Impatiens balsam

Dichotomous table for leafminers

1a mine small, full depth; larva grey, with distinct head and feet; older larvae live free among spun leaves => 2

1b mine larger, upper- or lower-surface; larva a colourless maggot, mines lifelong => 3

1c galls, etc => Tables for all parasites per species

2a larva: pinacula colourless (the bases of the setae themselves are black) : Cnephasia incertana

2b pinacula black: Cnephasia asseclana

3a irregular, strongly widening gallery; frass in small lumps, pearl chains or longer strings; pupation external; very common on this host: Phytoliriomyza melampyga

3b mine a slender gallary throughout; frass in discrete grains; pupation within the mine, in a, generally lower-surface, pupal chamber; uncommon on this hostplant: Chromatomyia horticola

mod 9.x.2017