Garden Pests---White Fly

Discussion in 'Plant Pests, Diseases and Weeds' started by Sjoerd, Oct 20, 2016.

  1. Sjoerd

    Sjoerd Mighty Oak

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    White flies...a real and pernicious pest on our lotties here, but what are they? How do you recognize them? Finally, what can be done?

    White fly sorts fall under three groups: Aleyrodinae, Aleurodicinae and Udamoselinae. These sorts get onto a number of different plants, but they are very interested in brassicas...and the type known as Aleyrodes proletella is the white fly type with which I will focus on here today.

    For those who do not know this pest—it is a small flying insect about 1.5 mm long. Its wings are covered with a white, waxy powder. It is larger than the white fly that one finds in greenhouses. Its wings have four light grey, almost imperceptible spots on them.

    The Pest
    The larvae of the white fly are laid in a circle, (usually) on the underside of the brassica leaves. It is important to note here that the Aleyrodes proletella almost exclusively infest three specific sorts of brassica—the Brussels Sprouts, Savoy Cabbage and Kale. The larvae and pupae have a thick layer wax over them. It is common to see the insect in all three stages.

    Damage

    The white flies expel honeydew which makes the leaves sticky and dirty. Fungi can colonize and under this condition. The flies bore into the phloem for nourishment. Their saliva is mixed-in and the plants react to this toxic substance whereby the leaves loose their turgor and become flaccid. The leaves will eventually; one for one, turn yellow and fall off the plant.

    Life Cycle
    The female adults lay technically living larvae (some folks refer to these as ‘eggs’). They can lay up to 200 at a time. At any rate, the larvae eventually come out of this stage and sort of wander over the leaf for a couple of hours, looking for a place where they can begin sucking phloem.

    When they shed their first skin, they anchor themselves and will serious feeding. At one point, it will be time to pupate in this same place. An entire cycle will last from twenty to forty days, depending on the temp.

    The bad news here is that white flies over-winter on living green plants. It is such a shame for those of us who want to harvest veg throughout the winter months. Well, it is what is is, and so we must take steps to protect our crops.

    What To Do
    --Obviously, you want to get rid of as many green plants as possible in your garden to limit the overwintering possibilities for the flies. Sadly there are other plants like, strawberries, azalia’s and rodi’s where they will set up shop.

    --Pyrethrum is widely used and is effective. It does kill other types of insects though.
    --Green soap with or without spiritus.

    --Check the tops of the plants frequently and remove leaves with colonies.

    --Use a very fine gauze over your plants.

    --Use white flies’ natural enemies such as the Encarsia formosa. One can order these commercially.

    --You can use those rolls sticky of flypaper like you use for flies in your home, which will attract and stick them.

    --I have even heard of folks using a Hoover/ vacuum cleaner or a small one like you suck up ashes or cookie crumbs off the salon table.

    --One can also simply use water that spurts hard out of a hose or sprayer to irrigate them off the plants. I have done this as well as used soapy water.

    --I also go to the lottie on a cold and windy winters' day and shake each plant...they fly up and the wind blows them away.

    The key to success is to keep treating them. You have to do this because unlike aphids they have various stages of development, and if you spray; for example, you may kill those present at that moment, but later pupae and larvae will hatch out of their old stage and emerge unscathed to continue their life cycle.

    Now, a few images:
    To begin with let me introduce my chalky friend:
    vlieg5.jpg

    You should check your brassica's frequently, especially the leaves in the top of the plant. You can see on this picture and others, the white area in contrast to the dark green of the leaf perimeter/tip. That is the web "blanket" that goes over and protects the larvae.
    vlieg4.jpg

    The top or bottom of the leaves is where they can be found in their communities. In this foto you can see the beasts in the three stages of their life cycle. Again the protective white net is visible.
    vlieg2.jpg

    Finally, after spouting them with a hard stream of plain water you can see these peculiar balls of water mystically coated with the tiny particles of the white waxy powder of the wings of the white flies. Amazing stuff.
    vlieg.jpg

    I couldn't believe my eyes the first time I saw this phenomenon. It looks like some kind of bizarre, if not harmful chemical.

    I hope that you guys do not get this pest, but if you do--something can be done. Just don't give up.
     
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  2. 2ofus

    2ofus Young Pine

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    After reading your post I looked White Flies for Idaho. It seems that they are here but, if they appear, it is normally in greenhouses. We will keep an eye out for them thanks to your post.
     
