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Currant-yellow rattle aphid, Northern currant aphidIdentification & Distribution Biology & Ecology Damage & Control
Identification & Distribution:Adult apterae of Hyperomyzus rhinanthi are yellowish-green, green or dark green with extensive shiny black dorsal sclerotization. There is a large ovoid black central patch on the abdominal dorsum, cross bars on the other tergites, and postsiphuncular and marginal sclerites. Their antennae and legs are black except at their bases. The first tarsal segments all have 4 hairs (distinguishes Hyperomyzus rhinanthi from Hyperomyzus hieracii, where first tarsal segments have 3 hairs). The siphunculi are black and are 1.6-2.0 times longer than the rather thick cauda. The diameter of the swollen part of the siphunculi is 1.6-2.4 times the diameter of its basal part.
Hyperomyzus rhinanthi alates are dark green with the sclerotized parts black. Winged migrants in spring have 36-48 secondary rhinaria on the third antennal segment, 12-22 on the fourth, and 0-3 on the fifth. Winged migrants in autumn have 65-95 secondary rhinaria on the third antennal segment, 12-24 on the fourth, and 0-6 on the fifth.
Hyperomyzus rhinanthi host alternates from red currant (Ribes rubrum) in spring to yellow rattle (Rhinanthus major) and eyebrights (Euphrasia spp.) in summer. Oviparae and alate males develop in autumn. The species is found throughout Britain, but is reputedly more common in the north than the south. Hyperomyzus rhinanthi is widely distributed in Europe.
Biology & Ecology:
One unusual characteristic of Hyperomyzus rhinanthi is that on yellow rattle the aphids feed on the inner side of the calyces of the flower (see second picture above). Hence to find this aphid, one must open the flowers. In Britain we have found Hyperomyzus rhinanthi inside yellow rattle flowers at Cissbury Ring in West Sussex, and at Dundreggan in Scotland.
The species seems to be more often found on its secondary host than on its primary host. Heie, 2009 notes that he has often seen it in Denmark on its secondary host Rhinanthus, but only in Iceland has he seen it on the primary host Ribes alpinum.
Both times we have found this aphid it has been living in mixed species populations inside the flower with leaf-curling plum aphid, Brachycaudus helichrysi, as shown below.
Damage and control
Hyperomyzus rhinanthi is a well established minor pest of red currant in Iceland. Spring infestations on young shoots and suckers can cause leaf curl.