Damage based identification key for endophagous herbivores on Common Reed (Phragmites australis)

Author: Patrick Häfliger ©
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CABI Europe - Switzerland
Rue des Grillons 1, CH-2800 Delémont

Online-Key

Instructions for use
Following the first impression of damage to a shoot, looking for holes and galls leads you to more characteristics of the feeding pattern and finally to the identification of the herbivore(s) causing the predominant damage. Since multiple infestations are possible, shoots need to be examined further to identify all the species present in it. After having found one herbivore, restart the key at #8, and ignore the features connected to the first herbivore found already. Thus, additional species possibly present and causing less obvious damage can be identified.

In a few cases, the key will not lead to a result, although the shoots are obviously dead. This damage can often be assigned to late frost in spring or mechanical damage caused by vertebrates. Sometimes rhizome herbivores feeding in a connected shoot base can weaken neighbor stems.

Careful! In most infested shoots you will find 3-6 mm small whitish fly larvae and/or pupae living in feces and/or rotten plant tissue. They are inquilines and can be ignored here.

Some expressions used to describe shoot anatomy or larval types are explained with graphs in the glossary.

Pic. 65: Gall of Lipara lucens

shoot with apical gall (picture 65)

no apical gall

apical gall usually twisted (picture 20); gall formed by leaves glued together, with dark deformed cells, and eggs, larvae and/or adults of 0.1-0.2 mm long mites (picture 12)
Steneotarsonemus phragmitidis

Pic. 20: Gall of Steneotarsonemus phragmitis
Pic. 12: Cut through shoot tip infested by Steneotarsonemus
phragmitidis
Pic. 64: Dead and shortened uppermost leaf of a Lipara gall

Pic. 22: Gall of Lipara lucens without leaves
Pic. 23: Gall of Lipara rufitarsis without leaves
Pic. 60: Gall of Lipara pullitarsis without leaves
Pic. 24: Gall of Lipara similis without leaves

apical gall not twisted, gall built by (2) 4-13 shortened internodes (pictures 22-24, 60), with a single 0.6-1.2 cm large fly larva right below or above the growing point (often with several smaller fly larvae or pupae), uppermost leaf often shortened and dead (often hidden by next healthy leaf) (picture 64)
Lipara spp.

gall with more than 7 stunted internodes (picture 22), gall walls usually strongly lignified, gall internodes 2-3 times thicker than internode below; larva thick and large (8-12 mm long), feeding in gall internodes below growing point (picture 7)
Lipara lucens

Pic. 22: Gall of Lipara lucens without leaves
Pic. 7: Larva of Lipara lucens feeding in shortened
internodes below growing point

gall with less than 7 stunted internodes; larva smaller (5.5-10 mm)

gall with 5-6 stunted internodes (picture 23, 60)

Pic. 23: Gall of Lipara rufitarsis without leaves
Pic. 24: Gall of Lipara similis without leaves
Pic. 3: Lipara similis larva feeding in tube formed by the
uppermost 2 leaf sheaths

gall usually with 2 (but sometimes up to 4) stunted internodes (picture 24), gall not thickened; the 2 uppermost leaf sheaths form a tube above the growing point where the larva feeds (picture 3), larva with dark sclerotized ends
Lipara similis

growing point eaten through, larva feeds below growing point; mainly on thinner shoots (base diameter 2-5 mm), gall often flattened
Lipara rufitarsis

growing point not eaten through, larva feeds above growing point, mainly on thicker shoots (base diameter > 4 mm)
Lipara pullitarsis

(only side shoots) entire side shoot thickened and shortened; after taking away the leaf sheaths, an obvious black line appears on some of the shortened internodes (picture 29); gall midge larvae within black fungus in internodes
Lasioptera arundinis

Pic. 29: Side shoot internodes
infested by L. arundinis

not as described above

shoot obviously damaged; at least tip definitely dead or broken off (pictures 10 and 6)

Pic. 10: Dead reed shoot
Pic. 6: Dead shoot tip, broken

tip not obviously damaged

shoot with hole

no hole, no emergence window

with emergence window > 3 mm

no emergence window, or emergence window < 3 mm

entrance hole 0.4-0.8 mm large; fine whitish droppings in internode with hole; normally on upper part of shoot

10*

not as described above, normally on lower part of shoot

single, 0.5-1 cm long moth larva with 5 brown longitudinal lines
young Chilo phragmitellus larva (Type I)

11*

often more than one larva in stem; 0.5-1 cm long caterpillar larvae with 4 brown longitudinal lines (picture 27)
Chilo phragmitellus (Type II)

1-4 emergence windows/holes (c. 2 mm wide) right below a node of lower internodes, c. 8 mm long cocoon inside (picture 21), which is empty after mid-July; if pupa present, similar to a gall-midge, but with characteristic 4 thorns on each side (picture 4)
Thrypticus smaragdinus

Pic. 21: Cocoon of Thrypticus smaragdinus
Pic. 4: Pupa of Thrypticus smaragdinus
Pic. 27: Larva of Chilo phragmitellus (Type II)

