Up the valley from Tomich

On Thursday after hunting around the garden at Tomich, as in the previous post, I walked Monty for a couple of hours along the roadways and tracks further up the valley, and concentrated on the tree foliage.
Most of the trees are birch, alder, sycamore, oak, spruce and beech, the last obviously having been planted in the great days of Guisachan House, the famous country house that dominated the whole life of the valley.
Trying the farm track, the wildlife hedge planting had been supplemented by the Sycamore cultivar, Acer pseudoplatanus ‘ ‘, with the undersides of its leaves strongly flushed purple.

Sycamore is the only Acer that gets significantly attacked by the tar spot fungus Rytidissima with the narrow yellow edge around the black fungal infection spots. This can be very helpful in identifying the tree!

Sycamore also gets other fungal diseases such as this powdery mildew on the young leaves of this sucker. I don’t know what sort of fly this is!

If there isn’t any tar-spot for identification then it’s down to the shape of the leaves, and the angle of the “keys” definitely nearer 45o than 180o from each other.

Not all the trees here are much infected with tar spot. This particular tree was a favourite haunt of a large number and wide range of flies moving over the upper-side of the leaves, and I think they must have been hovering up either the sugary honeydew or perhaps the more protein-rich pollen that gets stuck in the honeydew. This is said to be quite a common habit for hoverflies and others. Sycamore is thought to harbor a higher population of aphids than most trees, and the aphids and other sucking insects are the source of the honeydew, so this, together with a sheltered and sunny position, may be why there were so many flies on this particular tree.

The most common hoverfly was Episyrphus balteatus,

but also seen was this Syrphus (I think) species, most likely to be Syrphus vitripennis from its partly dark hind femur – the commonest species is Syrphus ribesii, but the hind femur in this is completely yellow. It should be a Syrphus species, because the yellow moustache bands reach the edges of the tergite plates (the plates on the dorsum of the abdomen), and then sweep forward rather than back, and either there are no black bands on the sternites, or they don't extend across the full width, the sternites being the plates on the underside of the abdomen. However there are also a number of other very similar genera, and they are all very confusingly alike.

There was also this rather odd looking fly, possibly a Tachinid. Oddly enough at one point it had raised its front legs off the leaf surface. In the same picture you can also see one of the many smaller black flies running over the surface of the leaves,

Beech has also been planted along the trackside and I was intrigued to notice that as the leaves were beginning to turn on most trees, this sapling was still holding on to its dead leaves from last winter! Is this a record I wonder?

I heard a pair of buzzards, Buteo buteo, overhead, and managed to catch one “in full cry”.

A little further on, there was another possible Platycheirus, this time on a buttercup flower.

The tiny bell-shaped flowers of common heather or ling, Calluna vulgaris.

A beautiful leaf of the Norway Maple Acer platanoides ‘Crimson King’, a striking tree in the overall view.

Purple beech often seems a muddy coloured leaf close up

But can again be spectacular when seen at a distance in contrast to lighter green trees

Here are some odd discoloured patches found just on a few beech leaves and not seen elsewhere

And then my eureka moment. I have often thought beech leaves to be very subject to tip (terminal) scorch, but as I’ve been examining the leaves closely of late looking for galls and mines, I also had a closer look at the scorch today – and WOW! Everytime I saw a scorched tip, leading into it was a thin channel, always starting from just beside the midrib, often torn completely through the leaf, so the scorch must in fact be a blotch mine!

If so, then this is Orchestes fagi, the very unusual beetle larva that mines its way through leaves, in this case beech leaves and only beech leaves. So I’ve finally tracked this down, and in really significant numbers, older trees in particular seeming to be highly attacked. (Later note - having checked the NBN Gateway, a chap called Murdo McDonald recorded these mines exactly here, and also at Plodda and Abriachan inter alia, in 2010!) All the larvae have apparently long since pupated and exited the leaf of course. I wonder what the adult beetle eats – is there any significance to the round holes often but not invariably found in the attacked leaves?? I suspect this to be adult beetle damage.

And here at last is the Eriophyid mite that causes the felting lines above the veins, last seen on one leaf only at Bitchett Hill. Again although I looked a fair bit I only saw this on two patches of leaves, one a single line on a single leaf, the other patch two or three lines each on three close together leaves. Why is it in apparently such low numbers? Is it having a very bad time? How does it survive year to year when the leaves fall? Am I seeing very few survivors after two successive very hard winters? And are they confined to older trees? A definite mystery!

I also found just one mine that I initially thought might be a Stigmella – by one of the trees near the river as the road enters the village. However it could also be an aberrant mine from Orchestes fagi, and actually I think this is much more likely, and that's how I've logged it. Interestingly again the leaf has the round holes I am guessing is adult damage.

Here is one of the three apparently oldest trees, all with their heartwood under attack by fungal rots.

What a fantastic day!