Rheum, rhubarb

fam. Polygonacea

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 => 100

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

100a Nematoda => 101

100b Acari => 102

100c Coleoptera => 103

100e Diptera => 104

100f Hemiptera => 105

100d Hymenoptera => 106

100g rust fungi => 107

100h smut fungi => 108

100i powdery and downy mildews => 109

100j other causers => 110

101 – Nematoda

101a Anguinidae: Ditylenchus dipsaci

105 – Hemiptera

105a Aphididae: Aphis acetosae

107 – rust fungi

107a Pucciniaceae: Puccinia phragmitis, rhei-undulati

108 – smut fungi

108a Glomosporiaceae: Thecaphora schwarzmaniana

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe polygoni

109b Peronosporaceae: Peronospora jaapiana

110 – andere veroorzakers

110a Fungi, Mycosphaerellaceae: Ramularia rhei

* 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.

08/12/2016