A seldom recorded leaf-mining sawfly, with only about 16 records to date, mostly in England from Yorkshire southwards with one record in southern Scotland (Musgrove, 2023).
Antennae with 10 segments, or with a very long ninth more than 1.5 times as long as the eighth. Pronotum yellow and mesopleura marked with yellow. Labrum, clypeus and base of mandibles more or less white. The abdomen is piceous with pale apical margins on tergites and sternites. In the female the hind femur is yellow ventrally.
Fenusella hortulana larvae feed in mines in the leaves of black poplar. In some countries, infestations can be severe with densities of up to 12 larvae per leaf. Elsewhere population density is low with single larval mines in isolated leaves. It may be that differing predator species play a role in different regions. It should be noted that Fenusella glaucopis may sometimes lay on black poplar and the mines are similar. Larvae need to be examined or reared through.
Size: Approx. 4 - 6mm
GB IUCN Status: Endangered
GB Rarity Status: Nationally Scarce
Distribution: England, Scotland, Ireland
Flight period: May to June
Plant associations: Populus nigra (black poplar)
Altenhofer, E. 1980: Zur Systematik und Morphologie der in Baumblättern minierenden Blattwespen (Hym., Tenthredinidae). - Zeitschrift für angewandte Entomologie, Hamburg, Berlin 89(1): 42-53.
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168. https://doi.org/10.3897/BDJ.2.e1168
Lotfalizadeh, H., Shiri, T. and Liston, A., 2017. Poplar tree blotch leaf-miner, Fenusella hortulana (Klug)(Hymenoptera: Tenthredinidae), a pest of Populus in Iran with review of its geographical distribution. Journal of Insect Biodiversity and Systematics, 3(3), pp.273-279.
Musgrove, A.J. 2023. A review of the status of sawflies of Great Britain - Phase 2: The Athaliidae and the Tenthredinidae (excluding Nematinae). Natural England, unpublished