Monday, 8 December 2008

Processionary Caterpillars

A couple of weeks ago and today we were busy with processionary caterpillars. Destroying their nests that is.

We had seen the nests in one of our trees and thought it was from a spider or something similar. But some kindly people told us they were chenilles de procession or chenilles processionaires - in English, Processionary Caterpillars.

After doing some research on the critters we decided to get rid of them as they can be a danger to both human and animals.

Being new-comers to the village we did not want to be the ones who were responsible for aiding their survival. But we are a little surprised at some reactions that people didn't seem too concerned - I guess it depends on whether you are used to knowing about them, how dangerous you think they are, if you have pets yourself, etc.

Some caterpillar facts:

  • up to 300 per nest
  • they come out at night to feed
  • during the day they are wrapped up safely in a cocoon nest
  • the sun helps them to digest their previous night's feast
  • they 'march' in procession (also called Indian file) nose to tail, following a pheramone scent
  • they march during January-March, when they are ready, sometimes several hundred long
  • they die at below -16 degrees (however, in their nest it can be several degrees warmer than the outside temperature)
  • +60 degrees is sufficient to 'neutralise' the poison from their hairs
  • they are poisonous at all stages of their life cycle
  • physical contact can cause oedema, asthma and other respitory problems in those prone, skin rashes, swelling of the tongue, and more
  • found around the Mediterranean
Our plan of attack was to spray the nests then cut off the offending branches and burn them. We were told to wear protective clothing, just in case, as if they feel threatened, they can eject an urticating poison from their hairs.

After buying some poison we then decided not to spray as it is the wrong time of year to catch them with the spray (which we didn't know until we read the packet), some of the nests were way out of reach and we weren't sure how the caterpillars would react - some might escape the nest etc. So just went with part two - burning.

So Wouter dressed up in some old clothes, protective mask, gloves and an old MacIntosh raincoat he got from the Faversham local store for 10/6- (ten shillings and sixpence) in 1967. We got the fire going and Wouter dropped the trees one at a time, then cut off any branches with nests and put them on the fire. The first lot we did were small (trees and nests) by comparison to today's lot - but of course there were a couple of weeks in between and the little critters had lots of time to grow bigger. During the first fire we saw no visible movement from the nests as they were destroyed, but the ones we did today there were very large caterpillars once the protective web had burnt away. The caterpillars were falling over each other and dropping out into the fire - a bit like when you pick up a lot of worms together - all wound around each other.

The following websites have a lot of information and now we know what they are, what they do and when they move about, we can be on the lookout at the appropriate times and keep ourselves and the dog safe.

http://planetepassion.com/Pine_processionary_moth_thaumetopoea_pityocampa.htm
http://www.lost-in-france.com/living-in-france/pets/805-processionary-caterpillars

Some pictures of the events:

nests in the large tree -

the little critters feeding at night -
one of the small trees -
one branch with not much left after being eaten -
Wouter stoking up the fire -
Burning begins -
Wouter sporting his trendy MacIntosh -
The large tree today and some of the nests (we lost count but figure there were about 50 nests) -
Caterpillars burning and falling into the fire after wriggling around each other -

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