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GALL FORMING APHIDS |
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| When
I saw plant galls for the first time I wanted to know what species there
were to be found basically, and so I started collecting anything that looked
like a plant gall. Boxes full of them I have now. Nowadays I think it is
better for me to take pictures (digital or slides) and when you are interested
in the gall maker itself, it is a good idea to try to get the inhabitants
to emerge from the galls. The list of species described below are gall makers
and their hosts, from species that I myself or another gall studying person
has seen. A description is given and, where possible, a picture. For people
who are interested in the Dutch distribution of pant galls can soon take
a look at the database we are preparing for this website. Since the subject
of plant galls becomes more popular only recently, we do not have yet such
an extended database. Any contribution is welcome! |
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| Adelges
abietis is a rather common species on spruce (Picea abies).
The needles are shortened and thickened and are spaces closely together,
which is why it lookes a bit like a cone. In August or September the galchambers
open and the aphids emerge. There are usually two or three galls on one
branch, at the base or outher parts of young shoots. The young shoots remain
to grow, also from the gall. |
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 (Pictures:
T.J.M. Janson)
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| Adelges
nordmannianae, is a species that seen on Picea orientalis
every now and then. The gall is much more compact than the
previously mentioned Adelges-species. It is describes as being rather
rare for England, but I don't think this is the case in the Netherlands.
I have seen the species in the Hortus Haren (Gr.) and Theo Janson and
Leo Goudzwaard (pinetum Schovenhorst, Putten) made the picture's you can
see on the right. The gall grow from the short side-branches and also
consist of strongly (at the base) thickened needles.
The whole of the branch disappears in the gall and the tip ends of the
neadles are hardly developed. The gall are 6 tot 8 mm tall. Abies-species
are in-between host species, but the leafaphis does not develop galls
on these hosts (DvL). |
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(Picture: T.J.M. Janson)
(Picture: L. Goudzwaard)
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| Adelges
virides (sacchiphantes) is a wide spread aphid on Picea abies
that causes galls to form at the ends of branches, but with a little tip
of the branch, or a lot of branch on top of the gall. The branches on top
of the gall remain alive and growing. The needles swell at their base and
grow together. Behind every broadening needle is a cavity, where the aphids
live. The cavity opens en closes several times. The gall is bald and has
the appearance of a pineapple and becomes about ten millimeters wide. Around
the edged of the cavities there is usually some red colouring. I made this
picture in Grachen, Switserland. |
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| Aphis
rumicis - The leaves are irregularly curled downwards from the edges
and has a wrinkled appearance because of extra tissue in between the
veins. The species is common on Rumex obtusifolius and also occurs
on other big-leave Rumex-species. The aphids are black. |
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(Pictures: B. Kabbes) |
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| Brachycaudus
tragopogonis is an aphid that makes the leaves of Prunus spinosa
wrinkle downward. This usually occurs on young shoots. Inside the curl are
many aphids. |
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| Cryptomyzus
ribis is an aphid which causes red and yellow coloured pouches to
appear on the upper side of the leaves of Ribes rubrum and R.
americanum. The pouches blend to bigger pouches. The gall is said to
be common. This picture was taken in Fryslan and I have seen a specimen
myself in Stedum, Groningen. |
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(Picture: B. Kabbes)
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| Eriosoma
lanuginosa on Ulmus minor induces an impressive gall which
uses the entire leaf to form the gall. A large sack appears that is covered
with short hairs. In the beginning the gall is pale green and often also
slightly red. When the gall becomes mature, the gall bursts open and the
aphids are free to leave. Inside, the walls are covered with honeydew. After
the aphids have left, the gall turns brown and will stay on the tree until
the next year. |
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Pictures: R.J. Koops
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| Eriosoma
ulmi is one of the leaf roling aphids on elm - Ulmus. One
side of the leaf is inrolled and thickened, causing halve or sometimes the
whole leaf to be galled. The leaf roll colours pale green or white-green
and contains aphids with wax. The aphids are first green and later brown.
Common. |
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Gilletteella
(Adelges) cooleyi
causes long shaped deformations on different species of Picea.
On the many planted trees of Picea sitchensis in the Netherlands
the gall is very common.
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Pemphigus bursarius - On Italian or Black Poplars many gall forming
aphids can be found and most of them are really spectacular. Pemphigus
bursarius creates a major enlargement, usually on the leaf stem. |
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| Pemphigus
populinigrae causes galls on the midrib of Populus
nigra. On the upperside of the leaf is a elongate pouch, about
one cm high and several cm long. The gall is pale green to red. The opening
is below and in June - August the aphids emerge. The winged aphids are dark
green and the nymphs are grey. |
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| Pemphigus
spyrothecae - The leaf stalk of Populus nigra is broadened
and winded into a spiral. The edges of every wind is growing tight
together en thus closes the gall chamber. The gall can become to 30 mm long
and 12 mm wide. Sometimes the galls are coloured red. The species is described
to be common. The gall contains wingless aphids in July, and some aphids
with wings in August. |
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| Tetraneura
ulmi causes beautiful stalked,club-shaped galls on Elm (Ulmus)
(Redfern, Shirley, Bloxham, 2002), usually on the upper side of the leaf
blade, away from the midrib. When the galls are fully developed the aphids
leave through a hole near the base of the gall on one side of the club.
The galls become 7 to 15 mm tall and the leaf thickens and turns yellow
around the stalk. The aphids are waxy, grey-black above, green-yellow
below. Locally the aphids are common.
When the galls are immature they resemble green peas... |
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Picture: A. van Vugt
Picture: Marja Garrelds
Pictures: R.J. Koops
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(Pictures:
T.J.M. Janson) 
