Plant Parasites of Europe

leafminers, galls and fungi

gallers on Veronica

Dichotomous table for gallers on Veronica

by Hans Roskam

(incl. Paederota bonarota, lutea; Pseudolysimachion longifolium, spicatum, spurium)

1a On parts above ground => 2

1b Roots with small nodular to spindle-shaped swellings. Veronica spp.: Meloidogyne hapla

2a On inflorescences, flowers or fruits => 36

2b On stems, shoot tips or leaves => 3

3a On stem parts below shoot tip => 9

3b On tips of main- and side shoots => 4

4a Galls irregular, tuft- or ball-like => 7

4b Galls almost regular, bud-like or pouch-shaped => 5

5a Terminal leaf pair folded upwards together, narrowed, thickened, especially basally discoloured or reddened. V. scutellata, serpyllifolia, anagallis-aquatica, beccabunga => 6

5b Terminal leaf pair folded together, pouch-like, swollen, thickened. Transformed into a uniform, usually broad conical, sometimes laterally flattened, 2-valved, 5–10 mm long gall. On glabrous Veronica species glabrous and inconspicuous, sometimes reddened basally; on pubescent hosts ± strongly to even white-woolly haired and often of conspicuous size. Containing orange-red larvae. Veronica spp.: Jaapiella veronicae

= Inquilines: Whitish-yellow midge larvae of Macrolabis incolens

6a On V. scutellata, etc. Terminal pair of leaves folded together in an erect, reddened, spindle-shaped gall. Containing several orange-red larvae: Dasineura similis

6b Similar, however much smaller, glabrous malformations on V. serpyllifolia: Jaapiella veronicae

7a Malformations caused by gall mites on clustered terminal vegetative, or generative parts => 8

7b Shoot tip stunted, disfigured; flowers greened. Containing red larvae. V. fruticans: Dasineura jaapi

8a Tip of generative or vegetative shoots severely stunted, organs densely clustered, variously disfigured; all green parts abnormally pubescent. V. alpina (incl. subsp. pumila), chamaedrys, fruticulosa, officinalis: Aceria anceps

8b Similar, ± strongly pubescent malformations on V. aphylla, fruticans require further analysis. Unidentified gall mite(s)

8c Vagrant mites on the underside of the leaves. At high densities the underside of the leaves may turn violet. V. chamaedrys, longifolia: Aculus latus

= This species is also reported as an inquiline of Aceria anceps

9a Galls locally, of more or less same shape, only rarely longer than 10 mm; on stems and leaves => 24

9b Malformations of largely indefinite shape, depending on organ; malformations of leaves and partially simultaneously on stems => 10

10a Malformations distinguished by excessive pubescence or down caused by branched conidiophores => 20

10b Malformations made conspicuous by rolling or curling of leaves, or spongy swellings on young plants => 11

11a Malformations of leaves, with or without involvement of stem => 12

11b Young plants severely stunted. Stem stunted, swollen, spongy. Surface of gall ± undulate, wrinkled, pale. Tissue brittle, necrotic. Swellings to various extent in closed or loose form on petiole, on the ± disfigured leaf blades as well as encroaching onto further developing stem parts. V. agrestis, arvensis, hederifolia, opaca, peregrina, persica, serpyllifolia, Pseudolysimachion spicatum, etc.: Ditylenchus dipsaci

= Also locally defined galls on stems and leaf veins of V. chamaedrys, persica might be attributed to this eelworm, causing minor damage – isolated galls on shoot parts – on young plants.

