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Eriosoma lanuginosum

Elm balloon-gall aphid

Identification & Distribution  Other aphids on the same host 

Identification & Distribution:

In spring Eriosoma lanuginosum fundatrices and their offspring develop in large, closed, bloated-leaf galls (see first picture below) near the ends of branches of various elm (Ulmus) species. This gall is produced by extreme enlargement of the cells of the leaf parenchyma on one side of the mid-rib near its base. The gall tissue is light green at first and covered with fine white hairs, becoming brown as the gall matures (see second picture below). Eriosoma lanuginosum fundatrices are blackish and wax powdered.

Images copyright Dr László Érsek, all rights reserved.

The fundatrigeniae are wax-powdered, apterous and yellowish when immature (see first picture below), but dark green with black legs when mature. Alates produced in the second and third generations on elm (see second picture below) are dark green to black and wax powdered. The body length of the adult Eriosoma lanuginosum alate is 2.1-3.1 mm. Apterae on the secondary hosts are pale yellow to reddish, with an adult body length of 2.0-2.7 mm.

Images copyright Dr László Érsek, all rights reserved.

The alates leave the galls on elm in late June-July and migrate to found colonies on fibrous rootlets of pear (Pyrus communis) or quince (Cydonia). The return migration to elm bark occurs in September. Eriosoma lanuginosum occurs throughout Europe, the Mediterranean area, and Asia east to Pakistan.


Other aphids on same host:

Blackman & Eastop list about 75 species of aphids  as feeding on elms worldwide, and provides formal identification keys for aphids on Ulmus.


We especially thank Dr László Érsek for the images shown above.

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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