Phyllonorycter coryli and nicellii on Hazel

Now, at the start of July, there are quite a few of the first generation Phyllonorycter coryli (Nicelli) leaf mines in their early flat silvery stage are appearing on the upper side of the Hazel leaves. Sometimes there are multiple mines per leaf. The caterpillars seem quite small, a couple of mm long at this stage. It would probably be better to wait a couple of weeks to see if we can find some pupal cocoons in order to breed through. There may be some up-folding of the leaves already, and that somewhat darker more contracted stage of the mine surface is the one to wait for. These should fairly quickly metamorphose into the adult moths. Sadly I had no luck getting any adult moths out of these mines.

The caterpillars mine July and September-October, while the two generations of adult moths are May and August. By implication there should be a resting pupal stage from October through April. Presumably this is in the decaying leaves and then the litter on the forest floor. There should also be a brief pupal stage between July and August that is our target stage for collection. The pupae should be in cocoons in the opposite corner of the mines to the piles of frass.

There is also the significant possibility of accidentally collecting numbers of parasitoids instead of unparasitised pupae. It will be interesting to keep an eye out for Braconid and Ichneumonid wasps.

and a closer view:

and I did find just one possible example of Phyllonorycter nicellii (Stainton), the Red Hazel Midget, which mines the underside of the leaf. I think I was lucky to spot it, as I just saw the darkness of the leaf fold. I didn't think that it was necessarily typical, but it did clearly have the "nibbling" around the edge of the mine clearly visible on the upper surface of the leaf, so I doubt it was N. coryli. The species appears to have a similar life cycle timing to Phyllonorycter coryli, and I found a few more over the following weeks, but this is still very much the minority species in this particular wood.

The NBN atlas claims that "the mine [of Phyllonorycter nicelli] is usually between two side veins. The pupa is formed in a white cocoon in a corner of the mine. It is attached to both the roof and the floor of the mine. The frass is deposited in an opposite corner." This mine was on the edge of the leaf, so that the margin of the leaf rolled down and in, unlike the common depictions of the mine as arching up between two leaf veins, with the axis of the mine leading away from the midvein. Almost all the other mines I detected were of the more typical form described.

Again there are multiple Chalcid and Ichneumonid parasitoids recorded.

This is a more typically shaped mine for Phyllonorycter nicellii, photographed a few days later on the 5th. Note that the tent is in great condition, with multiple browner creases, typical of the Phyllonorycter genus and of this species, so I am fairly confident about the ID.

and this is the upperside of the leaf showing the shape of the mine more clearly and the significant upfolding of the leaf together with the apparently typical "edge of the mine" nibbling. The nibbling can however also be seen apparently in the (usually smaller, squarer?) mines of Parornix devoniella.

Training Toby at Leybourne

I had a shortish look around some of the mined leaves.

Phyllonorycter rajella on both Alnus glutinosa and Alnus incana (as pictured, on the underside of the leaf)

Phyllonorycter kellemanella = kleeemannella on Alnus glutinosa, one still with an active caterpillar.

Phyllonorycter stettinensis on Alnus glutinosa. The crease runs vertically up this photograph. The mine on the upperside of the leaf spills over a lateral vein.

Note how the brown discolouration has spread, but has not completely replaced the green. 

Fenusa dohrnii on Alnus glutinosa

Incurvaria pectinea on Alnus glutinosa

Phyllonorycter and Caloptilia on Field Maple

At the far end of the Access Trail woodland shaw, where we put the extra brick footings down the other year, there was a small Field Maple with a few folded leaf tip lobes that looked like Caloptilia mine follow-on folds.

This turned out to be Phyllonorycter acerifoliella, (Zeller, 1839), the Maple Midget, a bi-voltine leaf miner. The mines can be found in small numbers in May and, more frequently, in September and October. These mines are presumably partly the current generation of mines, and so some should really contain larvae or pupae that are about to over-winter.