12a Various malformations caused by aphids, usually of several terminal leaves => 14

12b Malformations caused by spittlebugs, mites or thrips => 13

13a Upward rolls of leaf margin, containing single or several froth-covered nymphs. V. austriaca: Unidentified thrips

= Haplothrips aculeatus is reported as causer of such gall-like malformations

13b Leaves arched, with deflected margins, leaf blades curled and deep green close to infestation. Depending on leaf size, several to many, similarly disfigured leaves accumulated, almost nest-like, on ± stunted and distorted stems. Veronica spp.: Philaenus spumarius

14a Often minor, facultative malformations on various Veronica species are caused by various non-specific, differently coloured aphids, green, more rarely yellowish or reddish => 15

14b Similar malformations caused by black aphids. Veronica spp.: Aphis fabae

15a Antennae shorter than body, apterous aphids more or less dull coloured. Aphid 1–2 mm long => 18

15b Antennae of aphid as long as or distinctly longer than the very glossy body. Aphid often longer than 2 mm => 16

16a Siphunculi cylindrical or slightly conical, without swelling, 1/5–1/4 as long as body. Winged aphids with black head and thorax as well as with dorsal dark transverse stripes on abdomen, or only weakly pigmented => 17

16b Siphunculi in distal 2/3 distinctly swollen, 1/7–1/6 of body length. 1.6–2.0 mm, pale olive-coloured to greenish. Froth-covered milky coloured nymphs. Alates dark pigmented and with large, black central spot on abdomen. Veronica spp.: Myzus ascalonicus

17a Aphid pale straw-yellow, green or reddish; adult apterous often with dark spotted pattern. Siphunculi either completely or only terminally dark. Aphid about 1.9–3.1 mm long, alternating with Ribes species. Veronica spp.: Nasonovia ribisnigri

17b Light yellowish-green, base of siphunculi darker green. Siphunculi pale with blackish tip. Length 2–3 mm. Body pear-shaped, broadest distally. Veronica spp.: Aulacorthum solani

18a Siphunculi of apterous aphids black => 19

18b Siphunculi of apterous aphids yellowish-green with brown tip. Apterae rotund-oval, alternating with Rhamnus species. Veronica spp.: Aphis nasturtii

19a Siphunculi as long as cauda, body yellowish-green. Primary host Frangula dodonei. Veronica spp.: Aphis frangulae subsp. beccabungae

19b Siphunculi distinctly longer than cauda. All gradations from dark green to dirty-yellow are found in varying amounts. Veronica spp.: Aphis gossypii

20a Malformations covered with branched conidiophores => 22

20b The ± dense erinea consist of unbranched hairs of host plant => 21

21a Plant abnormally pubescent over extensive areas on leaves, stems and other green parts, sometimes additionally disfigured. V. alpina, chamaedrys, fruticulosa, officinalis, serpyllifolia: Aceria anceps

21b Similar, felt-like pubescence mainly on leaf blades. Paederota bonarota: Aceria bonarotae

22a Malformation of many leaves often over extensive areas ± etiolated shoots => 23

22b Malformations mainly on single or several terminal leaves, localised or expanded, bladder-like pale-green swellings. V. beccabunga, etc.: Peronospora grisea

23a On V. anagallis-aquatica: Peronospora aquatica

23b On other Veronica species. Depending on response ability of host, results in minor to ± distinct malformations. Conspicuous malformations only on early systemically infected organs, which show distinct etiolations:

a On V. agrestis, arvensis, chamaedrys, persica, polita, teucrium, verna:
Peronospora agrestis

b On V. hederifolia, triphyllos: Peronospora arvensis

24a Malformations bearing sori on their surface => 34

24b Galls without sori on their surface => 25

25a Single galls up to 3 mm long => 31

25b Galls usually longer => 26

26a Stem galls below the inflorescence or at least on the nodes of upper stem parts => 30

26b Galls predominantly on basal stem, exceptionally also on middle stem parts => 27

27a Causers are inside the galls => 28

27b Irregular spindle-shaped, sometimes curved swellings of variable length, with single or several rimmed depressions on their surface containing the causer. V. officinalis, chamaedrys: Planchonia arabidis

28a Galls with glabrous surface, containing larvae in chambers; V. serpyllifolia, Pseudolysimachion spicatum Galls with glabrous surface, containing larvae in chambers; V. serpyllifolia, Pseudolysimachion spicatum => 29

