The rose aphid, Macrosiphum rosae, is a serious and often abundant pest of roses. It is virtually cosmopolitan and widely spread in Europe.
Life cycle and appearance of Rose aphid
Aphids have a complex life cycle, with both winged and wingless forms of adults and a great variety in colour. In greenhouses, reproduction takes place by parthenogenesis, with unfertilized viviparous females continuing to produce new generations of females. Aphids moult four times before reaching adulthood. With each moult they shed white skin, betraying their presence in the crop.
Wingless females of the rose aphid are 1.7-3.6 mm long and green or deep pink to red-brown. The antennae and sometimes the head is dark in colour. The siphunculi are black and bent outwards.
The rose aphid usually overwinters on rose bushes in the egg stage, although in mild winter some adults may continue to reproduce parthenogenetically.
Large colonies of aphids can build up on roses in spring and summer; sometimes shoots are completely covered by aphids. In summer, winged aphids spread the infestation to other rose plants and sometimes also to secondary hosts. Colonies are often present on rose bushes throughout autumn until their development is hampered by cold weather. In heated greenhouses they can be present year-round.
Infestations with rose aphids retard the growth of buds and new shoots. Foliage and flowers are often disfigured and contaminated with sticky honeydew on which black sooty moulds develop.