More Hornbeam at Dene Park

Interesting to walk along the old western boundary of Princes Wood beyond Fox Wood, by the old Hornbeam bank to what is mapped as Claygate Wood, although there were not that many leaf-miners or galls in this area. I had expected more, because of the apparently long history of Hornbeams in this spot.

Again Phyllonorycter esperella, the Dark Hornbeam Midget, was actively present on the upper-surface of leaves, and I tried to find some caterpillars or pupae to rear on to adulthood. However I found neither for certain.

Here are two (one fairly active looking) mines of Phyllonorycter esperella on the upperside of one Hornbeam (Carpinus betulus) leaf. There often seems to be a brownish spot in the centre of an active mine, which could perhaps be frass. However I think the frass is deposited around the perimeter of the mine. The colour tends to be noticeably silver. The mine is said to be flat, and indeed rarely seems to have significant creases. It normally lies over at least one side vein. The outline of the mine is almost rounded, perhaps oval, of very variable size, but apparently not often controlled by the vein pattern.

This is an older mine from the summer, demonstrating the way the leaf has been "pulled up" into a trough by the mine as it tightens. As the mine decays, the leaf surface often seems to recover its integrity and level off. However in this case the "damage" seems more permanent and critical.

Here is another mine, perhaps younger, but broken open and with the leaf beneath looking very good. Perhaps this caterpillar is still at the sap sucking stage, or maybe it is a very shallow feeder. The leaf is also showing the midrib wrinkling associated with Aceria tenella mites.

The leaf on the right is showing an underside leafmine that is short enough to look like an active Phyllonorycter messaniella, perhaps rather unusual to see this so late in the season - unfortunately I didn't collect it. The shoot in the middle has got some good healthy winter buds on it, already developed.

The Hornbeams are starting to turn now, with this interesting pattern of individual leaves being very different in their colour changes, sometimes giving this beautiful pattern.