12*

usually only 1 emergence window per internode, 2-3 mm wide; c. 1.4 cm long moth pupa inside with spikes at the end (picture 74)
Chilo phragmitellus (Type II)

12**

often several ca. 0.5 mm wide holes aggregated above a node on lower shoot part, connected to "rice grain galls"; no frass in internode
emergence holes of Giraudiella inclusa

after taking away leaf sheaths: some more or less obvious deformations of the shoot or feeding visible

13*

after taking away leaf sheaths: still no obvious damage

after splitting the shoot: 10-300 yellowish gall-midge larvae associated with black fungus (picture 1), spatula of larvae obvious, mainly in 6th-9th internode, 1-3 internodes infested
Lasioptera hungarica

Pic. 1: Lasioptera hungarica
larvae with associated fungus

14*

no black fungus

inwards protruding rice grain like galls (picture 8), sometimes not completed; from outside c. 5 mm long longitudinal lesions visible (picture 2)
Giraudiella inclusa

15*

no rice grain galls

5-20 yellow-orange gall-midge larvae (picture 19), only in the uppermost internodes, usually associated with a white felt-like fungus; spatula of larvae not obvious
Microlasioptera flexuosa

Pic. 8: Internode infested by Giraudiella inclusa, view from inside
Pic. 2: ..., external view
Pic. 19: Larvae of Microlasioptera flexuosa

16*

no gall-midge larva

moth larva; small entrance hole easy to overlook, fine whitish droppings in internode with hole; normally on upper shoot part

Pic. 15: Feeding mark of Tetramesa phragmitis

17*

white wasp larva(e), often grating marks on a small surface on the felt inside the shoot (picture 15)

17**

no larva, no feeding marks
shoot free of infestation

larva small (2-6 mm), usually 5-20 larvae per internode (picture 16)
Tetramesa phragmitis

Pic. 16: Larvae of Tetramesa phragmitis
Pic. 14: Parasitoid larvae of Tetramesa phragmitis

18*

larva bigger (up to 13 mm) only 1 per internode (picture 14), forming later a 1-1.5 cm long cocoon below the node, boring an exit hole on the lower end of the cocoon in the following year Parasitoid of
Tetramesa phragmitis

no distinct feeding above growing point

19*

distinct feeding above growing point

about 6 mm long dark openings/cavities in the shoot wall (picture 17), sometimes covered with a parchment like layer, with gall-midge larva inside; larva often under the shoot wall above the opening, only on upper internodes, larva usually surrounded by white felt tissue
Giraudiella inclusa

Pic. 17: Gall of Giraudiella inclusa on upper internodes
Pic. 26: bulging gall of Giraudiella inclusa
Pic. 28: bulging gall of Giraudiella inclusa
Pic. 61: Heavy infestation by Giraudiella inclusa

20*

bulging galls on outside of lower internodes (picture 26 and 28)
Giraudiella inclusa

20**

base of one or more uppermost internodes weak and greyish; a few yellow-orange gall midge larvae in the internode, spatula not obvious; internode below often with white felt
Microlasioptera flexuosa

uppermost leaf shortened and dead (picture 9), 5.5-10 mm long fly larva with dark sclerotized ends above growing point (picture 3), often associated with smaller fly larvae or pupae, (2-4 shortened internodes, one thinner than the previous one)
Lipara similis

Pic. 9: Shoot infested by Lipara similis
Pic. 3: Lipara similis larva feeding in
tube formed by the uppermost 2 leaf sheaths

21*

uppermost leaf dead but not shortened, fly larva not with dark sclerotized ends
unidentified Diptera (polyphagous crop pest)

feeding marks and frass starting above growing point; shoot sometimes broken right above growing point

22*

cause of damage below growing point

mine-like longitudinal tracks in several leaves and leaf sheaths (picture 25); intense frass above growing point; 0-8 cm above growing point c. 7 mm long orange-brown fly pupa (empty) (picture 13) within frass and several smaller fly larvae or pupae; if pupa missing, emergence hole of parasitoid instead; 1-2 internodes below growing point often weak; tip often broken off near growing point
Platycephala planifrons

Pic. 25: Mine like longitudinal tracks
in leaves and leaf sheath of a shoot infested
by Platycephala planifrons
Pic. 13: Pupa of Platycephala planifrons

23*

no mine-like tracks in leaves and leaf sheaths

only small amount of frass; 4 mm long fly larva or pupa above growing point
unidentified Diptera (polyphagous crop pest)