The pupa should be blackish brown in a tight, thin-walled cocoon that is attached to the floor of the mine; all frass is accumulated in the opposite corner of the mine.

First seen from the upperside, then the underside:

and here is another example:

This is another, more recent mine, which I cannot identify, as it doesn't look at all like typical Phyllonorycter acerifoliella. It could possibly be Phyllonorycter joanissii from Norway Maple, which this mine closely resembles, but this is generally judged very unlikely. In the past Andy Banthorpe has identified this type of mine away from the edge as atypical Phyllonorycter acerifoliella.

Again, first from the upperside, then the underside:

a closer view:

Hopefully these Phyllonorycter acerifoliella folded leaf lobe mines will not be confused again with Caloptilia leaf lobe folds, as I first did!!

Now this looks more like a Caloptilia:

Viewed first from the upperside, then the underside:

On Field Maple, Acer campestre, in the UK this would seem to be most likely to be Caloptilia semifascia  (Haworth, 1828), the "Maple Slender". This is found on the Field Maple in the UK

The very early mine is a gallery leading soon to a small triangular or squarish blotch. Later the larvae move out to form up to three successive tubes or cones by folding the tips of leaves downwards, in which they live. On this plant there were usually only one or two folded leaf lobes per leaf. The larvae are said to be greenish with a lighter head.

The mines are supposed to occur in June - July and the ones shown here do generally look quite fairly old. Pupation is said to be in a flat, parchment-like, shining, yellowish white cocoon on either side of the leaf, but generally near the margin. I imagine that pupae are quite difficult to find in July(ish), and I haven't found any yet. The moth then flies until October, and after hibernating, again in May, before egg-laying.

However, another minor possibility on Field Maple is Caloptilia rufipennella (Hubner, 1796), which is found almost entirely on Sycamore and only rarely on Field Maple in the UK, although apparently on a wider range of Acers, including again Field Maple, on the continent. This species was only first identified on any Acer species in the UK in 1970, and is still a bit local in its distribution although spreading well. Because of its rarity on other hosts, at least according to current records, we can fairly discount it as a likely record in this case. It also has to be said that the information about host preference on different web-sites is quite contradictory in my view.

The initial feeding blotch mines are very difficult to find, and distinguish from other feeding marks, again in my limited experience, and I haven't identified one at all yet. 

A few mines on hawthorn and sallow

Phyllonorycter corylifoliella (Hubner, 1796) on Hawthorn, on a lush plant, heading down towards the Whetsted gravel pits, a fairly classic view of what is said to be a quite common leafminer, from what I can see on the internet. The second image is just a closer crop of the first.

and a closer view:

Here is another mine, again the second image is just a closer view of the first. An older version of the same leaf miner species, or more likely to be Ectodoemia atricollis, with maybe a narrow channel of a mine along the margin of the leaf to start with.

This next one might be a developing Ectoedemia mine, a full depth yellowish mine, with the larva still in it I think! There might be a bit of a thin mine along the edge. Again the second image is just a tighter crop. Ectoedemia atricollis, (Stainton, 1857), the pinch-barred pigmy, which does mine leaves from the end of August through to October.

and this one might be a better developed mine of the same species,

Here is a photo of a galled willow leaf.

Beech in Dene Park

The first Beech, Fagus sylvatica, trees I looked at had some old Phyllonorycter messaniella empty and browned mines, but further round on the north side, there were a couple of perhaps more recent and I think probable Phyllonorycter maestingella mines. And as usual there were some I couldn't make my mind up about.

I think this is pulled quite tight and is probably maestingella, lower side then upper side:

This (I think) is a second example:

Here are some old mines of what is probably Phyllonorycter messaniella.

Here is a new mine, with the caterpillar visible within it, next to a very old mine. There is no sign of any crease in the new mine.

However here is an old mine that still apparently shows sign of a central crease:

There were also some quite chunky brownish Stigmella mines, quite possibly Stigmella hemargyrella, as the egg seems to be away from the midrib. Notice the narrow start and first section of the mine, to the left, which apparently increases in size very abruptly.

