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Wayfaring tree - sedge aphidIdentification & Distribution Biology & Ecology Damage & Control
Identification & Distribution:Ceruraphis eriophori is a medium-sized, oval, aphid. The antennae are short, only 0.29-0.37 times their body length. The dorsum of the fundatrix on the primary host (shown below) has extensive dark sclerotization. The same is true for Ceruraphis eriophori aptera on their secondary host. The siphunculi are black and are more than twice as long as the very short conical cauda. The body length of the Ceruraphis eriophori fundatrix is 2.5-3.0 mm, and that of the aptera on the secondary host is 2.0-2.8 mm.
The clarified slide mounts below are of adult viviparous female Ceruraphis eriophori (on primary host) : wingless, and winged.
The wayfaring tree - sedge aphid host alternates between Viburnum spp. (especially wayfaring tree (Viburnum lantana)) and various sedges (Carex spp.). On the wayfaring tree the aphid lives in a pseudogall of curled leaves. Ceruraphis eriophori is found in Europe and northern India and has been introduced to North America.
Biology & Ecology:
The overwintering eggs on wayfaring tree hatch in spring, and the nymphal fundatrices feed on the young shoots. This makes the leaves shrivel and curl downwards, thus enclosing the aphids in a pseudogall. These pseudogalls are very conspicuous on the tree in spring (see pictures below).
The developing fundatrices are greyish before maturing to the black adult fundatrices (see first picture below). The fundatrices then produce characteristic violet-coloured nymphs (see second picture below) which fill the gall.
Ceruraphis eriophori produce large amounts of honeydew, which can make the galls and surrounding leaves very sticky.
Sometimes (but not always), Ceruraphis eriophori are attended by ants feeding on the excreted honeydew. We have found two species of ants attending Ceruraphis eriophori, jet black ants (Lasius fuliginosus) (see first picture below) and a Myrmica sp. (see second picture below).
Where ants are present, we have found much larger colonies of Ceruraphis eriophori in the galls. All the violet-coloured nymphs mature to alates (see picture below) which migrate to the secondary hosts.
Unfortunately we have not yet found Ceruraphis eriophori on their secondary host (hence no pictures), although it must be fairly common given the abundance of the species on the primary host in some locations.
There seems to be very little published information on Ceruraphis eriophori. In New Brunswick, USA MacGillivray(1960) compared the taxonomy and biology of the invasive Ceruraphis eriophori with the indigenous Neoceruraphis viburnicola. Both could be found in spring and autumn in the curled leaves of their Viburnum primary hosts.
Damage and control
Ceruraphis eriophori is not considered to cause any economic damage in Europe. However, in America it is an alien invasive species, and is considered a potential threat to the long term survival of the endangered false hop sedge (Carex lupuliformis) (Environment Canada, 2014 ).