Plant Parasites of Europe

leafminers, galls and fungi

gallers on Pisum

Dichotomous table for gallers on Pisum

by Hans Roskam

1a On root collar or on above ground organ => 4

1b On roots => 2

2a Roots with nodules => 3

2b Root system and shoot parts ± atrophied; roots unchanged on the outside, giant cells inside; later on bearing poppy-seed sized, lemon-shaped, whitish to brownish egg capsules. Pisum spp.: Heterodera goettingiana

= Also recorded on Pisum species is the clover cyst eelworm H. trifolii. More strongly infected plants often lacking nodules

3a Roots slender or nodular swellings bearing side roots. Pisum spp.: Meloidogyne hapla

3b Oval or cylindrical nodules, often terminally broadened and ± forked or lobed, hand-shaped or coralline-like subdivided, at maturity inside ± flesh-red, up to about 8 mm long, occasionally clustered; laterally inserted on main- and side roots. Pisum spp.: Rhizobium leguminosarum

4a On flowers or fruits => 11

4b On vegetative parts => 5

5a On aerial organs => 7

5b On root collar => 6

6a Proliferations conspicuous, closed, at surface not subdivided. “oot cancer”. P. sativum: Agrobacterium tumefaciens

6b Witches’ broom-like malformation. Accumulation of severely stunted or fleshly thickened, lobed, pale, aerially greening shoots. “Leafy gall”. P. sativum: Rhodococcus fascians

7a Older plants ± severely stunted, leaves and, when present, flowers variously disfigured, or malformations of shoot tips => 8

7b Stems of young plants severely stunted, often conspicuously spongy thickened and ± distorted. Lateral organs stunted, ± bent and curled at base, also swollen; growth dwarfed. Pisum spp.: Ditylenchus dipsaci

7c Shoot distorted, often with proliferation of buds and russeting of leaves. Pisum spp.: Peronospora viciae

8a Plant completely or largely disfigured => 9

8b Shoot tips stunted to variable degree, leaves including, if present, disfigured flower buds, rosette-like or bushy accumulations, containing many white jumping larvae. P. sativum: Contarinia pisi

9a Malformations caused by aphids => 10

9b Leaves on the ± atrophied shoot tip curled, rolled upwards; leaves and flowers, if present, clustered. If strongly infected, the plant remains small and bushy; larvae very slender, many, up to about 1.5 mm long. Pisum spp.: Thrips angusticeps

10a Several leaves of variously disfigured shoot tips; the leaf blades ± curled and deflected, partially discoloured; containing black aphids Pisum spp.: Aphis fabae

10b Similar malformations caused by green aphids. P. sativum: Acyrthosiphon pisum

11a On flowers => 12

11b Young pods disfigured, sometimes with nodular, discoloured swellings. Usually containing many white, jumping larvae. P. sativum: Contarinia pisi

12a Flower buds disfigured and clustered on often severely stunted stalks, especially swollen at base, corolla stunted and strongly curled, unopened; containing many white, jumping larvae. P. sativum: Contarinia pisi

12b Flowers developing into short shoots with scale-like, green leaflets. P. sativum: Unidentified gall mite or virus

Last modified 10.iv.2020