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sciarid fly larvae, please help

I need advice on what to do about tiny little larvae in the compost of my bottlebrush newly germinated seedlings and yet to germinate seeds. Should I try to move the seedlings before their roots get eaten? They are so miniscule and only have their 2 germination leaves yet but I'm thinking I'll lose them if they remain in that compost. I remove and squash any larvae I find on the top. I also have miniscule kalmia (mountain laurel) seeds that I've probably sown at the wrong time of year but I'm worried those seeds will be devoured too. Would nematode control be effective with seedlings watered from below?


  • karen paulkaren paul Posts: 230

    On further inspection I have found dozens of the little blighters on the outside of the cardboard pots that my seeds are planted in and so I've picked them off to squash them. Could it be a saving grace that they've preferred to munch the damp cardboard or could it be that they're just on their way in? I've delicately looked just under the compost surface and couldn't see any. I'm clutching tightly at straws that they've favoured the pot to eat! Also is this preventable somehow, as the flies are very small?

  • treehugger80treehugger80 Posts: 1,923

    water from below as the larvae like damp compost to live in and the flies like damp compost to lay eggs in, a layer of compost cover (grit/perlite/vermiculite) helps as well.

    if it gets bad I submerge everything (plants and compost) in water for an hour or so - this should do any major damage to the plants but drowns the larvae

  • karen paulkaren paul Posts: 230

    Thankyou treehugger, I have been watering from below as the seeds are quite dust like and the seedlings prone to damping off. I will certainly try the drowning method as you suggest if needed.   think I inadvertently killed a fly in the act of laying eggs earlier, I had sprayed fly spray to get a bluebottle (not sure if it will harm d seedlings if spray lands on them but I hate the dirty buzzing beasties r especially when I'm eating my lunch!)

  • LeifUKLeifUK Posts: 573

    Good advice above. I also dust the soil surface with pyrethrin powder, so when the flies lay eggs, or emerge from the soil, they die.

  • karen paulkaren paul Posts: 230

    That sounds like a good idea too LeifUK. I haven't had any sightings today after keeping vigilant yesterday but I may try the powder as a preventative measure for a re occurance or eggs t yet to emerge. Thankyou.

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