Leaf-mine: The larva mines the leaves causing noticeable brown blotches, often many to one leaf. There is however, a similar-looking fungus which can cause confusion (UKMoths).

The mine begins at a flat, oval, somewhat iridescent egg shell at the upperside of the leaf. There starts an epidermal corridor of some mm, that abruptly widens into an upper-surface blotch. The blotch is elongate, often confined between by a pair of lateral veins; its colour is cinnamon, with a darker centre. The frass is not granular, like in Phyllonorycter species, but consists of a tarlike substance covering the floor of the mine. The number of mines can be as much as several tens per leaf. Pupation occurs within the mine (Bladmineerders van Europa).

The leaf-mine is also illustrated in British leafminers and the Encyclopedia of Life.

Watch the Naked Scientist video.

Larva: The larva is illustrated in Bladmineerders van Europa and the Encyclopedia of Life.

Pupa: The pupa and whitish silk cocoon are illustrated in British leafminers, UKMoths and the Encyclopedia of Life.

Adult: The adult is illustrated in UKMoths and the Encyclopedia of Life. The female genitalia, but not the male genitalia (check for update) are illustrated by the Lepidoptera Dissection Group.

Comments: The damage caused, impact on trees, management, hosts plants, monitoring, research and distribution maps are discussed in Forest Research.

A review of The Horse-chestnut Leaf-miner and its parasitoids has recently been published by Pocock, Evans, Straw and Polaszek, 2011.

Hosts in Britain:

Hosts elsewhere:

Time of year - larvae: May - October (British leafminers).

Time of year - adults: Multivolitine, with up to three generations a year (British leafminers).

Distribution in Great Britain and Ireland: This species was discovered near Macedonia in 1985, and since then has spread rapidly to other countries in Europe. It was first discovered in Britain at Wimbledon in south-west London in 2002, but possibly had arrived the previous year, as it was quite plentiful. It is thought that the species may be expanding partially due to accidental transportation by man, either by road or rail (UKMoths). Widespread in England and Wales including Bedfordshire, Berkshire, Brecon, Cambridgeshire, Cheshire, Derbyshire, East Norfolk, East Suffolk, East Sussex, Glamorgan, North Essex, North Hampshire, North Somerset, North Wiltshire, South Wiltshire, Stafford, Warwickshire, West Gloucestershire, West Norfolk, West Suffolk, West Sussex and Worcestershire (NBN Gateway - N.B. includes Watsonian Vice Counties having publicly available records that fall within or overlap the vice county border at 10km resolution or better i.e. a record for a vice county may relate to an adjacent vice county - for included datasets see NBN Grid map below). See also Forest Research distribution maps for details of range expansion 2002-7 and British leafminers distribution map). Also recorded in the Channel Is. (Guernsey) (British leafminers - Newsletter).

NBN Grid map: Note that not all datasets on the NBN Gateway may be available on the map below. If you are an NBN Gateway registered user you can request access for missing datasets via the link 'Open interactive map in new window' below.

Distribution elsewhere: Widespread in continental Europe including Albania, Austria, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Danish mainland, French mainland, Germany, Greek mainland, Hungary, Italian mainland, Liechtenstein, Luxembourg, Macedonia, Poland, Romania, Slovakia, Slovenia, Spanish mainland, Sweden, Switzerland, The Netherlands, Ukraine and Yugoslavia (Karsholt and van Nieukerken in Fauna Europaea). Also recorded in North America (Forest Research).

NBN interactive distribution map(s) of known host species in Great Britain and Ireland and elsewhere:

Parasitoids in Britain and elsewhere: