Dichotomous table for leafminers
1a at the start of the mine, at the leaf underside, a group of about 5 elliptic egg shells: Pegomya sp. *
1b no egg shells visible => 2
1c galls, etc => Tables for all parasites per species
2a irregular corridor or blotch, usually with a round hole at either end; often several mines in a leaf; older larvae live free, causing window feeding: Hypera rumicis
2b blotch, without holes; larva remains in the mine till shortly before pupation: Mantura rustica
* Hering (1957a) and Robbins (1991a) report finds of Pegomya-larvae on this plant. The larvae have not been reared, and are not identified. Hering assumes that it concerns one of the species living on Rumex, that has tried to step over to Rheum. A photo by Rob Edmunds of such a mine demonstrates that these attempts are not succesfull: the mine remains corridor-like, and is therefore atypical.