The larvae of the sawfly Fenusa ulmi produce full depth blotch mines on the leaves of Elm species. The mines usually start from the angle formed by the midrib and a vein. The final mine may occupy a sizable part of the leaf. Frass in black grains, initially often in long pearl chains, in older mines in loose grains. The mines are recorded more frequently than the adults, which are rather plain, black sawflies.
Where Elm species are present.
The mines occur from early summer once Elm is in leaf.
Widespread in Britain but not well recorded.
Uncommon or under recorded in Leicestershire and Rutland. It is believed that the Claybrooke Magna record of 2nd June 2016 is the first for our area (VC55).
Leicestershire & Rutland Map
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Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015