Pic. 67: Internode severed by first instar larva
of Archanara geminipuncta

24*

shoot nearly completely dead, usually < 1.10 m long; one internode clearly severed (picture 67); tiny caterpillar entrance hole (0.5 mm), exit hole, but shoot often broken off above severence
damage by first instars of Archanara spp. or Arenostola phragmitidis

with emergence window

25*

without emergence window

emergence window > 3 mm

26*

emergence window < 3 mm

largest hole > 1.2 mm wide, in upper internode; shoot usually
> 1 m long

27*

largest hole in internode < 1.1 mm wide; or tip broken off

feeding marks and frass downwards into rhizome

28*

feeding marks and frass only above ground

infested internodes still strong/stable

29*

at least one infested internode weak, shoot breaking easily; feeding down to the rhizome

feeding ends after few internodes; nodes below feeding undamaged; infested internodes filled on average with less than 50% frass
Chilo phragmitellus or Phragmataecia castaneae, continuation only with larva

Pic. 34: Larva of Schoenobius gigantellus

30*

several nodes below feeding with hole closed with silk; deep in the rhizome yellow-olive-green moth larva (picture 34)
Schoenobius gigantellus

moth larva with 5 brown longitudinal lines, light brown head capsule (picture 18)
Chilo phragmitellus

Pic. 18: Mature larva of Chilo phragmitellus
Pic. 69: Toothed neck shield of Phragmataecia castaneae

31*

moth larva with 2 brown longitudinal lines, light brown head capsule, toothed neck shield (picture 69)
Phragmataecia castaneae

internodes often subdivided by silky lids; only small part of 1 (-2) internodes with intense feeding, but always leaving a thin layer of epidermis intact (characteristic for this species mainly in spring) (picture 55)
Schoenobius gigantellus

Pic. 55: Feeding of Schoenobius gigantellus

32*

no silky lids; internodes more than 50% packed with feces, rhizome internodes apart from a thin layer of the epidermis often totally eaten
Rhizedra lutosa

feeding in upper internodes reaching growing point, or shoot tip broken off

33*

feeding much lower than growing point; moth larva (if present) with 5 brown longitudinal lines
Chilo phragmitellus

feces and feeding mostly restricted above the growing point
Archanara neurica

34*

feces and feeding also below the growing point
A. geminipuncta, A. dissoluta or Arenostola phragmitidis; identification only possible with larvae in spring (see species description)

nodes above and below pupal chamber undamaged; usually no feeding in pupal chamber; entrance hole and emergence window always on the same internode; pupa end without spikes (picture 74)

Pic. 74:Pupa without spikes (Archanara geminipuncta)
Pic. 75: Pupa with spikes (Schoenobius gigantellus)

35*

nodes below and/or above pupal chamber eaten through, or intense feeding in internode; pupa end with spikes (picture 75)

pupa head upwards; emergence window often just below next node; pupa 17-24 mm long; if feeding and entrance hole in upper internode present, probably caused by same species
Archanara geminipuncta

36*

pupa head downwards (13-20 mm long); if feeding and entrance hole present in upper internode, probably caused by same species

pupa in first internode at ground level
Archanara dissoluta

37*

pupa above ground level
Archanara neurica

often several ca. 0.5 mm wide holes aggregated above a node on lower shoot part, connected to "rice grain galls"; no frass in internode
emergence holes of Giraudiella inclusa

38*

no rice grain galls

1 or 2 upper internodes weakened at base, often white felt with 1-20 yellow-orange gall midge larvae (picture 19); sometimes tip broken off
Microlasioptera flexuosa

Pic. 19: Larvae of Microlasioptera flexuosa

39*

no white or grayish felt; frass present

infested parts soft and weak, decaying, or tip broken off

40*

infested parts still strong, tip not broken off

no feeding in internode below internode with hole, tip often broken off at a clean cut
Archanara spp. or Arenostola phragmitidis

Pic. 34: Larva of Schoenobius gigantellus

41*

feeding in internode below internode with hole; restricted to water reed; in one internode small area of intense feeding, but thin layer of epidermis intact; yellow-olive-green moth larva in shoot base or later in rhizome (picture 34)
young Schoenobius gigantellus larva

small entrance hole, c. 0.5 mm, always at the upper end of a leaf sheath on an upper internode; the internode with the hole or more often the internode above is packed with feces and reed shavings;, feeding not much further than growing point, exit hole about 1 mm wide, less than 10 cm from entrance hole; if no exit hole, larva with 2 brown longitudinal lines and toothed neck shield (picture 69)
young Phragmataecia castaneae larva

Pic. 69: Toothed neck shield of Phragmataecia castaneae

42*

entrance hole 0.4-0.8 mm wide, not restricted to end of leaf sheaths; few, fine feces; feeding not reaching growing point

pupa free in the internode

43*

pupa in silky tube, which leads to the emergence window

nodes above pupal chamber usually partly eaten through, but closed by silky lids; pupal case very thin; mainly on water reed; emergence window often below water level
Schoenobius gigantellus

44*

nodes above pupal chamber not damaged, not restricted to water reed
Pseudobissetia terrestrella

pupa segments with serrated/toothed lip; emergence window often several internodes above pupa; all nodes between pupa and emergence window completely eaten through; after emergence only the abdominal part of the pupa case remains in the stem
Phragmataecia castaneae

45*

pupa segments without serrated/toothed lip
Chilo phragmitellus

11/04/07

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