Here is another example:

And a third, again starting at the leaf margin and finishing near the midrib, this time with a clear exit hole:

Nothing else, except the common leafhopper marks and the Hartigiola annulipes galls I think.

Late in Dene Park

A few mines about in the gloaming, getting a bit difficult to see!

On the Beech there were a few fairly long thin mines, all apparently deserted (!) of the Beech Midget, Phyllonorycter maestingella (Muller, 1764). I do wonder why this year I find so few occupied mines of this species, and I do seem to find more mines of P. messaniella on Beech, with its wider host range.

Access Trail

Wandered along the shaw on the normal Bourne walk as the light faded this evening, I looked at one of the small Field Maples at the far end and found a few few folded down leaf lobe tips. I wasn't sure whether these folds indicated a Caloptilia as I had first thought, or possibly Phyllonorycter acerifoliella (Zeller, 1839), the Maple Midget. In the end I think at least one leaf tip roll turned out to be the latter, although the revealed mine proved to be empty.

It is regarded as common with the mines occurring in July (presumably this one, hence emptied, with an exit hole) and October.

Eight Mallards overflew in a group. Not much else around, as it was getting very dark.

Fox Covert

Back to Dene Park, and diverting off to Fox Covert and the field beside it.

At the top of the field I found a few small folds at the tip of the lobes of Sycamore leaves, which I thought might be indicative of a Caloptilia species. This could be the Small Red Slender, Caloptilia rufipennella, found in the UK since the 1970s. The moth over-winters, perhaps in an evergreen such as Yew and reappears about spring. The mines are formed in sycamore leaves around, first as a small mine tucked into a vein axil, and you then get usually 3 "leaf tip folds - cones?" of increasing size in which the larvae continue to feed.

Eastern Bod Petryal

A short morning amble up past the white house in Fron Wyllt. On one of the Wych Elms, Ulmus glabra, there was a long, quite tubular Phyllonorycter mine, very much between two veins. suggesting the Elm Midget, Phyllonorycter tristrigella (Haworth, 1828). This one was showing only limited edge damage to the upper epidermis, as though it perhaps hadn't fully developed. One possible exit hole.

The mining is carried out in July and then in September/October. This one is presumably from the first generation of 2019?

It was unlikely to be Phyllonorycter schreberella, as this is an oval and less contracted mine, possibly across main veins. In addition this is less rarely found on Wych Elm, and also it is commoner in the south of the country (England and Wales), although the distribution certainly does reach North Denbighshire.

Interesting afternoon walk to the east across the Afon Clwyd, along a made track and down a path along the east track, then up through the spruce forest, and back along the Fisheries Road to the main Cerigg-y-drudion road - taking care to take to the verges to avoid the speeding cars.

Bod Petryal in the drizzle

Plenty of Mompha raschkiella mines on the Rosebay Willowherb along the circular path around Bod petryal. Apparently this is the only leafminer found on Rosebay, while there are a range of  other Mompha species on the true Willowherbs, Epilobium. 

The larvae can be found from the end of May to the end of July and from the end of August to the end of September.

The tunnels loop around cutting off tissues (until tissues turn reddish) a large yellowish patch mine is formed.

Fron Wyllt again

Interesting afternoon walk at Fron Wyllt, taking a quick look at the Beech leaves, Fagus sylvatica, on the trees which appear to be planted near the car-park, on both sides of the river. Toby is definitely gradually getting more used to my no-doubt boring stops to look at leaves!

I found about half a dozen relatively short Phyllonorycter mines which seemed to have a strong central crease. Some of these seemed fairly old and abandoned. This would fit in with Phyllonorycter messaniella, which seems to fold and distort the surface of the leaf quite strongly in most of the pictures shown. I saw one particularly long mine, still apparently with a central crease, but there are photos on the internet showing equally long mines that are identified as P. messaniella. These mines could be up against the midrib, or they could be away from it, mostly half way out towards the margin of the leaf. 

