Pemphigus borealis Tullgren, 1909

on Populus, primary host plant

gall

red or green globular purse gall at the base of a still green shoot. The gall is so strongly curved that the broad, apical opening almost touches the base. The gall is maximally 2.5 cm large, and often occurs in fused groups of 4-6.

host plants

Salicaceae, monophagous

Populus balsamifera, x berolinensis, laurifolia, nigra, suaveolens.

on Bidens, secondary host plant

gall

aphids at the roots.

host plants

Asteraceae, monophagous

Bidens cernuus, tripartitus.

references

Bellmann (2012a), Blackman & Eastop (2014), Buhr (1965a), Dauphin & Aniotsbehere (1997a), Heie (1980a), Kollár (2011a), Lampel & Meier (2003a), Ludwig (1974a), Osiadacz & Halaj (2014a), Osiadacz & Wojciechowski (2008a), Redfern & Shirley (2011a), Tomasi (2014a).