Wrinkled Black Galls on Poplars

[Frederick W. Schueler]

Everyone,

Here's a draft of an article I'm working on for the North Grenville
Times about a kind of aphid-made gall which came as a complete surprise
to me last autumn. I'd like to know if these are known to others, and
maybe trees of various Populus species could be checked to see if
they're decorated with these galls.

fred.
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Mordwilkoja vagabunda – I’d never heard of such a thing, even under the
equally implausible-sounding English name of “Vagabond Poplar Gall
Aphid” until 22 November 2023 when I was checking things out on the
sandy field beside the paved lot of Mark’s Work Warehouse in the
Colonnade Mall. The small Cottonwood saplings around the lot were
generously decked out with shiny wrinkled black lumps. I’d never seen
anything like these, but on facebook Oliver Reichl provided a link to a
poster of tree galls, which allowed me to identify these as a product of
this species of Woolly Aphid in the tribe Pemphigini of the subfamily
Eriosomatinae.
Since then we’ve seen these galls nearby at Ryans Well Drive, and in
similarly disturbed habitat along Centennial Road north of Brockville,
and behind Jonsson’s Your Independent Grocery in the Kemptville Mall.
<<They’re said to be on both Cottonwood (Populus deltoides) and Aspen
(P. tremuloides), but we’ve seen them only on Cottonwoods>>
The Aphids hatch from eggs in last year’s galls and as they feed on the
expanding tips of the twigs, they induce the large irregularly shaped
galls, and feed and reproduce asexually inside them. Several generations
occur within the folds of the gall, and as many as 1600 individual
aphids have been reported from a single gall. They are called
“vagabonds” because, in early summer, a winged generation leaves the
galls and flies to a summer host. These hosts are not well known, but
Loosestrife is an important alternate host in some places. After a
couple or few asexual generations on the alternate host, a sexual
generation of the Aphids flies back to the galls, and mates and lays
overwintering eggs. The galls remain on the twigs, and are more
conspicuous after the leaves have fallen.

<<need a final paragraph>>

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---------Frederick W. Schueler & Aleta Karstad ------------ Fragile
Inheritance Natural History - https://fragileinheritance.ca/ FI
Newsletter -
https://clt1233162.benchmarkurl.com/c/v?e=15E5037&c=12D10A&t=0&l=53EF5F06
2022 annual letter: https://clt1233162.bmeurl.co/EFE49F7 6 St-Lawrence
Street Bishops Mills, RR#2 Oxford Station, Ontario K0G 1T0 on the Smiths
Falls Limestone Plain 44.87156° N 75.70095° W
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[Frederick W. Schueler]

On 10-Aug-24 10:17 p.m., Frederick W. Schueler wrote:
> <<They’re said to be on both Cottonwood (Populus deltoides) and Aspen
> (P. tremuloides), but we’ve seen them only on Cottonwoods>>

* we checked one site on Centennial Road this noon, and there were galls
on Aspen, so we've seen them on both species which are known as hosts.
Behind the Independent store in Kemptville they were on the Cottonwoods,
but not on Balsam Poplar which were mixed in with the Cottonwoods.

fred.

------------------------------------------------------------
---------Frederick W. Schueler & Aleta Karstad ------------
Fragile Inheritance Natural History - https://fragileinheritance.ca/

[Frederick W. Schueler]

On 10-Aug-24 10:17 p.m., Frederick W. Schueler wrote:

> Here's a draft of an article I'm working on for the North Grenville
> Times about a kind of aphid-made gall which came as a complete surprise
> to me last autumn.

* now published with a final paragraph - Schueler, Fred. 2024. Wrinkled
Black Galls. North Grenville Times, 12(33):7, 22 August 2024 – (photo
by Aleta Karstad) https://ngtimes.ca/wrinkled-black-galls/

fred.
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