Cryptomyzus korschelti

Identification & Distribution:

Cryptomyzus korschelti apterae, on their secondary host, are pale greenish-yellow with a bright green median stripe and further green mottling over the dorsum. The dorsal body hairs are thick and capitate, much longer than the basal diameter of the third antennal segment, and arising from tuberculate bases (cf. Cryptomyzus stachydis where dorsal body hairs are mostly shorter than the basal diameter of the third antennal segment). The siphunculi are distinctly swollen on the distal half, and are 3.1-3.9 times the length of the cauda (cf. Cryptomyzus ribis which has siphunculi 2.3-3.1 times the length of the cauda and Cryptomyzus galeopsidis which has siphunculi 1.1-2.1 times the length of the cauda). The body length of Cryptomyzus korschelti apterae is 1.6-2.9 mm.

Cryptomyzus korschelti alatae (see second picture above) have a large trapezoid dorsal abdominal patch, and have 38-57 secondary rhinaria on antennal segment III, 5-27 on segment IV and 0-14 on segment 5. The micrograph below is a lateral view of an apterous Cryptomyzus korschelti in alcohol.

The clarified slide mounts below are of adult viviparous female Cryptomyzus korschelti : wingless, and winged.

Micrographs of clarified mounts by permission of Roger Blackman, copyright AWP all rights reserved.

The woundwort aphid host alternates from alpine currant (Ribes alpinum) to hedge woundwort (Stachys sylvatica). On currant they live beneath red or yellow leaf blister galls. Cryptomyzus korschelti is widespread in Britain and Europe eastward to central Asia.

Other aphids on same host:

Primary hosts

Cryptomyzus korschelti has been recorded from at least 16 Ribes species.

Blackman & Eastop list 14 species of aphid as feeding on alpine currant (Ribes alpinum) worldwide, and provide formal identification keys.

Of those aphid species, Baker (2015) lists 12 as occurring in Britain: Aphis grossulariae, Aphis schneideri, Aphis triglochinis, Cryptomyzus galeopsidis, Cryptomyzus heinzei, Cryptomyzus korschelti, Eriosoma anncharlotteae, Hyperomyzus lactucae, Hyperomyzus pallidus, Hyperomyzus picridis, Hyperomyzus rhinanthi, and Nasonovia ribisnigri.

Secondary hosts

Cryptomyzus korschelti has been recorded from 7 Stachys species.

Blackman & Eastop list 7 species of aphid as feeding on hedge woundwort (Stachys sylvatica) worldwide, and provide formal identification keys.

Of those aphid species, Baker (2015) lists 4 as occurring in Britain: Aulacorthum solani, Cryptomyzus galeopsidis, Cryptomyzus korschelti, and Cryptomyzus ribis.

Acknowledgements 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).

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