. . . . . . . . . "Pemphigus bursarius" . . "Populus nigra" . . "Tig. 2016. Pemphigus bursarius forms gall on Populus nigra. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/3940011> on 05 Apr 2018." . . . . "http://iNaturalist.org is a place where you can record what you see in nature, meet other nature lovers, and learn about the natural world." .