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Identification of rose aphids

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

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. Of those aphid species, Baker (2015)  lists 12 as occurring in Britain: Chaetosiphon fragaefolii,  Chaetosiphon tetrarhodum,  Longicaudus trirhodus,  Macrosiphum euphorbiae,  Macrosiphum rosae,  Maculolachnus submacula,  Metopolophium dirhodum,  Myzaphis bucktoni,  Myzaphis rosarum,  Rhodobium porosum, Sitobion fragariae  and Wahlgreniella nervata. 

  • Bell et al. (2015)  (Appendix S2) have also published an "annotated checklist of aphids present in the UK". We discuss some of the reasons for the differences between Baker's and Bell's lists in our rare aphids page. 

The species below are those we have found most frequently, listed in rough order of abundance on rose. In northern Europe Rhodobium porosum is only found on roses in glasshouses.

Ways to control aphids on rose are given below. 

 

Macrosiphum rosae (Rose aphid)

Adult Macrosiphum rosae apterae are green or deep pink to red-brown. The antennae and sometimes the head are dark, as are the ends of the tibiae and femora. The abdomen may or may not have small marginal sclerites and antesiphuncular sclerites. The siphunculi are black and bent outwards and are reticulated on the apical 10-17%. They are about 0.27-0.41 times the body length and 1.9-2.4 times the length of the cauda. The cauda is pale yellow. The adult aptera of Macrosiphum rosae is 1.7-3.6 mm long.

 

Macrosiphum rosae alatae have conspicuous black sclerites along the sides of the abdomen. They also have green and red colour forms. Immatures are similar in appearance to the adult apterae, but the cauda is not developed and the siphunculi are dusky, not black.

 

The rose aphid usually overwinters in the egg stage on rose bushes (its primary host), although in mild winters some adults may continue to reproduce parthenogenetically. In spring they colonise the young growth of rose, and produce large numbers of alates. These mostly migrate to their secondary hosts, teasels (Dipsaceae) and valerians (Valerianaceae). However, colonies can be found all summer on rose and the species is an important horticultural pest. Macrosiphum rosae has a worldwide distribution.

Read more... 

 

Macrosiphum euphorbiae (Potato aphid)

Macrosiphum euphorbiae apterae are either green with a darker green longitudinal stripe or red (see pictures below), and often rather shiny. Their eyes are reddish, and the antennae are darker towards their tips. Their femora are brownish and rather pale with the apices not dark or only slightly so. The siphunculi are pale sometimes with the tips darker, but not as dark as the tips of the tibiae. They are reticulated on the apical 13-20% and are 1.7-2.2 times the length of the cauda. The cauda is rather pointed and not constricted. The body length of Macrosiphum euphorbiae apterae is 2.0-4.0 mm.

 

The alate has pale greenish to yellow-brown thoracic lobes, with only the antennae and siphunculi noticeably darker than in the apterae.

The potato aphid is a common and highly polyphagous species. It is often a pest on various crops such as potato (Solanum tuberosum), lettuce (Lactuca sativa) and beets (Beta vulgaris) as well as on numerous garden ornamentals. Macrosiphum euphorbiae is a vector of about one hundred plant viruses. The species originates from the north-eastern USA where it produces sexual forms and host alternates with rose (Rosa) as its primary host. Elsewhere it usually overwinters as viviparae. Aphid numbers increase rapidly from early spring, and alates spread infestations to other plants. It is an especial problem in unheated greenhouses. Macrosiphum euphorbiae was introduced to Europe about 1917 and is now cosmopolitan.

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Chaetosiphon tetrarhodum (Hairy rose aphid)

Chaetosiphon tetrarhodum adult apterae (see first picture below) are pale green to yellow-green or occasionally reddish. The head is rather smooth with few if any spicules. The antennae are short, only 0.6-0.8 times the body length. The dorsal cuticle is densely covered with flat warts giving it a wrinkled appearance. Each abdominal segment bear 5 pairs of capitate hairs. Their siphunculi are 1.1 to 2.5 times longer than the cauda. The body length of Chaetosiphon tetrarhodum is 0.7-2.1 mm, with the smallest individuals in mid-summer.

 

Winged viviparae (see second picture above) have a dark head and thorax, a black central patch on the abdomen and dark wing veins. Oviparae are dark olive-green and the apterous males are small and dark.

