Identification & Distribution
Adult apterae of Lipaphis erysimi are small to medium sized yellowish green, grey green or olive green aphids, with a faint white wax bloom. In humid conditions they may be more densely coated with wax. The aptera (see first picture below) has two rows of dark bands on the thorax and abdomen which unite into a single band near the tip of the abdomen. The siphunculi are pale with dark tips. The body length of adult Lipaphis erysimi apterae is 1.4-2.4 mm.
First image: Lipaphis pseudobrassicae aptera, copyright Andy Jensen, Creative Commons (CC BY-NC-SA 2.0).
Second image: Lipaphis erysimi alate, copyright Alan Outen & Rothamsted Research, all rights reserved.
Alatae have a black head and thorax and a dusky green abdomen with black bands near the tip and conspicuous dark marginal sclerites. The body length of Lipaphis erysimi alatae is 1.4-2.2 mm.
- The first of the images above (taken in USA) actually represents the very similar Lipaphis pseudobrassicae (turnip aphid, mustard aphid), rather than the true Lipaphis erysimi with which it has often been confused. Lipaphis pseudobrassicae is correctly identified as such by Andy Jensen in AphidTrek, but not in BugGuide, or Wikipedia which use the same or similar images.
The second image above is of an alate Lipaphis erysimi from a culture maintained at Rothamsted Research, derived from individuals collected in the English midlands. Lipaphis erysimi has relatively shorter antennae and relatively longer siphunculi than Lipaphis pseudobrassicae, and can be separated from that species using a discriminant function. In 90% Lipaphis erysimi apterae, the 'length of antennal segment III + length of terminal process' is less than 2.4 times the length of the siphunculus. Lipaphis erysimi is confined to northern Europe, whilst Lipaphis pseudobrassicae has a near worldwide distribution, but is not found in Britain.
The clarified slide mounts below are of adult viviparous female Lipaphis erysimi : wingless, and winged.
Micrographs of clarified mounts by permission of Roger Blackman, copyright AWP all rights reserved.
The wild crucifer aphid does not host alternate. It feeds on various different Brassicaceae, including Brassica, Raphanus, and Sinapis spp., although it is not usually found on field Brassica crops. It lives on the undersides of leaves as well as on inflorescences, young shoots and growing points. Males have been found in some countries. Lipaphis erysimi is confined to Britain and northern continental Europe.
We especially thank Alan Outen, Bedfordshire Invertebrate Group, and Chris Shortall, Rothamsted Research, for permission to reproduce Alan's photo of a Lipaphis erysimi alate and for information about the colony.
Our particular thanks to Roger Blackman for images of his clarified slide mounts.
We have made provisional 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).