The Sitobion fragariaeaptera is dirty yellowish green (see first picture below), with small brown intersegmental sclerites on the abdominal dorsum. The antennae are about the same length as the body, with the basal segments paler than the rest. The siphunculi are usually entirely black, although they may have paler bases on the primary host. They are 1.8-2.7 times longer than the pale pointed cauda (on blackberry cf. Macrosiphum funestum, which has the siphunculi 2.5-3.5 times the length of the cauda; on grass cf. Sitobion avenae, which has the siphunculi 1.1-1.5 times the length of the cauda). The body length of Sitobion fragariae apterae is 1.6-3.0 mm long.
Sitobion fragariaealates (see second picture above) have a pattern of dorsal dark intersegmental markings that is usually more extensive than in Sitobion avenae.
Micrographs of clarified mounts by permission of Roger Blackman, copyright AWP all rights reserved.
The clarified slide mounts below are of adult viviparous female Sitobion fragariae on the secondary host (grasses): wingless, and winged.
The blackberry - grass aphid host alternates from blackberry (Rubus fruticosus agg.) and occasionally other Rosaceae to grasses (Poaceae) especially Holcus spp. and some sedges (Carex spp). Sitobion fragariae eggs hatch in spring and the young nymphs feed on the breaking buds. Colonies build up and in summer alates migrate to cereals and grasses. A return migration takes place in autumn.
Other aphids on same host:
Sitobion fragariae has been recorded from 11 Rubus species.
Our particular thanks to Roger Blackman for images of his clarified slide mounts.
Whilst we make every effort to ensure that identifications are correct, we cannot absolutely warranty their accuracy. We have mostly made identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994) and Blackman & Eastop (2006) supplemented with Blackman (1974),Stroyan (1977),Stroyan (1984),Blackman & Eastop (1984),Heie (1980-1995),Dixon & Thieme (2007) and Blackman (2010). We fully acknowledge these authors as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure provided by Blackman & Eastop (2006).
Have an interesting aphid for you, what appears to be a Sitobion. It
was found on Wall Barley, Hordeum murinum, on a small pier at Newlyn
today. 10.06.14. SW 46490 28497. Juveniles quite orange in colour.
Few adults, mostly juveniles on each inflorescence, grass also looked
like it was going over, becoming dry and purplish.