Food Plant: Allium porrum (Leeks), A.cepa (Onion), A.sativum (Garlic), A. schoenoprasum (Chives)

Mine: March-June: Sept-Nov

Notes: The female flies feed on the sap in the leaves and leave distinctive lines of feeding punctures as white dots. The white larvae initially make small mines in the leaf and then tunnel into it, which causes splitting of the leaf (as shown). Secondary bacterial and fungal infections often then follow. Orange brown puparia (3-4mm long) are formed towards the leaf bases. First discovered in Wolverhampton in 2002 and has spread in the UK since. In Europe it is considered a serious economic pest of Leeks and Alliums

Data: 30.i.2020, Wymondham, Norfolk, VC27

Image:© Graham Moates