Myzaphis rosarum

Identification & Distribution:

Wingless adults of Myzaphis rosarum are yellow-green to green with no pleural stripes (cf. Myzaphis bucktoni which has a pair of broad dark stripes converging at the level of the siphunculi). The antennal tubercles are low, but the median frontal tubercle is rectangular and strongly projecting (cf. Myzaphis bucktoni which has the median tubercle rounded). The dorsal cuticle is pitted all over. The siphunculi are quite long, and are slightly swollen and dark-tipped. The cauda is long and conspicuous. The body length of Myzaphis rosarum is 1.2-2.4 mm.

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

Myzaphis rosarum live all year round on wild and cultivated roses, especially climbers, and frequently also on shrubby Potentilla species. There is no host alternation. They feed mainly along the mid-ribs on both the upper and undersides of young leaves. In Europe oviparae and small dark apterous males appear in November. Myzaphis rosarum is native to Europe, but is now almost cosmopolitan.

Biology & Ecology:

Like many aphid species, Myzaphis rosarum abundance can vary greatly from year to year, hence the standard texts (being based upon relatively few observations) are not always a reliable guide. We only found Myzaphis rosarum for the first time in early April 2015, despite the fact it is regarded as a common (albeit minor) pest species.

Jaskiewicz (2003) describes the species composition and number of aphids on rose bushes in urban conditions over three years. Myzaphis rosarum appeared on roses late May to early June, reaching maximum numbers in June or early July. They disappeared from one site in late summer, but persisted at the other into December. Lesser rose aphids comprised 6-26% of the aphids feeding on roses.

We have also found Myzaphis rosarum may remain on roses into mid-winter, albeit in the very mild winter of 2015-16. The picture below shows them in late January on garden rose in Alfriston, East Sussex.

These aphids were present as parthenogenetic viviparae.

Myzaphis rosarum also occurs on Potentilla (see pictures below).

Other aphids on same host:

Myzaphis rosarum has been recorded from 32 Rosa species.

Blackman & Eastop list about 70 species of aphid found feeding on Rosa (rose) species worldwide, and provide formal identification keys (Show World list).

The genus Rosa contains perhaps a hundred species, plus hybrids thereof, and thousands of cultivated varieties of 'garden' & agricultural roses. Blackman & Eastop (1984) list thirty-or-so species of aphids that feed on cultivated 'roses', worldwide (Show World list).

Of those aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).

Damage and control

Myzaphis rosarum is often hidden from view amongst furled leaflets, and may only be noticed when populations are unusually large. It is not considered particularly damaging.

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).

Useful weblinks

References Jaskiewicz, B. (2003). The species composition and number of aphids on the shrubs Pinus mugo Turra and Rosa sp. in urban conditions. Electronic Journal of Polish Agricultural Universities, Horticulture 6(2). Full text