Plant Parasites of Europe

leafminers, galls and fungi

gallers on Pastinaca

Dichotomous table for gallers on Pastinaca

by Hans Roskam

1a On parts above ground => 3

1b On root or root collar => 2

2a Roots with nodular swellings. P. sativa: Meloidogyne hapla

2b Conspicuous proliferations on root collar. “Root cancer”. P. sativa: Agrobacterium tumefaciens

3a On all parts of flowering or fruiting inflorescence => 14

3b On vegetative parts => 4

4a Malformations mainly on the leaf blades of leaflets or leaf sheaths => 8

4b Galls on stems, petioles and midrib or mainly on venation of leaflets => 5

5a Causers live inside galls => 7

5b Causers on galls or fruiting on surface => 6

6a Midrib of rosette leaves of young plants with smaller, or more expanded, sometimes arched, bulging, sometimes reddened swellings, which contain one or several scale insects in depressions on surface. P. sativa: Planchonia arabidis

6b Conspicuous yellow swellings, soon bearing spermogonia and aecia. P. sativa: Uromyces lineolatus

7a pindle-shaped, compact, glabrous, bulging swellings on axial parts. P. sativa: Protomyces macrosporus

7b Petiole often severely stunted, especially spongy at base. Surface wrinkled, sometimes with longitudinal fissures. Infected venation of leaflets ± swollen especially at base of leaf blade, leaf blade curled. P. sativa: Ditylenchus dipsaci

8a Malformation of leaflet leaf blade caused by midge larvae, aphids or cercopids => 9

8b Sheaths of younger leaves ± strongly swollen, slightly thickened. Buds ± stunted. Larvae red. P. sativa: Unidentified gall midge

9a The disfigured leaf blades show slight folds open on upper side or are mainly deflected downwards, caused by aphids or cercopids => 10

9b Depending on stage of development during infestation, the halves of leaflets remain partially or completely folded upwards; main venation ± swollen. Containing several white larvae. P. sativa: Macrolabis heraclei

10a Malformations caused by aphids => 11

10b Leaf midrib shortened and curved, the accumulated leaflets deflected, curled, locally deep green. P. sativa: Philaenus spumarius

10c Leaf, or several leaves, folded, curled or crumpled, often yellowish, with leaf blade and veins ± thickened; containing flattened froth-covered nymphs. P. sativa: Trioza apicalis

11a Aphids ± green => 12

11b Aphids black; leaflets deflected. Leaf blade weakly swollen. P. sativa: Aphis fabae

12a Leaflets rolled inwards and downwards => 13

12b Tips of leaflets strongly curled, at first with small folds, open on upperside; aphids inhabiting the weakly swollen leaf sheaths later on and disfiguring young side shoots as well as umbels. P. sativa: Hyadaphis foeniculi

13a Leaflets deflected downwards, partially curled. Aphid 1.8–2.8 mm long, yellowish-green. Siphunculi slightly club-shaped and pale, almost three times as long as the same coloured cauda, which has at its base a finger-like appendage. P. sativa: Cavariella pastinacae

13b Similar minor malformations. P. sativa: Cavariella theobaldi

13c Leaflets rolled downwards. Aphid lacking tail-like appendage at base of cauda. P. sativa: Semiaphis pastinacae

14a On fruits => 19

14b On inflorescences or flowers => 15

15a Malformation mainly of complete inflorescence or inflorescence stalk => 16

15b Flowers swollen, unopened; inflorescence often ball-like. White larvae inside flower. P. sativa: Contarinia sp.

16a Galls locally on stalks of inflorescence => 18

16b Variable malformations of complete inflorescence => 17

17a Caused by aphids. P. sativa: Hyadaphis foeniculi

17b Ball-like malformations of inflorescence associated with greening on P. sativa, further growth of flowers and stronger pubescence caused by an unidentified gall mite

17c Strong clustering of inflorescence caused by maggots. P. sativa: Cause unknown – ? dipteran

18a Centre of umbel or stalk of umbel ± swollen, club-shaped. Inner wall covered with mycelium. Containing a red larva. P. sativa: Lasioptera carophila

18b Stalk of partial umbel with club-like swelling at base. P. sativa: Unidentified gall midge

19a Fruit slightly swollen; seed aborted; containing a yellow, jumping larva. P. sativa: Contarinia pastinacae

19b Fruit strongly inflated, bladder-like; galls ± reddened, protruding above the umbel; 1 (3) orange-red larvae. P. sativa: Kiefferia pericarpiicola

Last modified 22.iii.2020