Pine Die-back in Crete, Greece
|Thaumatopoea pityocampa caterpillar|
The first suspect was the Pine Processionary Moth, Thaumatopoea pityocampa due to the high number of nests which were visible. These cause massive defoliation of pine trees.
Closer examination of the trunks showed white, fluffy extrusions which looked similar to Pine Beetle pitch tubes.
The true culprit however was nearby in prodigious numbers: The Giant Pine Scale, Marchalina hellenica.
These produce the white fluff that is packed full of nourishing honeydew.
Meanwhile, at the base of the tree the Pine moth caterpillars were not having it all their own way as they were being trapped in sticky threads that appeared to be emanating from the ground.
My guess (and it is only a guess) is that this is some sort of fungal mycelium.If so, what is it and does it have any connection to either the caterpillars or the scale insects? There is still a lot of investigation to be done on plant/fungi relationships and I wonder if the tree could be ‘calling up’ a fungus as a defence mechanism or if the fungus is attacking an already weakened tree.
The following photos show the threads at different levels of magnification and I welcome feedback from mycologists and entomologists on this fascinating (if destructive) set of interactions.
I originally posted this on Facebook (Naturalsits Group) and LinkedIn (Ecology & Evolutionary Biology). As comments are coming in from both groups as well as Steve Lenton's Facebook Group (Cretan Flora) I have decided to publish it here complete with comments from all sides in order to keep the conversation in one place. SD 27th April 2016.