Alder leafminers and mite galls at Haysden Country Park

Had a very short (but quite productive) hour at Haysden, where we went along the path towards the Flood Storage Barrier, looking primarily for Alder Leafminers and Galls. There were one or two fair sized Alders by the Shallows (as in the photo below) and then a good line of them along the Straight Mile. There were also a few young plants by the weir at the end of the Straight Mile. All were the Common Alder, Alnus glutinosa.

There were some Agromyza alnivora, and some galls on the leaf surface. The first I saw were small lumps scattered over the upper leaf surface, and slightly "mushroom-shaped" so might have been Eriophyes (Phytoptus) laevis. Even the galls close to the midrib were not confined to the vein axils.

The second type, further along the Straight Mile, were bumps along the midrib specifically in the vein angles, opening below, so were probably Aceria nalepai (Eriophyes inangulis). The usual leafhopper damage is also visible again.

With the Pouch Gall Acalitus brevitarsus, also seen at this site as well as at Leybourne, this brings me up to all the three mite types mentioned in Redfern and Shirley now hopefully identified.

The rusty-brown hairs on the underside of the galls were nice and clear, if a bit dark here.

Also widespread was this rust fungus, mainly on the underside of the leaves, possibly Melampsoridium alni, betulinum or hiratsukanum. M. alni is apparently only found in Asia, while M. betulinum has been noted in the UK (Scotland?) in the past, for example causing a bit of an outbreak in the 1990s. The last of these however is perhaps most likely, a newly introduced rust, since about 2000, potentially causing early defoliation and thus some economic impact on Alder species, particularly Alnus incana.

Going back to the Leafminers, here is what might be the top surface indications of Phyllonorycter kleemannella = klemannella, the Dark Alder Midget, nominally at least small, oval and often away from the midrib. The larvae are supposedly found in May/June and July/August, quite a lot earlier than this particular record, but the Dutch suggest there may be \a third generation increasingly recently.

This "cutout" might have been caused by an earlier leafminer scar that has dropped completely out, and if so, the long and thin shape suggests that it might have been Phyllonorycter froelichiella, the Broad-barred Midget. There are other possibilities though, and even kleemannella = klemannella can be long and thin and look like froelichiella....

As well as probable Aceria nalepai galls, this leaf might just be showing a leaf-mine of Caloptilia falconipenella, as it is right on the margin of the leaf and shows a bit of turning over of the margin. This moth is however nationally scarce B, so the mine might be of something else.