Plant Parasites of Europe

leafminers, galls and fungi

gallers on genus Hypochaeris

Dichotomous table for gallers on Hypochaeris

by Hans Roskam

1a On capitula or achenes => 14

1b On vegetative plant parts => 2

2a On leaves => 5

2b On stems => 3

2c All parts of shoot with white crusty blisters, very variable in size; shoot often distorted. H. maculata: Pustula obtusata

3a Shoot axis with tough-walled, plurilocular galls => 4

3b Shoot axis with spongy pale green galls of various shape, length and position, usually on all sides, often elongate, massive, ± twisted or curved. Close to the capitula, also extending into the receptacle. H. maculata, radicata: Ditylenchus dipsaci

4a Stem with up to 40 mm long and 7 mm thick, plurilocular, usually spindle-shaped or oblong swelling, sometimes occupying the whole shoot axis. Galls in spring; one yellow larva per chamber. H. achyrophorus, glabra, laevigata, radicata: Phanacis hypochoeridis

4b Shoot axis, often at the stem base, with one-sided callosity, up to 5 mm long with rotund larval chamber. Hypochaeris spp.: Napomyza lateralis

5a Galls on the leaf blade, not involving veins => 11

5b Galls on main- or secondary veins, partially extending to the leaf blade; massive => 6

6a The gall development expands from the midrib to the leaf blade, or affects mainly the secondary venation => 7

6b The gall formation is restricted to the vein => 7

7a Spongy, short spindle-shaped galls, but variously elongated, protruding on both sides of the vein, pale green with ± rugose surface, often extending over a wide area of the leaf blade, occasionally also running only from the major lateral veins and causing bends. Many eelworms inside the loose gall parenchyma. H. glabra, maculata, radicata, uniflora: Ditylenchus dipsaci

7b Venation of irregularly margined and pale- or yellow green upward arched areas swollen, often ± reddened, the underside protruding in relief. Many spores in the vascular tissue. H. radicata: Protomyces cf. kriegerianus

8a Elongated soft swelling, emerging at the leaf base and narrowed towards the top, is caused by fly maggots => 10

8b Up to 6 mm long swelling, especially prominent on one side of the leaf => 9

9a Closed, egg-shaped, thin- but tough-walled, unilocular swelling. H. glabra, maculata, radicata: Aulacidea andrei

9b Inconspicuous swellings, up to 2 mm long, ± egg-shaped, yellow margined with covering of cinnamon brown spores, usually on the underside of the youngest, ± curved leaves. H. glabra, radicata, maculata: Puccinia hieracii

9c Similarly has been recorded on H. uniflora the close relative: Puccinia montivaga

9d Similarly on H. achyrophorus the close relative: Puccinia marquesii

10a About 3 (5) cm long occasionally slightly reddened galls on smaller leaves which are sometimes extending to the upper side of the terminal third part of the leaf blade. H. radicata: Phytomyza cecidonomia

10b Corresponding galls in the larger leaves, hardly conspicuous, on H. maculata: Phytomyza sp.

11a Galls lacking additional pubescence => 12

11b Leaf blade folded and reddened; in the folds on the upperside white, felt-like, pubescence, might be accompanied by rolling of the leaf margin. H. glabra, radicata: Aceria hypochoerina

12a Galls on expanded leaf blade => 13

12b Leaf blade upward folded, containing apterous green aphids about 1 mm long. H. maculata, radicata: Aphis hypochoeridis

13a Leaf blade slightly deformed, with irregular, weak, one-sided open bulges. H. radicata: Craspedolepta flavipennis

13b Leaf blade with several distinctly protruding pustules on the upperside, which are surrounded by a broad yellow-green to reddish margin. On the leaf underside clearly recognizable red-yellow larva is situated in spongy parenchyma under the epidermis. H. glabra, radicata: Cystiphora sp.

14a Malformations of the capitula => 16

14b Malformations of the achenes => 15

15a Capitula disfigured, with patch of stunted florets and their achenes at side of receptacle; containing yellow, jumping larvae. H. glabra, maculata, radicata: Contarinia hypochoeridis

15b Achene deformed to a 3 mm long, rotund-oval longitudinally grooved gall. One white larva. H. radicata: Unidentified tephritid fly

16a Capitula small and not opening, swollen. H. uniflora: ? Stylia sp.

16b In ungalled capitula of Hieracium spp.: Campiglossa achyrophori

Last modified 18.xi.2023