Sowthistle Aphid
Hyperomyzus lactucae (Linnaeus)

Hosts

Primarily on blackcurrant, Ribes spp, and sowthistle, Sonchus oleraceus. This species is commonly found feeding on lettuce but will not colonise this host.

Distribution

Widespread in most areas of the world except Africa.

Economic importance

The primary vector of lettuce necrotic yellows in Australia. Control of sowthistles near lettuce crops provides adequate control.

Identification

A medium sized, dark coloured aphid with distinctively swollen siphunculi. The only other aphid on lettuce with clavate siphunculi is the uncommon Myzus cymbalariae which has the antennal tubercles converging anteriorly while the sowthistle aphid has the antennal tubercles well developed but diverging anteriorly.