Note the 'pom pom' effect on the branches.Here's a close-up of an affected shoot:
The damage appears to be caused by clusters of needles dying and dropping off:
This shot shows that multiple areas of single plants are simultaneously affected:
I was told that the effect can be caused by the European Pine Sawfly, but my research shows that this sawfly damages needles in a completely different way: by eating them down to the branch. So it looks like I'm back to square one on this one.
2 comments:
Fascinating - is each pompom a year's growth, or are the damaged needles within one year's growth? Are all the affected trees in one area of the wood, in which case I would suspect some soil/water environmental effect (and in that case I might also expect other vegetation in the area to show peculiarities as well).
I have seen trees patchily defoliated (but not neatly like yours) in other places but that has been down to acid rain which I would not imagine is a problem in Donegal. Plain rain of course is another matter :-).
Intriguing - watch this space!
And Happy Christmas!
Each gap appears to be a single year's growth...from a previous year. This started on one tree and is spreading outwards to neighbouring trees, so I think it's a pathogen, not environmental. Defoliation is never complete: there are always pompoms left. Wonder if it's fungal (I have a sample with dead needles on it on a slide...I'm waiting to see if there are any spores).
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