[Helena Wiesner]

For the first time this year, we found a cotton-wool ball of processionary moths on our fairly young umbrella pine in southern Greece. We cut it out and destroyed it but fear that they'll return (there seem to be more and more of them in Greece now). Any advice, particularly given that we're not there to watch over the tree the whole time?

Helena

[Fleur Pavlidis]

Don’t panic and avoid Google. I was amused by you calling these pests processionary moths – I imagined them flying in ranked procession – when in fact it’s the caterpillars which travel nose to tail. Although they can be damaging to young trees, deadly infestations are not very common and probably depend on specific conditions of climate etc which happen in one year but not the next ten or so. When we lived among the pines in Agia Paraskevi the number of nests was very variable but never serious for the big trees. I had  a nest on a young stone pine here  last year which I just left and there was no repeat this year.

[MikeHardman]

Donkeys years ago, it may have been in the Guinness Book of Records for 1966, somebody described a bit of a cruel experiment with processionary moth caterpillars. They diverted a procession onto the rim of a bucket, and when the leader completed the loop and hit the followers, the procession was broken - so there was a circular procession on the bucket rim.  As I recall, it kept going for a few days before they all died.

Do be careful of the caterpillars' hairs - they are irritant and allergen.