Syrphidae
Hoverflies- Kind
- Wild — attract it
- Best for
- Outdoors — attract, don't buy
Pest
Rose aphid
Macrosiphum rosae
The short answer
A large aphid, 1.7–3.6 mm long, in green or pink to red-brown forms, with long black cornicles and a pale yellow tail. It crowds onto rose buds and shoot tips in spring, leaving honeydew and cast white skins. In most of California UC IPM calls it a problem for about six weeks in spring and early summer, before heat and predators bring numbers down — which is why most gardens need no spray at all.
hero macro · green and pink forms on a rose bud
Wingless adults and nymphs of Macrosiphum rosae, green and pink forms, on a rose bud. Photo: pending.
Identification
Wingless adults are 1.7–3.6 mm, larger than most garden aphids, in two colour forms: green, or deep pink to red-brown, often together on one bud. The antennae are dark. The best tell is at the rear: long black cornicles that curve slightly outward, and a pale yellow cauda between them. The RHS gives 2–3.5 mm as the common size.
Three aphids are common on roses (UC IPM): rose aphid, potato aphid and cotton aphid. Potato aphid is similar in size and also green or pink but has pale cornicles; cotton (melon) aphid is much smaller, 1–2 mm, with short black cornicles. Winged rose aphids have conspicuous black patches along the sides of the abdomen.
Easily confused with
- Potato aphidAlso a pestLook at the cornicles. Potato aphid's are pale, at most with darker tips; rose aphid's are entirely black, and its tail is pale yellow.
- Melon (cotton) aphidAlso a pestMelon aphid is smaller, about 1/25–1/12 in (1–2 mm), with short, stout black cornicles. Rose aphid is larger, 1.7–3.6 mm, with long black cornicles.
- Aphid mummiesBeneficial — leave itA parasitised aphid swells into a crusty, golden-brown mummy, later with a round exit hole where the wasp left. Leave mummies on the plant: they mean parasitoids are working.
- Hoverfly larvaeBeneficial — leave itHoverfly larvae are legless and maggot-like, tapering to a point at the head end, 1/5–4/5 in (5–20 mm) long. Aphids have legs and a pair of cornicles.
Damage symptoms
UC IPM is plain about it: low to moderate numbers do little harm to roses. As colonies grow, honeydew coats the leaves and turns black with sooty mould, and very heavy populations distort or kill buds and shrink the flowers. The aphids favour rapidly growing tissue, so the damage is at the buds and tips, not the older leaves.
- Buds and shoot tips coated in green or pink aphids
- White cast skins on buds and young leaves
- Sticky honeydew, then black sooty mould
- Distorted buds, or buds that die before opening, under heavy infestation
- Smaller flowers on heavily infested stems
- Ants tending the colonies
Lifecycle & degree days
Rose aphid usually overwinters as eggs on rose stems, although in mild winters it can keep breeding. In spring the colonies build on the new growth, females bearing live young without mating. They also produce large numbers of winged adults, most of which move to secondary hosts such as teasel and valerian, though colonies can be found on roses all summer. Heat works against it: at 28 °C (82 °F) reproduction and lifespan both shorten.
- Winter
- Eggs on rose stems; active in mild winters
- Generation time
- 10–14.8 days at 25 °C, by rose cultivar
- Offspring / female
- 9.2–38.7, by rose cultivar (lab)
- Heat
- Reproduction and lifespan fall at 28 °C (82 °F)
- Problem window
- About 6 weeks, spring to early summer (California)
J
F
M
A
M
J
J
A
S
O
N
D
Host crops
Mostly roses and their relatives: USDA's AphID notes it feeds mostly on rosaceous plants, with records from 15 other plant families, and it is globally distributed apart from eastern Asia. In spring most winged forms move to secondary hosts such as teasel and valerian. Rose cultivars differ: in one lab study, offspring per female ranged from 9.2 on 'Tea' to 38.7 on 'Orange Juice'.
Monitoring & action thresholds
Action threshold
None set
UC IPM gives no number for garden roses; it says low to moderate numbers cause little injury and that broadly toxic insecticides are rarely justified. Act when buds are coated and no mummies or predator larvae are in the colonies — and even then, water or soap first.