28b Stem with internodes or nodes with spindle-shaped, often ± curved and reddened swellings of variable length; surface of swellings undulately wrinkled. Causers inside galls. Similar, smaller galls sometimes on leaf veins. V. chamaedrys, etc.: Ditylenchus dipsaci

29a Shoots conspicuously stunted, in basal or middle parts with very irregularly shaped, about 3–7 mm long, nodular, one- to two-chambered galls. Each chamber containing a single larva. Mainly V. serpyllifolia: Gymnetron melanarium

29b Stem base, sometimes also root collar and upper root part, with conspicuous, rotund, up to about 12 mm long, one-chambered gall. Containing a single larva. Pseudolysimachion spicatum: Gymnetron erinaceum

29c Beetle larvae in locally strongly swollen stems. V. anagallis-aquatica: Gymnetron vittipenne

= Gymnetron aper has been reported as causing swelling of stem of V. officinalis

30a Shoot axis with spindle-shaped or acuminated, barrel-shaped to oblong cylindrical swellings, often distorted, up to 3 (4) mm thick. Smaller galls also on leaf- and flower peduncles, as well as on leaf veins; cells contain cinnamon-brown spore masses. Mainly on V. arvensis, hederifolia, triphyllos, also recorded from V. chamaedrys, filiformis, fruticans: Sorosphaerula veronicae

30b Shoot axis swollen below inflorescence. Pseudolysimachion spicatum: Jaapiella veronicae

= On Pseudolysimachion spicatum swollen leaf buds on stem (first midge generation) and flower buds (second generation) are caused by Dasineura spicatae

= Similar stem swelling, but associated with malformation of shoots or clustered flower buds, especially on higher growing species. Very variable galls of Jaapiella veronicae

31a Galls distinctly protruding at upper-, as well as on underside => 32

31b Leaf blade with rotund, up to 2 mm long spots, ± slightly swollen, at first dirty white, then brownish containing spores. V. serpyllifolia: Entyloma veronicae

32a Galls less than 1 mm across, wart-shaped; usually in large numbers on underside of basal leaves; sometimes on petioles and stems; solitary or joined, crust-like => 33

32b Leaf blade with reddish swellings on upperside. V. chamaedrys: Unidentified thrips

33a Multi-cellular warts, hemispherical, with depressed top. Nutritive cell with colourless content. V. anagallis-aquatica, beccabunga, chamaedrys, scutellata: Synchytrium globosum

33b Warts minute, coalescing into small brown-red spots. Galls simple, often hardly protruding; adjacent cells often not enlarged. V. scutellata: Synchytrium johansonii

34a Sori mainly on leaves, usually developing gregariously, protruding on underside, pad-shaped non facultatively – conspicuously swollen socket, covered with brown telia. Pads on leaf blade rotund, on upperside usually ± depressed; on venation oblong-oval to spindle-shaped on distinctly protruding bulges => 35

34b Sori usually ± elongate, chestnut-brown, mainly on variously distorted basal stem parts and on midribs on underside of more basal leaves. Spores glabrous or wall of upper cell with small warts. The mycelium developing telia usually expanded. V. alpina, aphylla, bellidioides: Puccinia albulensis

35a On V. montana, Pseudolysimachion spicatum, spurium. Sori pale brown, usually arranged in circles on sometimes weakly arched pads slightly sunken on upperside. Stalks of telia not brittle: Puccinia veronicae

35b Infestation similar. Sori developing in spring compact, pad-like arched on underside, depressed on upperside Teliospores thin-walled, with compact stalk. Sori with dark, thick-walled teliospores on brittle stalks develop in circles during summer. V. austriaca, ponae, Pseudolysimachion longifolium, spicatum, etc.: Puccinia albulensis

= The rare rust fungus Puccinia veronicae-longifoliae has also been recorded from Pseudolysimachion spicatum

