These thrips live hidden inside the leaf and flower sheaths of their host plants where they suck sap, usually occurring in groups.

After two larval stages they develop into non-feeding prepupae and may drop off onto the soil.

[3] The thrips can remain inside the corms of gladiolus over winter, causing them to ooze sap from the wounds, turn brown and sticky.

These corms are the main source of infestation in growing plants the following year; the emerging leaves are tunnelled and appear silvery at first, turning brown later.

[3] Other damage may be brown buds, discoloured or streaked blooms, and bleached or distorted flower spikes.