Aphidend
General
The large blackberry aphid, Amphorophora rubi, is very similar to the large raspberry aphid Amphorophora idaei. As both aphid species are host specific the host plant is the simplest method to distinguish these two species. The large blackberry aphid is widely distributed in Europe and also established in New Zealand. It only feeds on cultivated and wild blackberries.
Life cycle and appearance of Large blackberry 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 large blackberry aphid are 2.6-4.1 mm long, pale to yellowish green with long antennae, legs and siphunculi. The cauda is short and triangular.
The aphids overwinter as eggs on blackberry plants. After emerging in spring, the aphids mainly feed on the underside of leaves and start to reproduce parthenogenetically. They are very mobile and drop from the plant when they are disturbed. Winged aphids usually appear in June and July and migrate to new canes or host plants where they produce wingless aphids again. In October to December winged aphids appear again. These lay the winter eggs.
Damage symptoms
High populations of large blackberry aphids can reduce yield.