Persicaria, knotweed

The classical genus Polygonum has been split into Fallopia (incl. Reynoutria), Persicaria (incl. Bistorta), and Polygonum.

1a small, brown, tentiform mine: Calybites phasianipennella

1b corridor: Chromatomyia horticola

1c blotch, may be preceded by a corridor => 2

1d galls, etc => 100

2a large blotch, not preceded by a corridor; larvae communal; at the start of the mine mostly a group of some elongated egg shells => 3

2b blotch preceded by a narrow corridor; larva solitary; no egg shell visible: Agromyza polygoni

3a larva: mandible with some fine teeth: Pegomya bicolor

3b mandible with ± 3 large teeth: Pegomya solennis **

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

101b Heteroderidae: trifolii

101c Meloidogynidae: Meloidogyne hapla

102 – Acari

102a Eriophyidae: Callyntrotus polygoni

103 – Coleoptera

103a Curculionidae: ? Pelenomus velaris

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe polygoni

109b Peronosporaceae: Peronospora polygoni

110 – other causers

110a Fungi, Mycosphaerellaceae: Ramularia rubella

110b Fungi, Synchytriaceae: Synchytrium aureum

110c Lepidoptera, Coleophoridae: Augasma aeratella

** It is possibly that also Pegomya setaria,, primarily a miner of Fallopia-species, may occur now and then on Persicaria; there is no possibilty to discriminate the larva from that of P. solennis.

Not included in the key: Agromyza pittodes; Antispilina ludwigi; Mantura rustica.

21/02/2017