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Oak processionary moth


by Pippa Greenwood

The caterpillars of the oak processionary moth are a real pest, but I couldn't contemplate killing them.


Oak processionary moth, photo courtesy of forestry.gov.ukThe caterpillars of the oak processionary moth are a real pest, but I couldn't contemplate killing them. I find myself in this situation regularly. So many so-called pests are creatures I'm quite happy to live alongside and I do so without a second thought.

The oak processionary moth is native to central and southern Europe. The caterpillars have toxic hairs which can irritate human skin and eyes. They mainly eat the foliage of oak trees and can cause serious defoliation of oaks in some years.

We recently spent a week in France, and were warned by the people we rented the house from to keep away from the 'pretty' hairy caterpillars. I'm no great fan of caterpillars and neither are the kids, so I just yelled a vague sort of warning out into the depths of the garden. But a couple of days later we spotted them. We'd just driven the car through the gate and had stopped to close it before setting off for the day. Suddenly there were yells of a mixture of horror and fascination from the children. I ran around to the back of the car and there they were: about 500 caterpillars writhing en masse across the drive and in to the adjacent field.

Sadly (and yes, I felt really bad about it) we ran over about five of them with one wheel of the car, then after a minute or two's pause the rear part of the procession dutifully walked around their crushed relatives/friends and carried on their way.

We traced them back to the most amazing 'ball' of caterpillars which gradually unfurled to release those in the procession. When we returned they were still marching across the drive, but where were they going? Beyond the drive was a field, at the far side of which stood a lone oak tree.

We parked the car outside the gate to avoid damaging the last of their number. Nothing would have induced us to harm them.



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Gardeners' World Web User 22/04/2010 at 18:34

Good for you, Pippa. We are too quick to kill things. Clearing out my late father-in-law's shed recently,I came across products to kill almost everything creeping, flying or crawling in the garden, plus every weed known to man. I got rid of all of them - carefully. I don't use anything like that and our garden does very well.

Gardeners' World Web User 24/04/2010 at 08:22

We live in France and these processionary caterpillars (oak and pine varieties) are a real issue for people with children and pets. Inadvertent contact with the caterpillar itself or their nests results in very painful skin irritation and can cause serious breathing difficulties if inhaled. The hairs which contain the chemical responsible are shed several times during the nesting stages and are active for years so don't touch old abandoned nests. The French have no compunction in burning nests off the trees, even spraying with chemicals from helicopters in public access woods and forests. With climate change they are now appearing in Southern England - let's see what the authorities do there. See more details

Gardeners' World Web User 26/04/2010 at 09:21

Good to hear that there are so many of us, past and present, who act similarly! But yes, these can be a serious problem as a pest to plants and as a hazard to humans too.....

Gardeners' World Web User 29/04/2010 at 14:22

My friend had a small dog die last year from these "pretty things". Sorry to say, if I see them I lop off the branch and burn them.

Gardeners' World Web User 22/02/2011 at 16:25

Just seen this blog and I know these caterpilars as I live in Spain - BEWARE! If a dog should sniff one, it is usually fatal or causes immense pain, dogs that try to bite them will bite their own tongues off with the pain, puppies are naturally inquisitive and have to be kept indoors or muzzled when the caterpilars parade. They are blind, and the hairs are triggered by a light sensitive patch, so actual contact is not necessary.

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