However the other possibility is a highly contracted long tubular mine which is said to have several pleats but these might look like just one, and I found three of these, two side by side on one leaf? So Phyllonorycter maestingella was confirmed, and I will come back to this later.


Phyllonorycter messaniella

Phyllonorycter messaniella (Zeller, 1846), Zeller's Midget, is also known as the Garden Midget - arbitrarily? 

According to UK leafmines, the mines are generally active in March - April, again in July and then October, although these dates seem rather tenuous (?). Perhaps its July to October? They don't really fit in with the idea that the third generation only occurs overwintering on the evergreen Holm Oak, December to March. On Beech and Hornbeam this species is said to be found on the lower surface between two adjacent veins, with a sharp fold.

Another more detailed description from the excellent Bladmineerders website is "oval, lower-surface tentiform mine, 9-14 mm long, mostly between two lateral veins. The lower epidermis with a single sharp fold (sometimes forked near its end). Pupa in very flimsy cocoon, that contains a bit of frass laterally and at the rear end".

Polyphagous on woody plants, not uncommon on Beech. However, the Dutch view is that the main host is Oak, although I haven't looked for it there yet. 

It was accidentally introduced into Australia and New Zealand, where it turns out to be regarded as a pest, mainly (and initially drastically) on introduced oaks, etc, but including on members of the native Southern Beech genus, Nothofagus. Initially it ran riot in New Zealand with an average of many mines per leaf until European parasites were introduced, when some degree of control was developed as would be found "naturally" in Europe. 

Phyllonorycter maestingella

The significantly longer mines on these leaves belong to this species, the monophyletic Beech Midget (Muller, 1764). The several folds may appear as one, and the silk is strongly contracted, often leading to a tubular appearance.

It has two broods, the adults flying late April to June, and again in August. The mines are therefore usually active in July and September to October. The insect then hibernates as a pupa, presumably on the ground.

Alder leafmines

Phyllonorycter klemannella, (Fabricius, 1781), the Dark Alder Midget 

The first and possibly much the commonest mine I found today was Phyllonorycter klemanella (=kleemannella), the Dark Alder Midget. I was only looking on a few lower branches of an alder on the north side of the Bourne opposite Easterfield Bungalow.

These mines were both away from the midrib, and also close to the midrib. They showed no strong creases (so the mines were not Phyllonorycter rajella, larvae June and July), and it is the right time for the second generation of these larvae in the year, July- August. The mines were not long and thin enough to be confused with Phyllonorycter froelichiella, which is also un-creased, but with grey larvae, usually a bit later in the year, such as September-October. All these are underside mines on Common Alder, as opposed to Phyllonorycter stettinensis, which is strongly creased, characteristically yellow-green and on the topside of the leaf over a vein, larvae May and July-August but can be as late as November.

There were active green fresh mines but there were also other older mines, some emptied, which might have been from the first generation, May-June, or already-hatched mines from the second generation. Here is a supposedly typical fresh oval mine of Phyllonorycter klemanella (=kleemannella). 

Here is another mine, from the upper side of the leaf.

Phyllonorycter stettinensis (Nicelli, 1852), the Small Alder Midget

I did also find two, or a few more, examples of Phyllonorycter stettinensis, on the upper side of the leaf. This is yellow green, with one strong central crease, the timing is right for the second generation  but in this photograph it is NOT over a lateral vein, as described in Bladmineerders. A second mine was over a lateral vein, so that is OK!

This mine is apparently much more typical, over the vein,

Phyllonorycter froelichiella (Zeller, 1839), the Broad-barred Midget

I may have found one or two examples of this leaf-miner, but it is a bit early for this particular species. Also this particular mine does look as though there is the start of a single crease in the mine, which would be unexpected in froelichiella, so maybe this is a misidentification. With this crease it could be rajella.

I need to check back, but I don't seem to have ever seen froelichiella for sure - I will check through as much as I can.

