Last modified: April 10, 2021, 11:35 a.m.
A native species to North America and accidentally introduced to Europe and first recorded near Basel, Zwitserland in 1983. In Belgium recorded for the first time in 2001 in LI. Expands rapidly throughout the country. Hitherto a fairly common species.
Naturalised In Belgium since September 2001.
This invasive species has a North-American origin where it is widespread. It was accidentally introduced into Switzerland (Basel) in 1983 and from there spread over Central Europe. It was first found in The Netherlands in 2000 (province of South-Limburg) and probably invaded Belgium from those populations. It has spread all over Belgium since then, except for LX (2018).
De first instar lives in a very short gallery at the underside of a leaf and widens this into a circular, or oval white blotch. This blotch never crosses the main vein of the leaf. On the upperside of the leaf, the blotch is visible as an oval patch with a different shade of green than the rest of the leaf.
See also gracillariidae.net and bladmineerders.be.
Typical for this species is that several larvae can occur in the same blotch. Though they start their mining life individually, their blotch mines might sometimes touch and merge and then the caterpillars live and pupate in the same large blotch.
The adults hatch in late autumn and hibernate.
The adults fly in three generations a year, which are indistinguishable: from May till October.
The larva is monophagous on Robinia pseudoacacia.
Parks, street plantations with Robinia pseudoacacia, an invasive plant itself.