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Greenhouse Pests

I have been in my greenhouse today only to find that I have Whitefly and Greenfly on some of the plants. Can anybody recommend a fumigator that I can use with the plants left in the greenhouse. I have looked at some on the internet but they tell you to remove your plants which seems to me a waste of time as the pests are on the plants.


  • I don't bother with chemicals, as they kill the good insects too.  The idea is to let nature take it's course, the birds may fly in to eat the aphids and so will the bees and wasps etc., so killing them has a negative effect on the nature chain

    Firstly I try squashing the aphids between my fingers a few times.

    If the aphids persist than I spray the remaining aphids with water a few times over a period of a week or two.  If the aphids are still causing a problem then I spray diluted washing up liquid.  Not many aphids survive this routine in my greenhouse.

    I hope this helps.

  • There used to be a product which you could use just as you describe.  I've a feeling they were a type of sulphur candle which you lit and left to burn for several hours ( presumably the "length" of the candle.  Doors and vents closed and leave 24 hours.

    It's such a long time since I used them that I have no idea of name or actual makeup or actually even how effective they were - sorry.

    I think the greenfly are easier to deal with - squishable by hand and water spray but the Whitefly can be a pain.  

  • LynLyn DevonPosts: 16,565

    I have all my Fuchsia cuttings indoors, they live in conservatory for the winter, they are covered in white fly I’ve tried all the bug sprays on the market, chemical and ‘green’, I’ve even resorted to house fly killer,  nothing works, I think you can buy nematodes for them if you haven’t got too many Plants.

    what I do is go through the plants every couple of days and squash, they are very obliging, they just sit still whilst you squash them. 

    Gardening on the wild, windy west side of Dartmoor. 

  • Lyn

    Thanks for your reply Lyn I might have to resort to this myself 

  • PosyPosy Isle of Wight.Posts: 2,121

    What about those sticky bits of card that you hang up? Do they work? You would need to encourage the little beasts to take flight but that isn't difficult.

  • I have heard of these somewhere before but completely forgotten about them. All I need to do is see if I can find who sells them. Thanks Posy

  • LynLyn DevonPosts: 16,565

    Those sticky things didn’t work, they just caught a few flies and bees, wouldn’t use them.

    Gardening on the wild, windy west side of Dartmoor. 

  • Install a power fan. Most insect pests thrive on stagnant, damp conditions - November in England, The fan will desiccate them and reduce their number by 90%. Just as wind would if they were growing outdoors. Other solutions ie. insect predators are more appropriate for summer. Good luck. Ian

  • LynLyn DevonPosts: 16,565

    I thought white fly preferred dry conditions, my conservatory is part of my kitchen, warm and dry like the rest of the house.

    smokes are no good for whitefly, you have to take all your plants out of the greenhouse before you light the smoke. You‘ll just be putting them back later.

    Gardening on the wild, windy west side of Dartmoor. 

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