Nasonovia ribisnigri Mosley Currantlettuce aphid

The currant/lettuce aphid is a widespread and generally common pest of Ribes, especially gooseberry; the aphids distort leaves at the tips of the shoots and, if bushes become heavily infested, infestations will also check growth. On lettuce, the pest feeds beneath the outer canopy of leaves and invaded plants quickly become contaminated by the aphids and their cast skins. Attacks on lettuce are of significance, therefore, even when the aphids are present in only small numbers. Direct damage to lettuce is particularly severe on protected crops.

BIOLOGY

This species usually overwinters in the egg stage on gooseberry and currant bushes. Colonies develop on these primary hosts in the spring. In late May or June, winged forms migrate to lettuce and certain other summer hosts, including various wild Asteraceae, e.g. Crepis, Hieracium and Veronica. Breeding continues on these summer hosts until the autumn, when there is a return migration to gooseberry and currant by winged females (gynoparae) and winged males. The former produce a generation of wingless females (oviparae) which, after mating with the winged males, deposit the winter eggs. In favourable situations, especially in glasshouses, aphids may survive on lettuce throughout the winter.

DESCRIPTION

Aptera 1.3-2.7 mm long, shiny dark green (summer form: often shiny pale yellow to green or reddish, with dark brown abdominal markings); antennae and legs long, with dusky tips; siphunculi moderately long, flanged, dark-tipped (in summer form: dark green or blackish); cauda elongate (Fig. 188f).

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