Chaetosiphon tetrarhodum is found on various species of roses especially the Japanese rose (Rosa rugosa). In spring they can be found on the shoot tips, young leaves and developing flower. Later in the year they can be found singly or in small groups on the undersides of mature leaves. Sexual forms occur in autumn. The distribution of Chaetosiphon tetrarhodum is worldwide.

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Metopolophium dirhodum (Rose -- grain aphid)

The adult apterae of Metopolophium dirhodum are medium-sized spindle-shaped aphids which range from green to yellowish green, with a brighter green longitudinal mid-dorsal stripe (see pictures below). The antennae are about 0.75 times the body length, and are mainly pale apart from the apices of segments III-V, and parts of segment 6 which are dusky or black. The siphunculi are long and pale, with slightly dusky tips. The cauda is pale. The body length of Metopolophium dirhodum apterae is 1.6-2.9 mm.

 

The alate is green and does not have any dark markings.

The rose - grain aphid host alternates from rose (Rosa sp) as the primary host in spring and early summer to cereals and grasses, especially wheat, barley and maize, as the secondary host. In mild winters they may overwinter on grasses parthenogenetically. Large numbers on cereals can cause economic damage. Metopolophium dirhodum also transmit maize mosaic virus and barley yellow dwarf virus.

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Myzaphis rosarum (Lesser rose-aphid)

Wingless adults of Myzaphis rosarum are yellow-green to green. 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.

 

Alates have a dark central patch on the abdominal dorsum.

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.

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Longicaudus trirhodus (Rose -- columbine aphid)

Longicaudus trirhodus is a pale yellowish-green aphid with slightly darker green transverse bands across the abdomen. The third antennal segment is distinctly longer than the total length of the fourth and fifth antennal segments. The siphunculi are cone-shaped with dark tips and much shorter than the cauda. The cauda is long and finger-like much longer than its basal width. The body length of Longicaudus trirhodus apterae is 2.0-2.7 mm. The winged form has an irregular black mark on the abdomen.

 

The winged form (second picture above) has an irregular black mark on the abdomen.

The rose - columbine aphid host alternates from rose (Rosa spp.) in winter and spring to cultivated columbine (Aquilegia vulgaris) and meadow rue (Thalictrum) in the summer. Longicaudus trirhodus is found Europe, Asia and North America.

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Maculolachnus submacula (Rose-stem aphid)

Maculolachnus submacula apterae (see first picture below) are yellowish-brown, reddish-brown or dark chestnut brown. The dorsum has many fine hairs placed on small scleroites. Their dark brown antennae are about half the body length and the antennal terminal process is less than 0.25 times the length of the base of the sixth antennal segment. The legs of Maculolachnus submacula are dark brown, except for the bases of the femora and middle parts of tibiae. The hairs on the tibia are about half the diameter of the tibia. The siphuncular cones are dark and also have many hairs. The body length of Maculolachnus submacula is 2.7-3.8 mm.

 

Maculolachnus submacula feed on Rosa species (including roses). Much of the year they feed on stems near the ground, but in summer they move to the surface roots. Colonies are tended by ants which often tent over the aphids with soil particles. They do not host alternate. Oviparae and apterous males are found in September-October. Maculolachnus submacula are distributed throughout Europe eastward to Ukraine, Kazakhstan and India.

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Myzaphis bucktoni (Brown-lined rose aphid)

Adult Myzaphis bucktoni apterae are pale yellow to pale green with a dark brown head and dark brown dorsal markings. The markings consist of two large brown patches on the pronotum and paired brown stripes extending from the mesothorax to the base of the cauda converging between the siphunculi (see first picture below). Like other Myzaphis species, Myzaphis bucktoni is a small aphid: Their body length varies from 1.0-1.9 mm

 

Their alates have rather weak abdominal pigmentation which is usually divided intersegmentally in the midline, with large marginal sclerites on abdominal tergites 2-4 (see second picture above). The hairs on the front of the head are conspicuous. Antennae of Myzaphis bucktoni alates have 14-32 secondary rhinaria on the third antennal segment but none on the fourth.

This species mainly occurs on wild roses such as dog rose (Rosa canina) and harsh downy rose (Rosa tomentosa). Myzaphis bucktoni apterae feed dispersed along the mid-ribs of upper sides of the leaves. Sexual forms occur in November. Males are small, dark, wingless and very active. Oviparae are pale dusky olive green and have strongly swollen hind tibiae. Myzaphis bucktoni occurs throughout Europe, Asia and North America.