36a On inflorescences or flowers => 39

36b Malformations on ovaries or fruits => 37

37a Ovaries unchanged outwardly. Malformation confined to ovula => 38

37b Ovaries strongly swollen, rotund-oval, sometimes with laterally ± shifted, arched, more rarely depressed apical part; galls ± globular, up to 6 mm across, wall succulent. Corolla and stamens dropping early. Containing a greenish tinged, dirty-yellow, black-brown headed larva, actively moving if disturbed. V. anagallis-aquatica, anagalloides, scutellata: Gymnetron villosulum

38a Stalk of ovary temporarily strongly swollen; other flower parts poorly developed. Tissue of entire ovary soon destroyed and filled with black, slightly brown-tinged spores. V. hederifolia, campylopoda: Schroeteria decaisneana

38b Ovaries temporarily swollen. Tissue inside soon replaced by a blue-grey to black-grey spore mass. V. acinifolia, agrestis, arvensis, persica, triloba, triphyllos, verna: Schroeteria delastrina

39a Flowers ± greened, leafy, also double or poorly developed, disfigured. Malformations often over ± extensive areas of inflorescence, sometimes abnormally pubescent. Caused by aphids or gall mites => 43

39b Flowers unopened, swollen => 40

40a Malformations caused by larvae which lack obvious, large head capsule => 42

40b Malformation mainly of the ovary caused by larvae with distinct head capsule => 41

41a In slightly swollen ovaries lives a seed-eating larva. Perianth of early infected flowers sometimes enlarged and unopened. V. beccabunga, scutellata, etc.: Gymnetron beccabungae

41b Also on V. anagallis-aquatica has been reported as causer of succulent ovary galls: Gymnetron veronicae

41c lowers unopened, swollen. V. arvensis, etc.: Gymnetron sp.

42a Flowers unopened, inflated, globular; each containing a single larva. When inflorescences are infected early, the largely undeveloped buds remain clustered, tuft-like; containing the orange-red coloured larvae. Veronica spp.: Jaapiella veronicae

42b Flowers swollen. Corolla slightly larger than calyx. Containing a single orange-yellow larva. V. anagallis-aquatica, beccabunga, scutellata, Pseudolysimachion spicatum, etc.: Dasineura similis

43a Malformations bearing aphids => 48

43b Malformations caused by gall mites => 44

44a Axis of inflorescence ± stunted; flowers variously disfigured => 47

44b Inflorescence not stunted or ± excessively branching; flowers disfigured => 45

45a Malformations without excessive branching => 46

45b Inflorescence ± excessively branched. Flowers ± greened or leafy, sometimes unopened, joined to almost cauliflower-like balls. Axial parts and calyx ± abnormally pubescent. V. chamaedrys, officinalis, prostrata, serpyllifolia, etc.: Aceria anceps

= Almost witches’ broom-like malformations with severely disfigured greened and leafy flowers on Pseudolysimachion longifolium could not be attributed to a particular cause

= Greening of flowers on V. persica is caused by viruses

46a Flowers double by multiplication of corolla leaves. In axils of corolla leaves sometimes short-stalked buds or similarly disfigured flowers. Stamens and ovaries aborted. V. officinalis: Unidentified gall mite

46b Flowers greened, calyx lobes ± enlarged and thickened. Paederota lutea:
Unidentified gall mite

47a Upper part of inflorescence with shortened midrib. Flowers ± greened. Bracts reduced. Pseudolysimachion longifolium: cf. Aceria anceps

47b Rachis of inflorescence and flower peduncles shortened, flowers clustered; calyx ± abnormally pubescent; other flower parts normal. V. alpina, bellidioides: Aceria anceps

48a Axis of inflorescence stunted and ± distorted. Flowers clustered, ± unopened, disfigured. Pseudolysimachion longifolium, spicatum: Aphis pseudolysimachiae

48b Stalk of inflorescence stunted. Flowers poorly developed; clustered, ball-like. V. anagallis-aquatica: Aphis frangulae subsp. beccabungae

Last modified 24.viii.2020