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Pemphigus bursarius

Poplar-lettuce gall aphid

On this page: Identification & Distribution 

Identification & Distribution:

In spring, Pemphigus bursarius form yellowish or reddish pouch-shaped galls (see picture below) on the petioles of the leaves of poplar. There may be more than one gall per petiole and the leaf lamina may curl and yellow.

Inside the gall the developing Pemphigus bursarius fundatrix is green with brown head and legs, wax covered and has no siphunculi. The 4-segmented antennae are about 0.12-0.15 times the length of the body.

The winged viviparae that emerge from these galls (shown live, and in alcohol, above) are greyish-green or greyish-brown with small siphuncular pores and are lightly covered with wax powder. Their antennae are 0.33-0.4 times the length of the body and have a distinct terminal process. There is brown shadowing around the wing veins.

Pemphigus bursarius host alternates between poplar and members of the daisy family Asteraceae, especially lettuce. In summer they live on the roots of the secondary host. The picture below shows a developing alate living on the roots of lettuce.

Pemphigus bursarius can be a serious pest of lettuce. Its distribution is almost cosmopolitan being found in Europe, western and central Asia, the Americas, northern and southern Africa and (possibly) Australia and New Zealand.

Acknowledgements

We have made provisional identifications from high resolution photos of living specimens, along with host plant identity. In the great majority of cases, identifications have been confirmed by microscopic examination of preserved specimens. We have used the keys and species accounts of Blackman & Eastop (1994)  and Blackman & Eastop (2006)  supplemented with Blackman (1974) , Stroyan (1977) , Stroyan (1984) , Blackman & Eastop (1984) , Heie (1980-1995) , Dixon & Thieme (2007)  and Blackman (2010) . We fully acknowledge these authors as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure  provided by Blackman & Eastop (2006).

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