Is there any way to inspect day lilies at this time of year, before they bloom, to determine if they are infected with gall midge? Would there be anything evident in the roots of the plants? Thanks for any advice!
Deformed flower buds are your first indication that they are infested with Hemerocallis gall midge larvae. The buds will have a pinched look and will be smaller than other healthy buds. If you are not sure whether the buds are infested, watch the bud development for a day or two. To control gall midge you must remove all infested buds. Put them in a plastic bag and seal it for the garbage.
This is heart-breaking to do because of the loss of blooms but it is a decently effective way to control gall midge infestations. Due diligence every year will keep the gall midge (Contarinia quinquenotata) population under control…and perhaps even eradicate it. But only if your neighbours practice due diligence on their daylilies as well.
There is a photo of a badly deformed bud on my website: [https://duchessofdirt.ca/hemerocallis-beauty-for-a-day/]. Also some information about the gall midge: [https://duchessofdirt.ca/contarinia-quinquenotata/].