Back on May 5, spring was cooking along; flowers were opening on the Virginia bluebells that I had completely forgotten we had planted among the ostrich ferns under the old apple tree last year.
But a few days later we had a setback, in the form of some snow that fell on the night of the 8th, into the morning of the 9th.
The snow melted away, but then we had a couple of frosts, which presented even more of a threat to the flowers and tender young leaves that had just opened up. The last one (I’ve decided it was the last one) was on the morning of the 14th. Amazingly, the flowers made it through all this pretty much unscathed, which was especially surprising with the peaches.
We tucked the asparagus patch in with blankets each night, which turned out to be worthwhile, since the two stalks we missed on the first night got frostbitten and turned to mush. Otherwise, the main casualties were the sensitive and interrupted ferns in the woods; some maple leaves will end up a little disfigured but have now resumed expanding. Spring is now back in full swing, and everywhere are new leaves presenting blank canvases for leafminers and other leaf-feeding insects to make their marks.
One plant I’ve been watching closely is the honeyberry (Caprifoliaceae: Lonicera caerulea), because this and other honeysuckles are the hosts for Aulagromyza cornigera (Agromyzidae), one of the first leafminers to show up apart from those that overwinter as larvae. This afternoon, there it was: a lone A. cornigera larva etching its characteristic white trail with discrete black frass grains.
In just a few days, the mine will be complete…
…and the larva will pop out of the leaf, drop to the ground, and form a puparium…
…not emerging as an adult until next spring.
So that brings the “leafminers in my yard” total to nine so far this spring. It is the first one to arise from an egg laid this year, not counting the Chrysoesthia sexguttella mines that are now becoming abundant on the lambsquarters in the hoop house. Those larvae are the progeny of adults that emerged in early April, but I didn’t see an adult of that species outside the hoop house until last week, so they are more than a month ahead of schedule.
In my first post about the leafminer yard list, I said there were larvae of both Argyresthia thuiella (Argyresthiidae) and Coleotechnites thujaella (Gelechiidae) overwintering in the arborvitae hedge along the road. I said this with confidence because there are mines all over the trees; although the mines of the two species are indistinguishable, I have seen adults of both on that hedge, and I have reared C. thujaella from some of the mines. The truth is, though, I have never found a definite mine of A. thuiella there or anywhere else, and I’ve been watching this spring to see if I can spot some larvae. Although the mines of the two species are identical, they can be identified when larvae are present because A. thuiella larvae are green while those of C. thujaella are brown. Today I finally noticed some fresh, whitish mining extending out from the old, brown mines that were made last fall.
(The difference was more apparent to my eyes than to my camera’s sensor.) But alas, every mine I photographed with bright backlighting had a brown larva inside. The green larvae of A. thuiella remain elusive.
For a consolation prize, I found this sawfly laying eggs in some of the needles.
I surmised based on the host plant that she belongs to the genus Monoctenus (Diprionidae), which Dave Smith confirmed. There are at least three Monoctenus species in eastern North America, but there is no key that can be used to identify them. Dave says, “The genus needs study. The one in the Northeast is usually called M. suffusus, I’ve called the one I get around here [northern Virginia] M. melliceps. I’ll have to wait till I get back to the Museum [the Smithsonian, which of course is closed due to COVID-19] to check. One would think this might be an easy project, but it will take a lot of dissecting saws [ovipositors] and male genitalia.” For what it’s worth, M. suffusus is the only name that has been linked to arborvitae (Thuja occidentalis); this species has also been reported to feed on eastern redcedar (Juniperus virginiana). Monoctenus melliceps (which also occurs in Massachusetts) has not been associated with any host, and M. fulvus (a midwestern species) has only been reported from eastern redcedar. I’ve never seen a Monoctenus larva, but I’ll be watching for them now. My only previous experience with Monoctenus was having a male emerge from an arrowwood plant Julia and I had dug up, potted, and bagged in a failed attempt to rear adults of the stem-mining moth now known as Marmara viburnella.
And on the foraging front, the last couple of weeks have added several more plants from the yard to our menu:
36. Rhubarb (Polygonaceae: Rheum × hybridum) – petioles
37. Asparagus (Asparagaceae: Asparagus officinalis) – shoots
38. Watercress (Brassicaceae: Nasturtium officinale) – leaves
39. Bull thistle (Asteraceae: Cirsium vulgare) – roots
40. Lesser burdock (Asteraceae: Arctium minus) – roots
41. Sea kale (Brassicaceae: Crambe maritima) – leaves
42. Maple-leaved goosefoot (Amaranthaceae: Chenopodiastrum simplex) – leaves
43. White sweet clover (Fabaceae: Melilotus albus) – leaves
44. English plantain (Plantaginaceae: Plantago lanceolata) – leaves
45. Jewelweed (Balsaminaceae: Impatiens capensis) – leaves
46. Groundnut (Fabaceae: Apios americana) – tubers
47. Ostrich fern (Onocleaceae: Matteuccia struthiopteris) – fiddleheads
I’ve only tried groundnut a couple of times in the past because it’s usually hard to dig up and there is no guarantee that the tubers will be big enough to make it worth the effort. However, we’ve allowed the plants to spread into our main strawberry patch over the past few years, with the result that we got several meals’ worth simply by weeding the strawberries this week. They’re delicious, with a flavor somehow halfway between peanut and potato.