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Wahlgreniella nervata (Rose -- Strawberry-tree aphid)

Wahlgreniella nervata apterae are spindle-shaped and yellowish or green (see below first picture), sometimes mottled with reddish anteriorly (see below second picture). The femora do not have distinctly dark apices. Their siphunculi are slightly swollen rather symmetrically about their inner and outer faces, they have dark tips and a small flange. Winged viviparae of Wahlgreniella nervata have a green abdomen with variably developed dark dorsal cross-bands, sometimes coalescing into an irregular patch.

 

There are two subspecies:

  • Wahlgreniella nervata arbuti
    The apical segment of the rostrum is longer than 1.3 times the length of segment two of the hind tarsus. The live aphids are pale-yellowish to pale yellowish green. On Arbutus (strawberry tree) and Arctostaphylos (manzanitas and bearberries).
  • Wahlgreniella nervata nervata
    The apical segment of the rostrum is shorter than 1.3 times the length of segment two of the hind tarsus. The live aphids are dull greenish, sometimes with dark reddish mottling anteriorly. On rose (Rosa), but in culture able to live on Arbutus.

In North America Wahlgreniella nervata apparently host alternates between rose (Rosa) and ericaceous plants (mainly strawberry tree, Arbutus), although the host alternation has not yet been experimentally verified. Parthenogenetic populations on both Rosa and Arbutus have been introduced into Europe, and are treated as separate subspecies. Wahlgreniella nervata is considered an invasive species, having been reported from Damask rose in Turkey (Barjadze, 2011 ), and as a new pest of rose in India (Joshi et al., 2014 ).

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Sitobion fragariae (Blackberry -- grass aphid)

The Sitobion fragariae aptera is spindle-shaped and a dirty yellowish green, with small brown intersegmental sclerites on the abdominal dorsum. Their antennae are about the same length as the body, with the basal segments paler than the rest. The siphunculi are about twice as long as the pale pointed cauda and are usually entirely black, although they may have paler bases on the primary host. Compared to Macrosiphum funestum the siphunculi are shorter relative to the cauda (only 2 ×) and are darker or black. The body length of Sitobion fragariae apterae is 1.6-3.0 mm long.

 

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.

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Chaetosiphon fragaefolii (strawberry aphid)

Adult apterae of Chaetosiphon fragaefolii (see first picture below) are translucent yellowish white to pale greenish yellow. The head has spicules, and the antennae are 0.9-1.1 times the body length. The third antennal segment has 2-7 thick capitate hairs. The body is covered with conspicuous capitate hairs. The siphunculi are long and cylindrical and 2.2-3.3 times longer than the rather short cauda. The body length of Chaetosiphon fragaefolii apterae is only 0.9-1.8 mm.

 

The alate (see second picture above) has the head and thoracic lobes black and the abdomen pale greenish white with a brown-black dorsal patch. The alate body length is 1.3-1.8 mm.

Chaetosiphon fragaefolii feeds on strawberry (Fragaria spp.) especially the cultivated varieties. In Europe it is rarely found on wild strawberry (Fragaria vesca), but in America it is found on some wild species such as the Chilean strawberry (Fragaria chiloensis). Chaetosiphon fragaefolii usually occurs on new shoots, in the crown and close to the veins on the undersides of leaflets. The species mainly overwinters as parthenogenetic forms, although sexual forms have been produced in the laboratory.

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Damage caused by rose aphids

Most rose aphids feed on the young shoots where the damage can be quite considerable. The picture below shows the feeding damage caused by the common rose aphid (Macrosiphum rosae ) affecting the young leaves and developing flower buds.

Black sooty moulds may grow on the honeydew that aphids excrete, but this is not as much a feature of rose aphid infestations as with some other aphids. Of the different aphid species, the common rose aphid (Macrosiphum rosae, shown below) is usually the most damaging. Note the white egg laid by a hoverfly - this will hatch to give a larva which will feed on the rose aphids.

