Plant Parasites of Europe

leafminers, galls and fungi

gallers on genus Melilotus

Dichotomous table for gallers on Melilotus

by Hans Roskam

1a On above ground parts => 3

1b On roots => 2

2a Nodular or spindle-shaped swellings. M. officinalis: Meloidogyne hapla

2b Globular or up to 8 mm long, cylindrical, forked or coral-like branched nodules. Melilotus spp.: Sinorhizobium meliloti

3a On inflorescences, flowers or fruits => 9

3b On vegetative organs => 4

4a On shoot axis or leaves of fully developed plants => 5

4b Young plants considerably stunted. Stems shortened, spongy, thickened. Leaves clustered, occasionally the axial parts swollen, leaf blades distorted. Melilotus spp.: Ditylenchus dipsaci

5a On shoot axis => 7

5b On leaves => 6

6a Leaflets folded upwards, halves at base ± adnate and swollen, together with midrib, into a globular or oblong gall, up to 6 mm long, protruding on underside. Containing a yellowish beetle larva. M. albus, altissimus, dentatus, officinalis: Tychius crassirostris

6b Weaker swelling of midrib of leaflet. Containing a single larva. M. albus, altissimus, officinalis: Tychius meliloti

7a Inducer inside the gall => 8

7b Acuminate-rotund- to oblong oval, often snapped off, or ± bent, expanded bulging swellings of stem, containing in rimmed depressions the inducer. M. dentatus, officinalis: Planchonia arabidis

8a Rotund to spindle-shaped swelling, 5–15 mm long. The pith containing a maggot. M. albus, dentatus, officinalis: Melanagromyza submetallescens

8b Weak swelling, inside a compact pith containing several white larvae. M. albus: Unidentified dipteran

9a All flowers of a plant occasionally disfigured and ± pubescent. Calyx hardly disfigured, corolla and anthers often reduced, ovary developing into a short, leafy cone, transformed together with the axils of stipules, developing shoots into a ± dense leafy inflorescence. M. albus, altissimus, dentatus, officinalis: Unidentified gall mite

9b Flower buds swollen, unopened. M. altissimus, officinalis: Contarinia sp.

9c Flowers strongly greened; beetle larva living inside stem just below inflorescence. M. albus, altissimus, dentatus, officinalis: Stenopterapion meliloti

9d Beetle larvae feed within the pod on the developing seed; this may cause some galling of the pods. M. albus, ? altissimus, officinalis: Tychius breviusculus

Last modified 18.xi.2023