gallers on Phaseolus

1a On roots or root collar => 4

1b On stems or leaves => 2

2a On leaf blade or -stalk => 3

2b Stem with spongy, pale green swelling; leaves stunted and ± curled. P. vulgaris: Ditylenchus dipsaci

3a Leaves loosely deflected at margin, slightly discoloured and curled, caused by black aphids. P. vulgaris: Aphis fabae

3b Minor hypertrophies on leaf axis, occasionally also slight arching of infected, usually pale green parts of leaf blade. Caused by a mycelium developing spermogonia and aecia. P. acutifolius, coccineus, vulgaris: Uromyces appendiculatus

4a Malformations on root => 5

4b Compact, succulent, mainly one-sided proliferations on root collar. “Root cancer*. P. vulgaris: Agrobacterium tumefaciens

5a Roots with distinctly protruding galls => 6

5b Roots not changed from the outside; inside with giant cells; temporarily bearing ± lemon-shaped lighter to darker egg capsules. Phaseolus vulgaris: Heterodera sp.

6a Nodular swellings, often occupying all sides of the complete root body, bearing several side roots. Phaseolus vulgaris: Meloidogyne hapla

6b Globular or egg-shaped nodules, up to about 5 mm long, inserted laterally, usually many and occasionally clustered. Phaseolus vulgaris: Rhizobium phaseoli