Dichotomous table for gallers on Convallaria majalis
by Hans Roskam
1a On flowers or leaves => 2
1b Roots with nodular- to spindle-shaped swellings of a few mm long. Meloidogyne hapla
2a Flower buds slightly swollen, not opening. Containing several ivory-coloured jumping larvae. Contarinia convallariae and/or C. polygonati
2b Leaf blade with many small galls, about 5–7 mm long, up to 4 mm broad, which only protrude when occupied. After departure of the larvae the at first pale green infestation sites show conspicuous green-margined spots on prematurely yellowing leaf blades. Unidentified gall midge
2c Aphids on underside of leaves. The leaves develop large yellow spots and become desiccated. Aulacorthum speyeri