.Phyllonorycter rajella (Linnaeus, 17589), the Common Alder Midget

Why haven't I found this species on the leaves of this tree? The larvae should be found in June/July and more in September/October, and I would have expected to find it by now.

Heterarthus vagans ( ), 

This is a possible, but not definite, identification,

Lady Amherst's Drive

A quick visit to Lady Amherst's Drive in Goathurst Common this afternoon, parking in the small car park by the cross roads.

In a very brief moment or two I had a look at a few of the young Beech trees in among the sweet Chestnuts, and found Stigmella tityrella and Stigmella hemargyrella. There were also a couple of Phyllonorycter maestingella and one really old but possible Phyllonorycter messaniella.

I thought I might have found a couple of Parornix fagivora, but in the end I couldn't be sure - possibly just a couple of S. hemargyrella mines on the edge of the leaf.

A few "bump" galls as well.

The site is definitely worth another look though!

Trosley Country Park

I found one very likely Phyllonorycter tenerella (Joannis, 1915) Hornbeam Midget mine today - In this case much less than half the width of the available lamina between two side veins, and starting at the midrib running well over half the distance towards the margin. The mine was also inhabited, although having torn it open I may well have sealed the fate of this caterpillar to die before it achieved its further pupal and adult potential!

The picture below is of the mine from the upper-side of the leaf - well eaten and browned, narrow and tightly folded, and long. Interestingly there was some further feeding damage and even webbing at the ends of the mine - perhaps caused by something else, possibly a Tortricoid?

Phyllonorycter tenerella is a species of southeastern England, as well as of Europe. There are reasonable numbers of regular records from Kent, high in 2008 and 2009, as for other leaf-miners I think. David Solly seems to have been very good indeed at finding them over the years!

As far as other leaf miners go, there were also some (not many) Phyllonorycter esperella mines on the upperside of the leaves and quite a few Stigmella probably microtheriella mines running largely up and down the veins. I also saw a few galls caused by what I have called "vein mites" Aceria tenella (Nalepa).

The Hornbeams at Trosley are quite variable, some young, some older, some coppiced, some maidens. This one is a moderately young Hornbeam, apparently a maiden, never been coppiced. It does look possibly a bit root-bound!

This one is another potential maiden, but quite a lot older! This suggests that there hasn't been much coppicing going on in this are of this particular woodland for quite a long time. This might match the history of the wood as a private estate, rather than a worked woodland.

There is an older picture of the grounds on the internet, of unknown date, but indicating their amenity nature at that time.

I saw two trees that were covered in fruit, and wondered why the distribution of fruit was so unequal across the woodland. I collected a couple of dozen fruit to see if they could be germinated.

Hazel Wood

Walked down from West Peckham in somewhat murky weather, and into Hazel Wood which had regrown and thickened up considerably since its last coppicing!

The Hornbeam and Oak in the first part of the wood are quite traditional. Further down there is more Sweet Chestnut and Aspen. Birch and Hazel are scattered throughout.

Some of the older Hornbeam and Sweet Chestnuts were in trouble:

On the Hornbeam there wasn't a lot of caterpillar damage, and there were relatively few leafminers and galls. There seemed to be reasonable numbers of probable Stigmella microtheriella and Phyllonorycter esperella, with a very small number of probable Phyllonorycter tenerella.

It was interesting to see that what might have been taken for old summer mines of Phyllonorycter messeniella that were indicated by shortly oblong brown patches had in fact been caused by mines of probable Stigmella microtheriella "cutting off" oblongs of tissue by running up one vein, cutting across from that vein to another, and then down that other, and then cutting back to the first - I need to watch out for this rather unexpected pattern, seen at least three times today!

I was surprised not to see any mite galls in the leaf vein axils, and overall I would say that it was a relatively disappointing walk from both the leafminer and gall point of view. The terrible light and miserable murky conditions did NOT help.

Monty struggled a bit with his back legs.

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.