Love it!

Giive them a bad hair do and they'll be too embarressed to go out.

I seem to remember they are harmless in the first couple of instars.

Personally if they were a problem here, then I would be looking for signs at the start of the season, and either as a precaution or as a necessity, I would spray the tree with pesticide. I know Fiona won't like it, but better that than my dogs getting sick.

If you have no ladder long enough to get up there, get the tallest step ladder you can, fit a long extension plastic flex tube between the spray body and the metal tube, and tie the latter to a very long bamboo, or two bamboos tied together. Pump like crazy, and you ought to be able to get it up and all over the top of the tree.

Bil, thanks for that. As always a fund of practical genius!

I tried spraying the trees and the nests repeatedly much as you describe,but only had limited success,so after a few years with the nests progressively getting higher and further out of reach each time, I resorted to the ultimate solution,as per my first post.

Possibly a stupid question, but have you tried confidor? Only it's a systemic, and should get the ones you can't reach.

Its a while since now but I think I tried everything I had incl.confidor.
Not sure if pine needles absorb chemicals the same as other plants and bearing in mind the massive height and depth of some pine trees, its difficult to get decent coverage as well as reach them,unless I hire a helicopter or something.
Another thing about the pines,..I killed some big ones off quite easily by drilling into the core and putting a drop round-up into them,...yet a few weeks ago I sprayed some very tiny ones with round-up,but up to date, absolutely no sign of any effect on them,....so not sure if the needles take the stuff up the same as leaves.
The only thing which had much effect when I sprayed the big ones was aguafuerte,though its dodgy stuff to be spraying about at great heights.
It had the effect of burning into the nest and scorching their backsides a bit but didn't completely finish them off, as they were just too high and far in to get good coverage,...also turned much of the tree a sickly shade of white....

Hmmm. a truly nasty problem. Are there pheromone traps available?

I think they've only had limited success and are not really practical to cover a large area.
One thing I did try a few years ago was that sticky gluey stuff thats used to catch mice.
I put a big band of it about a meter up a couple of great big pines with nests way up high,ensuring there was no other path from the tree.
I checked them regularly, but not one single caterpillar did I catch so where they went is a mystery to me,..... unless they comitted hari-kari by diving of the top branch.
However I have heard it said that they can pupate under the bark of the tree on occasions,........in any event they were back up there as usual the following years.

Hi, we put a couple up last year and caught literally hundreds of male butterflies and we thought, yippeee, so many nests less next season. I can assure you there were just as many, if not more, so the surviving males must have been busy.
So these pheromone traps aren't worth investing in...

It is a rather difficult problem. As with all things, it can be very difficult to see how well it works. It's a great shame that the traps don't get females, as it only needs a few males to father a large caterpillar infestation.

With such a hard to destroy pest it pays to hit them at every stage of their lifecycle.

The tragic death of the trees themselves is obviously a solution, but if that is impossible, then there are a few lines of attack that ought to help. As with the pheromone traps, just because it doesn't solve the problem in one hit, doesn't mean it is useless.

One useful question is, how fast does this pest spread? I have seen info that the female lays her eggs straight away. If this is so, and she does not fly off to infest other trees, then the advance might be slow. If this is the case, then it might be feasible to have a campaign that could be effective.

First, it would pay to make it more accessible to spray the tree either by creating ladder access to the top, by removing a branch or two, so that one could spray all parts of the tree, especially at night when the young larvae are feeding. A high pressure water jet with slightly soapy water might be useful (only in the early instars before they are toxic) in breaking up the nests and rendering the caterpillars more exposed to a pesticide spray the following day/night.

Pheromone traps get some, and then it might be interesting to have a fairly vigorous campaign against the caterpillars which descend to pupate. Do any remain in the trees, do they drop, or do they climb?

A multiple pronged attack like this might show good results, but require a huge investment in time and energy which some people can't provide.

Also its success would depend on a very slow rate of incoming moths from surrounding areas, and it would have to be repeated every year without fail.

You can really understand why someone would want the trees cut down, can't you?

There are some chemical treatments other than spraying.

Just as palms can be treated against the palm beetle by injecting insecticide into the trunk, so can pine trees. If done early enough it will kill all of the caterpillars.

There is another interesting treatment which involves shooting insecticide pellets into the nest with an airgun!

http://www.martinezpascual.grupouni2.com/baleng.htm

Interesting ideas,but practical solutions I'm not sure.
The airgun idea seems to be fairly recent idea,maybe not fully proven, from someone with a commercial interest,and appears to have its risks, even if it is as effective as claimed.
Interested what chemical injection you refer to Fred,..though I can guarantee that a round-up injection is very effective permanent solution,if not a pretty sight.
Ladders into the top of the tree,..certainly not for me.
Some of these pines can be a hell of a height and likely out of reach of ladders, on many occasions,...then they are so thick and broad,..probably like a jungle up there,...may work for some but I doubt it for the really big ones,without a professional tree-surgeon/lumberjack.
High-pressure hose may be a possible option, but the stuff could end up anywhere.
Another thing I tried was a fairly powerful kids watergun/rifle with a good capacity,...but just with limited success and no good on the highest,thickest trees.
For those who do reach and cut down the nest-bearing branches, its best to spray them with something first,then spray them again on the ground possibly with aguafuerte to stop the hairs getting airbourne before further dealing with and disposing of the nests.

We've got two huge pine trees in our back garden and it's lovely to see them completely and totally caterpillar free but then I am back in England

The article I read suggests "Orthene" but the other stuff that works well on the palms is "Confidor" which is readily available in Spain - I use it a lot on Citrus as it is a systemic insecticide and is absorbed into the tree and remains active for some time.