One reason that Macrosiphum rosae causes most damage is that it may remain on rose all year (albeit it has alternative summer hosts of teasel and valerian), whereas some other species (such as the rose -- grain aphid, Metopolophium dirhodum ) have only a brief sojourn on rose in spring. Other damaging species are the polyphagous potato aphid (Macrosiphum euphorbiae ) and especially the hairy rose aphid (Chaetosiphon tetrarhodum ). Numbers of the hairy rose aphid build up within shoot tips and buds (see picture below) where they are often overlooked until the damage is done.

Colonies of the very large Maculolachnus submacula  on old garden roses (see picture below) are such a rare and extraordinary sight (at least in Britain) that they should be conserved for their biodiversity value and regarded as a feature of the garden, rather than being sprayed to oblivion.

 

Control of rose aphids

  • For the gardener, physical removal of the aphids by brushing the stems or pinching the aphids may provide adequate control without the downsides of chemical control.

However, this can be a little challenging on very thorny roses such as Rosa rugosa. A better option (possibly the best for rose aphids) is to knock them off the plant using a jet of water from the garden hose. Aphids knocked off the plant in this way are usually so damaged that they are unable to continue feeding, or they may be eaten by ground-predators such as carab beetles. The advantage of this method is that most insect predators of aphids (see below on conserving natural enemies) are somewhat more resilient to this treatment, and will simply climb back on the plant to finish off the survivors.

  • A more common approach is to use chemical control.

The least harmful to the environment are the so-called 'organic' or 'natural' insecticides including pyrethrum (e.g. Py Spray Garden Insect Killer), plant oils (e.g. Vita Organic Pest & Disease Control) and fatty acids (insecticidal soaps, e.g. Doff Greenfly and Blackfly Killer). Whilst these are usually less harmful to the environment than synthetic insecticides, they will very likely still kill or repel aphid natural enemies so treated rose bushes are more prone to reinfestation.

Synthetic sprays include synthetic pyrethroids such as deltamethrin (e.g. Bayer Sprayday Greenfly Killer) and lambda-cyhalothrin (e.g. Westland Resolva Bug Killer). These are contact and broad spectrum insecticides with low mammalian toxicity which, unlike natural pyrethrum, remain active for several weeks.

The other main class of insecticides used in gardens is the neonicitinoid pesticides. These are systemic and broad spectrum and include thiacloprid (e.g. Bayer Provado Ultimate Bug Killer) and acetamiprid (e.g. Bug Clear Ultra, Rose Clear Ultra). Two other neonicitinoid pesticides (imidacloprid and thiamethoxam) have been withdrawn from use in Europe following concern over their effects on bees. Whether they will return to the market (or whether the remaining two will also be withdrawn) remains to be seen. For more details on chemical control of rose aphids see Royal Horticultural Society. 

  • Biological control involves the use of the natural enemies of the rose aphid to keep the number of aphids at a low level.

    There are several variants of this approach:

Predators or parasitoids can be reared in captivity and then repeatedly released in large numbers to consume the aphids. Such an approach is termed inundative releases, or augmentation. Markkula et al. (1979)  showed in Finland that inundative releases of Aphidoletes aphidimyza kept rose bushes free of aphids for the whole of the summer. Ferran et al. (1996)  released larvae of the coccinellids Harmonia axyridis into rose beds infested with Macrosiphum rosae in town squares in Paris. Aphid populations stabilized or decreased after predator release. Efficiency was comparable to that obtained using chemical treatments on neighbouring rose beds.

Initial attempts to use larvae of the coccinellids Coccinella septempunctata and Adalia bipunctata for controlling Macrosiphum rosae in small greenhouses were unsuccessful (Hamalainen et al., 1977 ) because the predators did not remain on the rose plants. Subsequent work focused more on using parasitic wasps. Aphidius ervi is currently considered effective for biological control of both Macrosiphum rosae and Macrosiphum euphorbiae (see Koppert Biological Systems ). Aphelinus abdominalis is also good, but needs a bit more warmth. Snyder et al. (2004)  showed that the predatory coccinellid Harmonia axyridis can complement aphid biocontrol by the parasitoid Aphelinus asychis, rather than disrupting it through intraguild predation. In other words, these predators seldom eat these parasitoids.

    • An alternative approach is termed 'classical biological control'.