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  3. Tacticalgardener

    Tacticalgardener Seedling

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    They are a huge problem here in South Florida where it rarely gets cold enough during the "winter" to kill them. Neem oil works really good on them, but it takes some time to work. Those of us who live in regions where they are a big problem will find that it helps tremendously if you start treating your plants (they love peppers and tomatoes) with neem while they are still young and before the whiteflies appear on our plants. If you wait until you see colonies on your plants, you are already way behind in that battle. Whiteflies also spread disease like tomato yellow leaf curl, which is devastating to tomatoes.
     
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  4. kate

    kate In Flower

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    I wonder now if thats what I have had since last year. They came out of nowhere.
    They look like a small moth, if I am in the garden I have to keep smacking them one. Water hosing does not deter these pests.

    Something probably them have stripped branches on my Korean Fir tree.
    :frustrated::smt092

    K
     
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  5. Sjoerd

    Sjoerd Mighty Oak

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    Hello 2OF--I see. Well, that would be one of the other types. They can also be harmful to your plants. Fingers crossed that they will stay out of your garden and greenhouse.

    Lets hope that they stay out of your garden, TACT.

    It could be KATE--I know that Britain has several types. These things do look like small moths....VERY small moths. I do not suspect that they were the culprits on your Fir tree, because their larvae do not strip, they suck.
    I do wonder what you have though. I would love to see a piccy if you can take one.
     
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  6. KK Ng

    KK Ng Hardy Maple

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    Looking at your photos makes me want to squeeze them.

    I get this white flies regularly on my egg plants, tomatoes, sweet potatoes and chilies. In this part of the world they attack the plants from underneath the leaves. What I do is to inspect the leaves one by one for eggs and if there are eggs I'll use a toothbrush to brush them away, making sure the do not drop on the leaves below. After the brushing a bath of soap water. It is time consuming but I find it the most effective way at the moment.

    If there are flies colony, I'll gently fold the leave and squeeze it hard to kill them before removing the leave from the plant.
     
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  7. Sjoerd

    Sjoerd Mighty Oak

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    Sorry to hear that you get white flies there as well. It sounds like you have a good technique for combating them.
     
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  8. kate

    kate In Flower

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    Sjoerd, I have the pain of my Antivirus running and lunch, and then I had a woman call because they want last minute details for the walk in shower the council are installing in all bungalows.

    So clearly 'some pest' is at work. I have sprayed a few times with Pravado our main bug killer for all but its slow getting my needles growing again.

    [​IMG]

    K
     
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  9. Sjoerd

    Sjoerd Mighty Oak

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    Kate, I can't see anything specific that would alert me to this, that or the other pest. My mind was wandering and I wondered if you had perhaps let that tree become too dry at some point. It seems unlikely, but possible I suppose. The new growth at the tip of the branch would make me think that the moisture level would now be back to an acceptable level.


    It is the fact that the problem occurred at the distal end of the branch...of course it could also be something that likes feeding on young, fresh growth.

    If you illuminate the "sick" areas with a torch can you see any webbing like spider mites might make? Sometimes it helps to investigate at the micro level...with loop and light.

    I hope that you get an answer on this frustrating problem.
     
  10. kate

    kate In Flower

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    Its ok Sjoerd: A forum I go to there is a great tree/plant guy and may be able to I.D for sure.
    It got plenty of water every other day. I think they survive in higher/colder/ dryish altitudes with just air moisture. Another problem could be these gardens are not so deep.

    I recall last year when I worried about the tree full of snow and he set my mind at rest that they are survivors in the coldest of gardens. I really love this tree and plan to buy another Fir next season. The bugs will have gone now, the leaves will slowly return for next Springs bugs.........:smt043

    Thanks Sjoerd!!
    K
     
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  11. Sjoerd

    Sjoerd Mighty Oak

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    You are most certainly welcome, Kate.....but I do not think that I actually helped much. I hope that you can get some good "on site" help there next season though. Fingers crossed forya, meid.
    The seed catalogues ought to be coming in soon....Do you look through those during the winter?
    I have got to clean the edges of my canals VERY soon, so I shall continue working in the lottie for some time.
     
  12. kate

    kate In Flower

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    Thanks sjoerd!
    Plant books: not really buy from them more look in the local knock down price shelf in my local DIY store, I can get them sometimes for a £1.00 each. I can buy Violas a tray of 12 for £2.99.
    I bought my Fritilareas from online, huge bulbs. They cost me £15.00
    Two plants I would like next year are another Fir tree and a Fern.
    K
     
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