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Neem oil causing mould

Hello,
In an attempt to curb my mealy bug infestation in the soil of my peace lilly, I started mixing 1-5 drops of neem oil in water to water the plant with but it has seemed to cause mould where the roots are. I started using neem oil because of how great its meant to be but the problem is that I can only find applications of the oil in spray form on the foliage when my problem is that the bugs are inside the soil but there isn't a lot of online advice on using neem oil for the soil. I just used some hydrogen peroxide to get rid of the immediate mould that was growing but I also found that it brought out a lot of the mealy bugs onto the plant dish which I then dispose of by washing them off. I already tried using just hydrogen peroxide last year but to no avail. Should I be combining neem and hydrogen peroxide? I'm stumped with what to do and honestly I'm surprised that my peace lilly is looking as healthy as it is considering the severity of the infestation and all the failed experiments I have done to it to try and get rid of the bugs. That's why I came here to ask for any advice and would be grateful if someone could point me in the right direction. Also I am only saying that they are mealy bugs because I hear they are white, tiny and grow into tiny flies. I have also seen tiny white clumps of balls which I believe to be eggs but again I could be wrong. I keep the surface of the soil as dry as I can, applying diatomaceous earth on the surface to prevent any further infestation so I only water from the bottom (hence why the bugs are reciding at the bottom). I hope this stream of consciousness makes sense because I honestly don't know what else to do and I need to get it out there ASAP before I re-consdier actually posting this.

Thanks, 

Posts

  • DovefromaboveDovefromabove Central Norfolk UKPosts: 79,204
    Sounds more as if they’re fungus gnats. Leave off the neem oil and top the compost with a layer of horticultural grit (or the sort sold for aquariums will do.  This stops the flies laying their eggs in the compost. 

    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh







  • Pete.8Pete.8 Billericay, EssexPosts: 9,045
    edited May 2020
    Neem oil is for spraying onto the foliage only. It's not suitable to use it in the compost as an oily film will build up which may be where your fungus is coming from and will not be good for your plant.
    Neem oil is to stop insects that suck on leaves - the oil 'glues' them in place and (in theory) they die. I've never used it but have read good things about it.
    Dove's advice above should do the trick, a good layer of grit on top and they'll soon be gone.
    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • strelitzia32strelitzia32 Posts: 767
    And for interest, it's better to mix neem oil with horticultural soap and warm water, so it actually sprays. If you try and mix just water and neem oil, it generally just separates...
  • Sounds more as if they’re fungus gnats. Leave off the neem oil and top the compost with a layer of horticultural grit (or the sort sold for aquariums will do.  This stops the flies laying their eggs in the compost. 

    Thanks a lot for the advice. I will definitely look into buying that grit. Just out of interest though do you (or anyone else) have any opinions on using the diatomaceous earth in the meantime as it is what I have on hand right now.

    Cheers, 
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