Hemerocallis Gall Midge

Like many other gardeners, I am busy removing hemerocallis (day lily) buds, infected with gall midge larvae, before they fall to the ground to produce a new generation.  I live in hope that if I, and neighbouring gardeners are sufficiently vigilant, it may be possible to eradicate this pest from the garden.  Certainly in this second year of action, there seem to be slightly less buds affected, if this is not wishful thinking.

I was going to ask if anyone could tell me what the lifespan of the adult midge is?  I then, after exhaustive searching, found this text on an American forum:

The adult midge has the capacity to fly 5 km in her 72 hour life span - so she is quite busy! The best form of control continues to be educating as many people as possible as to what to look for - and diligently picking off those affected buds and destroying them - burning is always best, never composting!

Eradicating a future generation will therefore lessen the numbers threatening in the following year considerably, provided that neighbours are equally vigilant and motivated.




  • BerghillBerghill Posts: 2,918

    Been doing that for the last 10 years and we still get them and no one else round here grows them either. In the end I am slowly but surely removing the plants . What is the point of a load of green leaves with no flowers?

  • Victoria SpongeVictoria Sponge WearsidePosts: 2,466
    I didn't know about this so thank you for the heads up- the buds are just emerging so I'll keep an eye on them image
  • SalinoSalino Posts: 1,609

    ..never heard of it so I shall keep an eye out... mine are in full flower...so hopefully no problems so far.. best of luck with yours in the future... hope it improves for you..

  • fidgetbonesfidgetbones Posts: 12,039
    I've never had it before ,but one of my new plants seems to have distorted buds.

    Off with their heads!!!!
    It's not a mess, it's a nature reserve.
  • The midges are only around for the early flowering hems so it may be necessary to just grow the later ones.  There is a website that gives the result of a controlled trial of treatments: water, contact pesticde, and two different systemic pesticides.  the latter two gave some improvement.  I think that I'll carefully record and mark any effected plants and make sure I spray them early, before the flower spikes appear and again as soon as they do.  It's not all early plants that get hit.  My earliest (Earliana),put on a lovely display, whilst Corky, such a prolific performer in the past, looks as if all buds are infected like last year.

    This is war!!

  • LorrainePLorraineP Posts: 216

    My day lily plant seems to be suffering some kind of disease or pest .  I have posted a photo in the hope that you can help me identify the problem.  Does this look like gall midge?  I had initially thought it was slug damage as I caught a monster slug lounging on a bud the other night.   Grrr !! image





  • SupernoodleSupernoodle Posts: 948
    I had a similar problem with a few blooms ( young plant so weren't many anyway) so this post raised alarm bells. I'd pulled off and binned the damaged ones so can't remember exactly what they looked like but I think like Lorraine's.

    Just been out this morning and buds look ok. Pulled off the next one due to open and can't see anyone inside - would I be able to see them?

    Also the next one due after that looks to have a tiny puncture in the side - would I be able to see the hole from the fly going in or is that far too small and this hole a coincidence?
  • The buds usually form more like a ball than long and slim, when affected.  Some buds are more circular when young anyway, but lengthen when mature.  Browning or blackening of the opening flower is a bad sign as it's probably rot caused by bug entry or devouring.  It's essential to remove the affected buds before the rot is sufficient that the maggots fall out.

    This is what you're looking for, though numbers can be less than that shown:


    Note the maggot size shown in the last photo.  Also note the pesticide report link.I don't throw pesticides around my garden but might have to resort to that, just for these plants, if bud removal fails.  Let's face it, I'm in danger of infecting my neighbours.

  • LorrainePLorraineP Posts: 216

    I removed all the damaged buds off my plant yesterday.  On opening up some of these buds I found the tiny grubs/larve, presumably of gall midge.  Thanks for this thread, I am now enlightened and will recognised the problem if (more likely, when) it it occurs again.   I'll also be disposing of the affected buds by burning them, when I decide a suitable location for a mini bonfire.  I will also have to stop my practice of throwing dead-heads under the hedge!    image

  • Burning is one solution but another is to put the buds into a zip-lockable plastic bag and leave it in the sun.  Check daily to add newly apparent infections to the bag.  By mid July there should be no more to add and the soupy sludge in the bag should only contain corpses.  You can probably detect a hint of hatred here.

    This year I'm finding them slightly more widespread and on plants that have been clear before.  However, on all but one, most buds have been clear so far, just the odd one infected.  I have a lovely white one called Rosewood Snowflakes that seems to be particularly susceptible, but on close inspection, the problem is probably caused by little beetly bugs, so that one has been gently sprayed.

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