too — especially in children. Never touch caterpillars or nests with bare hands.
My dog sniffed a caterpillar but seems fine — should I still see a vet?
Yes. Symptoms can develop over the following hours, and early treatment prevents the damage. A precautionary check is infinitely better than necrosis caught too late.
How do I remove processionary nests from my garden?
Don't attempt it yourself — the hairs stay toxic even in old, "empty" nests. Call a professional pest controller, or notify your municipality if the trees are in a public space.
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