Plant Parasites of Europe

leafminers, galls and fungi

Isochnus sequensi

Isochnus sequensi (Stierlin, 1894)

on Populus, Salix

Isochnus sequensi: mines on Populus x canadensis

Populus x canadensis, Russia, Moscow region, Zhukovo village, 18.vii.2021 © Andrey Ponomarev

Isochnus sequensi: larva

larva in opened gall

Isochnus sequensi: mines on Populus x canadensis

30.vii.2021, another leaf

Isochnus sequensi: larva

larva dorsal,

Isochnus sequensi: larva


Isochnus sequensi: larva



Salix dasyclados, Cadzand, 21.x.2004


Salix alba, Brummen, 11.x.2007: upper epidermis coloured like leather; all frass as a tar-like film on the floor of the mine


Almost round, brown to brownish black, upper surface, very opaque blotch, about 1 cm in diameter, without an initial corridor. Upper epidermis leathery in colour. Often several mines in a leaf. All frass as a tar-like film on the floor of the mine. Egg shell at leaf underside, difficult to see, hyaline. Larva solitary. Pupation in the mine; pupa not in a cocoon.

host plants

Salicaceae, oligophagous

Populus balsamifera, x canadensis, nigra; Salix alba, babylonica, caprea, cinerea, daphnoides, x fragilis, gmelinii, pentandra, purpurea, triandra, viminalis.

Salix is the main host plant genus.


Larven in August-October (Hering, 1957a). The larvae pupate in September; soon after the adults emerge (Rheinheimer & Hassler, 2010a).

BE in 2008 bred from Salix by Jorgen Ravoet; det. Theodoor Heijerman; see also (2010).

NE recorded (van Frankenhuyzen & Freriks, 1986a; Heijerman, 1993a).

LUX not recorded (Fauna Europaea, 2007).

distribution within Europe

From Scandinavia, the UK and France to Bulgaria and Romania (Fauna Europaea, 2007).




Rhynchaenus, Isochnus populicola Silfverberg, 1977; Orchestes, Rhynchaenus populi (Fabricius, 1792).


Hering (1957a) describes the species as very common and numerous; this is not generally true in the Netherlands, although it may suddenly be locally abundant on pollard willows (van Frankenhuyzen & Freriks, 1986a).


Buhr (1933a, 1964a), Caillol (1954a), Csóka (2003a), Delbol (2013a), van Frankenhuyzen & Freriks (1986a), van Frankenhuyzen & Houtman (1972a), van Frankenhuyzen Houtman & Kabos (1982a), Haase (1942a), Heijerman (1993a), Heijerman & van der Leij (1997a), Hering (1930a, 1957a), Huber (1969a), Kirichenko, Augustin & Kenis (2018a), Kleine (1924a/1925a), Kvičala (1938a), Maček (1999a), le Monnier (2003a), Nowakowski (1954a), Rheinheimer & Hassler (2010a), Roques, Cleary, Matsiakh & Eschem (2017a), Skala & Zavřel (1945a), Sønderup (1949a), Stammer (2016a), Starý (1930a), Trägårdh (1910a), Vidal (1988a), Vorst (2010a), Yates & Hodge (2000a), Yunakov, Nazarenko, Filimonov & Volovnik (2018a), Zlobin (1986b), Zoerner (1969a, 1970a).

Last modified 19.xii.2021