Plant Parasites of Europe

leafminers, galls and fungi

Fenusa pumila

Fenusa pumila Leach, 1817

Fenusa pumila: mines on Betula pendula

Betula pendula, Hungary, Kimle, 30.v.2019 © László Érsek

Fenusa pumila: mines on Betula pendula

same leaf, underside: the sponge parenchyma is almost wholly untouched,

Fenusa pumila: larva

larva in opened mine

Fenusa pumila: larva

larva dorsal and ventral

Fenusa pumila: larva

head and thorax dorsal

Fenusa pumila: larva

head and thorax ventral

Fenusa pumila: larva

head and thorax lateral


Betula pubescens, Hilversum


Betula pubescens, Nunspeet: young mines


Betula pendula, Millingerwaard: oviposition scar


Rather large, clear, partly full depth blotch that begins in the axil of a thick lateral vein. Often the oviposition leaves a greyish-green scar (photo). Generally several mines in a leaf. The mine expands within the confines of the midrib and two lateral veins; only close to the leaf margin, where the lateral veins are thin, the mine may trespass over a vein.

host plants

Betulaceae, oligophagous

Alnus viridis; Betula caerulea, pendula, pubescens.

Strong preference for the younger leaves; mines of the later generations therefore at the end of the twigs (Friend, 1931a; Lindquist, 1959a; Cheng & LeRoux, 1965a).


Mines between June and September, in 2-3 generations (Lindquist, 1959a; Cheng & LeRoux, 1965a).


BE recorded (Fauna Europaea, 2008).

NE recorded (van Ooststroom, 1976a).

LUX recorded (Chevin, Ellis & Schneider, 2011a).

distribution within Europe

Entire Europe, with possible exception of the Balkan Peninsula (Fauna Europaea, 2008).



Fenusa pusilla auctorum.

parasitoids, predators

Chrysocharis amyite.


When (as is usual) several mines occur in a leaf, they often develop at quite different speeds. The difference sometimes is quite considerable: sometimes several larvae are full-grown and about to leave their mine, while others seem to have just emerged from the egg. It is not certain (albeit probable) that all mines in a leaf stem from a single ovipositing female. The biological meaning of this differential development is not clear.

Young mines may be confused with mines of Incurvaria pectinea that have not yet made their excisions. The presence of greyish green discoloured oviposition scars then characterizes F. pumila (Buhr, 1941a).

In Europe F. pumila is practically harmless. However, the species has unintentionally been introduced into the United States, and has developed there into a serious forestry pest (Eichhorn & Pschorn-Walcher, 1973a; Smith, 1987a).

Contrary to Fenusella nana, this species mines the youngest, only partly unfolded leaves in the periphery of the crown (DeClerck & Shorthouse, 1985a).


Ahr (1966a), Altenhofer (2003a), Altenhofer, Hellrigl & Mörl (2001a), Beiger (1979a), Beneš & Holuša (2015a), Blank ao (1998a), Buhr (1941a, 1964a), Çalmaşur & Özbek (2004b), Cheng & LeRoux (1965a), Chevin, Ellis & Schneider (2011a), DeClerck & Shorthouse (1985a), Digweed, MacQuarrie, Langor ao (2009a), Eichhorn & Pschorn-Walcher (1973a), van Frankenhuyzen & Houtman (1972a), van Frankenhuyzen Houtman & Kabos (1982a), Friend (1931a), Haase (1942a), Hering (1927b, 1937c, 1956a), Huber (1969a), Kirichenko, Augustin & Kenis (2018a), Kozlov, van Nieukerken, Zverev & Zvereva (2013a), Kruse, Smith & Schiff (2010a), Kvičala (1938a), Lengesova (2008a), Lindquist (1959a), Liston (1993b, 1995b), Lorenz & Kraus (1957a), Maček (1999a), Michalska (1972a, 1976a), Nowakowski (1954a), van Ooststroom (1976a), Pieronek (1962a), Pieronek & Soltyk (1993a), Pschorn-Walcher & Altenhofer (2000a), Pschorn-Walcher & Taeger (1995), Ripper (1931a), Robbins (1991a), Savina & Chevin (2012a), Scobiola-Palade (1974a), Skala (1951a), Skala & Zavřel (1945a), Smith (1971a, 1987a), Sønderup (1949a), Stammer (2016a), Taeger, Blank & Liston (2006a), Taeger ao (1998a), Viramo (1969a), Wahlgren (1944a, 1951a, 1963a), Zoerner (1969a, 1970a), Zwakhals & Blommers (2022a).

Last modified