How to avoid or prevent processionary caterpillas?

[Jool]

Does anyone know the answer?.

We live surrounded by properties with pine trees and there are loads of nests this year. We have cats and dogs and know that just the hairs of this caterpillar can kill them in less than one hour. We know all about how to destroy the nests etc (which is not always possible as most trees are not on our land...) but isn´t there an insecticide or something you can spray on the trees to stop the moths laying their eggs their in the first place?

Please help.

[El Cid]

Yes, there are insecticides that will kill them but if you cannot reach the nests it is unlikely that you will be able to spray them.

The caterpillars come down at night and form the long columns - I have seen one 3 metres long. They tend to go back to their nests in the early morning.

When we had your problem in a previous house we just kept the cats inside until about 10am and only let them out after we had checked the drive and terraces to make sure that they were not around.

Cats seem to be less likely to suffer from them - I guess they are more naturally cautious than dogs. If an amimal picks one up in its mouth the tongue will swell and cause it to choke. Urgent action is required from a vet if you are unlucky enough to have this happen.

There is a lot of info here:-

http://web.cortland.edu/fitzgerald/Pine ... onary.html

http://www.ibiblio.org/eldritch/jhf/cater.html

Sid

[Don]

We were out in the Doñana forest yesterday and saw masses of the blighters, all in the younger smaller pine trees. Last year we were talking to the guy who looks after the Botanic gardens in Gib (and he also looks after Kew gardens) and he showed us the pheromone traps they put up to attract the moths. I dont know where one would look to get some of these traps to deal with infestation around your home but in principle it should be possible. Apparently if you have an infestation on your land you can call on the environmental Guardia Civil (Protección de la Naturaleza) who will come and deal with them.

Thanks for the links Sid, most interesting.

[Chalky]

Yes, there are insecticides that will kill them but if you cannot reach the nests it is unlikely that you will be able to spray them.

Do you know the names/availability of any insecticides? I know the recommendation is to cut down any nests you can, dowse them with petrol and burn them, but that's easier said than done, especially if you're out in the campo and away from home, so I would like to be able to take some insecticide spray on the off-chance that I can reach the odd nest.

[El Cid]

Any insecticide designed to eradicate caterpillars will do. It should be a pyrethroid type and a commonly available example is DECIS from Bayer. This is fairly easy to find in most viveros. The active ingredient is Deltametrina.

Compo also make an insecticide specifically sold for this problem. It is (unsurprisingly) called Insecticida Procesionaria del Pino. You may find it difficult to find but, personally, I think it is no more effective than Decis.

If you would prefer an ecologically friendly approach you can buy a bacteria that causes the caterpillars to swell and die without any adverse effects on any other insects or plants. That is called Bacillus Thuringiensis and again is easily available. It comes as a powder which can be sprayed when mixed with water.

Sid

[Chalky]

Great! Thanks, Sid

[Wicksey]

We had masses of the things when living in France and the caterpillars were around all day long. We couldn't go near them without coming out in a dreadful rash and the cat was always sick for hours after sniffing them (we did try to keep her away but there were so many of them we didn't always spot them first). We had read that even the nests are dangerous and shouldn't be burnt. We resorted to spraying the caterpillars with hairspray (extra hold!) to stop them expelling their hair and eventually scooping them up on a spade and chucking them into the local ditch which was always running with water. There are a few pine trees with nests here but I think far enough away not to bother us. We said we'd never have pine trees in the garden again as they were such a pest.

[Chalky]

I've seen the use of hairspray recommended elsewhere.

[Don]

Reading up on these things it warns that simply burning them can send the micro fibres up in to the air and spread them (and their nasty effects) around. Bleach is recommended to spray the nests and kill the caterpillars whilst hairspray should help in the first instance to stop the hairs/fibres from being released so easily. One way could be to spray a nest with hairspray to trap in the fibres and cut off the nest into a bucket of bleach and water. Sounds like you have to deal with these things a bit like asbestos in sense of avoiding any dust/hair/fibre release into the air and use pesticide or chemical if you want to kill off the caterpillars.

[Jool]

Thank you everyone for your replies. I love trees but have even considered chopping the trees down inside our garden as it is such a worry....I don´t think you are supposed to chop pine trees down though....

Jool