gallers on Onobrychis

1a On parts above ground => 3

1b On roots => 2

2a Nodular swellings of the root. O. viciifolia: Meloidogyne arenaria

2b Cylindrical nodules, up to 8 mm long, apically usually flattened or partitioned, which are laterally inserted into main- or secondary roots. O. viciifolia:
Rhizobium leguminosarum

3a On vegetative organs => 5

3b Malformations of flowers or immature fruits => 4

4a Ovaries of young flowers swollen. Perianth shortened. Corolla ± spreading; calyx conspicuously widened and especially bulging on one side. Containing a curved larva. O. viciifolia: Holotrichapion pisi

4b Flowers swollen, unopened. Larvae gregarious, lemon-yellow, jumping. O. arenaria, montana, viciifolia: Contarinia onobrychidis

4c In flower galls of Onobrychis sp. also non-jumping larvae of Dasineura floralis

5a Galls on single or many leaflets => 9

5b Galls on stem, petiole or midrib => 6

6a The inducers live inside the galls => 7

6b Petioles or midrib with single spindle-shaped swelling, also several broad swellings. Infestation strongly widened in the middle, bent, with a rimmed depression containing the inducer. The galls often develop gregariously on stems, with curved bulges containing several depressions. O. arenaria: Planchonia arabidis

7a Galls with tough wall => 8

7b Spongy, pale green, ± wrinkled swellings of variable expansion on stems and leaf axis of young plants. O. viciifolia: Ditylenchus dipsaci

8a Shoot axis with compact, multi-chambered swelling, up to 30 mm long. Larval chambers in several rows, each chamber containing a single white larva. O. arenaria, viciifolia: Aylax onobrychidis

8b About 5–8 mm long, spindle-shaped swellings in shortened inflorescence axis, often hidden by the clustered flowers. Galls each containing a single larva. O. arenaria, montana, viciifolia: Hemitrichapion reflexum

9a Leaf galls caused by gall midges => 10

9b Galls contain mites. Leaflets folded, irregularly bent, not fleshly thickened. Malformation usually on all leaflets of many leaves. O. arenaria, montana, viciifolia: Aculus longifilis

10a Leaflets folded together upwards, pod-like, fleshy thickened. On young leaves usually all, on older, often only several leaflets infected. Larvae gregarious, yellow-white. O. aequidentata, montana, viciifolia: Bremiola onobrychidis

10b Leaf galls. Onobrychis sp.: Janetiella foliicola