Check new shoots and buds at least twice a week while roses are growing fast in spring. Look for mummies (bloated, crusty bronze or black parasitised aphids) and for hoverfly, lacewing and ladybird larvae among the colonies: UC IPM expects numbers to drop substantially within a week or two once mummies appear. Ants on the canes mean something is protecting the aphids.
Beneficial
Biological control
Rose aphid is a garden problem that natural enemies usually solve. UC IPM names parasitic wasps, lady beetles (especially the convergent lady beetle), soldier beetles, syrphid fly larvae and green lacewings; ants protecting the colonies are the main thing that stops them. The parasitoid Aphidius rosae hunts aphids in rose bushes and arrives on its own. No supplier we checked names rose aphid as a target for a parasitoid: Aphidius colemani is released against small aphids, and A. ervi is sold for larger ones such as potato aphid. Wild lacewings help, but UC IPM notes that releasing green lacewings against rose aphid has not given significant control in research trials, and bought convergent lady beetles mostly fly away. Under glass, the gall midge is sold against all aphid species.
Hippodamia convergens and others
Ladybugs- Kind
- Wild — attract it
- Best for
- Outdoors — conserve the ones already there
Aphidoletes aphidimyza
Aphid predatory midge- Rate
- 1–10 /m² per release, weekly
- Temp
- 20–26 °C best; needs warm nights and long days
- Best for
- Colonies under glass
Cultural controls
UC IPM's garden approach: knock them off, keep ants away, and leave the rest to predators and the summer heat.
- Hose colonies off with a forceful stream of water early in the day
- Squash colonies on buds between finger and thumb
- Keep ants off the canes with sticky barriers or baits
- Avoid heavy nitrogen feeding, which drives soft new growth
- Grow open flowers nearby to feed hoverflies and parasitoid wasps
Chemical, last resort
Broad-spectrum sprays are rarely justified on garden roses — they kill the predators that end the outbreak. Soil-applied imidacloprid is rarely needed and may harm bees and natural enemies; never let sprays drift onto open flowersCheck any product before it goes on. Open the compatibility matrix →
- Insecticidal soapREI 12 h
- Narrow-range oilREI 4 h
- Neem oilREI 4 h
- Imidacloprid (soil-applied)REI 12 h
Rating: the effect on this pest's natural enemies if a spray hits them or they feed on treated plants. REI is the re-entry interval on farm and greenhouse labels; home labels usually give none, so follow the label.
Sources
UC IPM Pest Notes: Roses: Insects and Mites, UC ANR Pub. 7466 (Flint & Karlik; updated 10/2019)
UC IPM Pest Notes: Aphids, UC ANR Pub. 7404 (M.L. Flint; updated 07/2013)
UC IPM Floriculture & Nurseries Guidelines, Pub. 3392: Aphids treatment table (updated 01/2022)
UC IPM, Relative Toxicities of Pesticides Used in Floriculture to Natural Enemies (updated 01/2022)
RHS Advice: Rose aphids (accessed Sept 2026)
USDA AphID: Macrosiphum rosae (Dvořák & Jensen; v1.3, 2014)
InfluentialPoints: Macrosiphum rosae, rose aphid (accessed Sept 2026)
Golizadeh et al. 2017, Neotrop. Entomol. 46: 100–106 (rose cultivar life tables)
Dampc et al. 2021, Biology 10: 480 (M. rosae at 20, 25 and 28 °C)
Völkl 1994, Oecologia 100: 177–183 (Aphidius rosae in rose bushes)
UC IPM Natural Enemies Gallery: Syrphids
Koppert: Ervipar (Aphidius ervi) and Aphidend (Aphidoletes aphidimyza) product pages
UConn IPM: Biological Control of Aphids (Pundt)
Page status
Drafted from the sources below, then checked claim by claim against those sources on 23 September 2026.
Suggest a correction →Rose aphid by crop
The same pest behaves differently on different hosts. Each page below gives the host-specific control, rate and threshold.