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How to Get Rid of Rose AphidsControl and IdentificationOn this page: Physical removal Conservation biological control Inundative releases Classical biological control Chemical control Which aphids damage roses Why identify rose aphids UK rose aphidsPhysical removal or destructionWhen you see a few aphids on your prized roses, most gardeners' first instinct is to simply squash them - or at least to brush them off. If you have been lucky enough to spot the first invaders, and if you clobber them every day through the season, then this approach may provide adequate, if rather time-consuming, control. However, this can be a little challenging on very thorny roses such as Rosa rugosa. A better option is to knock them off the plant using a high pressure jet of water. For large thorny rose bushes this is sometimes the best approach, without the downsides of chemical control. You could use a garden hose or, more effectively, you can fit a high pressure spray device known as a 'water wand'. 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 carabid beetles. A further 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 up the plant to dine on the survivors. Biological controlRather than trying to remove the aphids yourself, it makes more sense to 'recruit' the natural enemies of rose aphids to help you in the task. Remember the objective of this approach is not to get rid of every last aphid, it is simply to keep them at a sufficiently low level such they don't damage the plants or disfigure their appearance. There are several variants of this approach:
Chemical controlNow we come to chemical control under which we include both 'organic' and synthetic chemicals. The least harmful insecticides 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). These are less harmful to the environment than synthetic insecticides, and we would recommend them if other methods are not appropriate or viable. But they will very likely still repel (and sometimes kill) aphid natural enemies, so treated rose bushes are more prone to reinfestation. The other approach is to use synthetic insecticides of which two types may be available to the gardener. The first is the 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. But they will also kill the natural enemies of rose aphids, so we cannot recommend these for gardeners. 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. Some of the neonicitinoids may have fewer effects on some natural enemies, but we would still advise against their use. For more details on chemical control of rose aphids see Royal Horticultural Society. Which aphids damage roses?About thirty species of aphids feed on cultivated roses worldwide, of which twelve are known in Britain. Of the different aphid species, the common rose aphid (Macrosiphum rosae) is usually the most abundant. They are green or pink with long black siphunculi. The picture below shows a large colony of the common rose aphid. The white egg in the picture was laid by a hoverfly - this will hatch to give a larva which will feed on the rose aphids.
The common rose aphid is the most damaging not only because it is the most abundant species, but also because it feeds on the young shoots. The young shoots and developing flower buds become twisted and contorted as a result of the digestive action of the saliva injected (see picture below).
Another reason that Macrosiphum rosae causes most damage is that it may remain on rose all year (albeit some winged forms may migrate to their alternative, summer, hosts of teasel and valerian). Some other species, such as the rose-grain aphid, (Metopolophium dirhodum, note the pale siphunculi in the picture below) have only a brief sojourn on rose in spring. Hence it is fairly pointless attempt to control this species - all the young ones will develop wings and leave of their own accord to colonize grasses!
But ignore some of the other species at your peril! After the common rose aphid, the hairy rose aphid (Chaetosiphon tetrarhodum) is probably the most harmful, and is especially common on rugosa roses. Numbers of this very small aphid build up within shoot tips and on buds (see picture below) where they are often overlooked until the damage is done.
We should also mention the largest aphid species on rose, the giant rose stem aphid Maculolachnus submacula (see picture below). This is very rare, only occurs on old garden roses and is attended by ants. They are such an 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. They are unlikely to be numerous enough to cause any damage to the rose.
Identifying rose aphidsAbsolutely any species of aphid might accidentally land upon a rose plant, but very few species are adapted to survive on roses. The vast majority of accidental arrivals die out quite quickly. 'Rose aphids' are therefore defined as those species which are known to produce viable colonies. The genus Rosa contains perhaps a hundred species, plus hybrids thereof - we will only focus on the cultivated varieties of 'garden' roses. Blackman & Eastop (1984) list 32 species of aphid as feeding on cultivated 'roses' worldwide (Show World list), and provide formal identification keys. That list excludes aphids found on rose species not normally cultivated. It also excludes species of aphids that accidentally find themselves on a rose but fail to produce a viable colony (otherwise there could be, potentially, more than 5000 species of 'rose aphids'). Of those 32 aphid species, Baker (2015) lists 12 as occurring in Britain (Show British list).
The 11 species below are those we have found ourselves, listed in rough order of abundance on rose. In Britain, and the rest of northern Europe, Rhodobium porosum is only found on roses in glasshouses. Rose aphid speciesMacrosiphum 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. 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. 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. 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. 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.
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. 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. 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 cultivated 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. 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. 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:
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). 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. 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, and occasionally on rose (Rosa). 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. Postscript - an extremely rare aphid on garden rosesYou may have noticed that we have not mentioned what is possibly the aphid most noticed in gardens - "the black bean aphid" (Aphis fabae). This aphid is a notoriously polyphagous species, found in abundance on broad beans and many other garden plants. Aphis fabae has been recorded on dog rose (Rosa canina) but until recently had never been recorded on cultivated roses. Nevertheless, we have observed one very small colony of rather sick-looking black bean aphids (shown below) on cultivated rugose rose (Rosa rugosa). The adult in the picture was shrunken and probably unable to reproduce. To our knowledge, this is the first and only record of such, and supports the conclusion that, on cultivated roses, unlike beans, Aphis fabae is a very rare aphid (see our page on rare aphids), albeit this aphid certainly not require any conservation efforts!
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