This is where a pest's natural enemies are introduced to a new area where they do not occur naturally. The intention is that the natural enemies become established and maintain long-term sustainable control. Macrosiphum rosae was originally introduced to Australia without its natural enemies at the time of European settlement, and quickly became a major pest. In 1990 the specific parasitoid Aphidius rosae (see first picture below) from Europe was introduced into South Australia as part of a classical biological programme.

 

The parasitoid soon became established, and has since spread to at least New South Wales and the Australian Capital Territory, where parasitized mummies (see second picture above) are now common in spring. (Waterhouse & Sands, 2001 ) Aphids no longer reach the same damaging levels in spring and disappear earlier. However they may reappear in autumn.

    • Classical biological control is usually carried out by government authorities, but a third approach, sometimes termed conservation biological control, is much more widely applicable.

The aim is to conserve and encourage existing natural enemies in the environment. The best prospect for rose aphid control is probably to encourage oviposition by hoverflies (Syrphidae). Their larvae are voracious predators of rose aphids (see picture below). See also Aphids on rose with hoverfly larva  and Natskova (1973). 

Sadeghi & Gilbert (2000)  found that Macrosiphum rosae is a preferred host for two common predatory hoverflies, Episyrphus balteatus and Syrphus ribesii. Adult hoverflies need nectar for energy, and the protein from pollen for sexual maturation and egg development. Hickman & Wratten (1996)  found that planting blue tansy, a good source of nectar and pollen for hoverflies, alongside cereal crops enhanced the biological control of aphids by hoverfly larvae in cereal fields. However, there is no guarantee that predators will actually move from one plant to another. Frere et al. (2007)   found that rose bush (Rosa rugosa) strips did not influence the building up of aphid populations and of their natural enemies in adjacent cereal habitats.

Acknowledgements

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).

Useful weblinks 

References

  •  Barjadze, S. et al. (2014). Note on Wahlgreniella nervata (Gillette, 1908) (Hemiptera: Aphididae): a new pest of Damask rose in Turkey. Phytoparasitica 39 (3), 239-241. Abstract 

  •  Blackman, R.L. & Eastop, V.F. (1984). Aphids on the world's crops: an identification guide. J. Wiley & Sons, Chichester, UK.

  •  Ferran, A. et al. (1996). The use of Harmonia axyridis larvae (Coleoptera: Coccinellidae) against Macrosiphum rosae (Hemiptera: Sternorhyncha: Aphididae) on rose bushes. European Journal of Entomology 93, 59-67.Full text 

  •  Frere, I. et al. (2007). Apparent competition or apparent mutualism? An analysis of the influence of rose bush strip management on aphid population in wheat field. Journal of Applied Entomology 131(4), 275-283. Abstract 

  •  Hamalainen, M. (1977). Control of aphids on sweet peppers, chrysanthemums and roses in small greenhouses using the ladybeetles Coccinella septempunctata and Adalia bipunctata (Col., Coccinellidae). Annales Agriculturae Fenniae 16, 117-131. Full text 

  •  Hickman, J.M. & Wratten, S.D. (1996). Use of Phelia tanacetifolia strips to enhance biological control of aphids by hoverfly larvae in cereal fields. Journal of Economic Entomology 108(5), 832-840. Abstract 

  •  Joshi, S. et al. (2014). Wahlgreniella nervata (Hemiptera: Aphididae), a new pest of rose in India. Florida Entomologist 97 (1), 162-167. Full text 

  •  Markkula, M. et al. (1979). The aphid midge Aphidoletes aphidimyza (Diptera, Cecidomyiidae) and its use in biological control of aphids. Annales Entomologici Fennici 45(4), 89-98. Abstract 

  •  Natskova, V. (1973). The influence of parasitic and predacious insects on the rose aphid Macrosiphum rosae L. (Homoptera, Aphididae). Gradinarska i Lozarska Nauka 10(8), 115-122. Abstract 

  •  Sadeghi, H. & Gilbert, F. (2000). Oviposition preferences of aphidophagous hoverflies. Ecological Entomology 25(1), 91-100. Abstract 

  •  Snyder, W.E. et al. (2004). Complementary biocontrol of aphids by the ladybird beetle Harmonia axyridis and the parasitoid Aphelinus asychis on greenhouse roses. Biological Control 30(2), 229-235. Full text 

  •  Waterhouse, D.F. & Sands, D.P.A. (2001). Classical biological control of arthropods in Australia. CSIRO Entomology Canberra 2001. Full text