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Extreme scale insect infestation: what would kill these buggers?!

I just noticed my 15 year old tropical hibiscus tree is loaded. It spends summer out on the deck, and winter indoors.

When I see scale on other plants, I wipe them off with a wet paper towel, then spray weekly with Neem oil.

But this poor plant is loaded. Hibiscus seem to get them every year.

Is there an alternative? It would take hours to wipe these things off of every stem.

Long ago I vaguely remember something about spraying with fish emulsion mixed with something.

Thanks for your help.

Comments (10)

  • last year


    It's so sorry to see this creatures on your plants.

    Here is what I would do:

    Buy some serious systematic insecticide.

    Mix it with water in a ratio like 5-10g/10L water and water the soil 2x in 30 days.

    That would kill this nasty creatures.

    After they are killed and dried out you can wash the plant with a stream of water.

    That would I do in your case.

    And I did it many times when I have invasion of that staff.

    Take care with poisons!!!!

    Always deal with them carefully and outdoor.

    linnea56 (zone 5b Chicago) thanked Christian Robert Adzic
  • last year

    you mix ANYTHING.. according to the label .. period..

    i treat all my indoor winter houseplants with a systemic product in early sept.. OUTSIDE.. so when i have to take them indoors in early october.. they come in 'clean' ...

    find a product that is labeled for such .. including scale ...

    this is the time of year.. plants are storing energy for next season.. so treat them soon.. else you are sucking next years growth out of them ...

    can you come up any any simple normal problems... lol .. its always something in your garden .. lol ..


    btw.. even if they die.. they wont fall off.. so they will still be there.. unless you pick them off anyway ..

    linnea56 (zone 5b Chicago) thanked ken_adrian Adrian MI cold Z5
  • last year

    Thanks, Christian and Ken. What systemic would either of you recommend?

    Good point, Ken that even after they die they'll still be glued on.

    When I've had them on other plants before, I've always wiped / scraped them off with a wet paper towel, then sprayed with Neem oil or something weekly. When I saw these, I was dismayed. There are just so many! This branch in the photo is nothing. I don't know how I failed to see these. It will take a long time to wipe all of them off : at least a systemic can start the work, and if I miss some they won't be repopulating. .

    They are usually brown when I see them. These are black. I don't know if that means they are a different sub-species? Not that it matters.

    I know, Ken - DO I ever have simple normal gardening problems? What ARE simple normal problems? In my non-gardening projects, I don't have simple normal problems either.

  • last year

    "What systemic would either of you recommend?"

    Most systemic products recommended for houseplants contain imidacloprid. While it is of little concern when using with houseplants, I'd avoid using it on any outdoor plants, especially flowering ones, as it can be toxic to honeybees.

    Follow the directions carefully and reapply as needed but always within label guidelines.

    linnea56 (zone 5b Chicago) thanked gardengal48 (PNW Z8/9)
  • last year

    not sure how helpful this is, but i managed to curb an aphid infestation on my bell peppers with soapy water. read online that it just melts the lil buggers as you wipe them off and again it seemed to work. not sure what these creatures are but hope that can be of some help

  • last year

    I’m afraid that scale are a different order of difficulty from aphids. Soapy water will not touch them due to their tough shells. Even contact insecticides won’t affect them. I’ve successfully treated a badly infested lemon tree with baby wipes, as recommended to me by a specialist citrus grower. But it took a long session just sitting with the plant on a table and firmly wiping every leaf and stem.

  • last year

    A squirt bottle with straight rubbing alcohol will get rid of them but test a part of the plant before spraying the entire plant for sensitivity. I use this on Sansevieria and other succulents with good success.

    This link recommends a cup of alcohol, a tablespoon of insecticidal soap, and a quart of water for spraying heavy infestations of scale on plants.

  • last year

    i have granules from about 30 years ago.. lol ... still using them up.. they stink .. ergo.. they are applied outside a few weeks before ringing the plants in ... it gets rid of everything in the pots... worms.. ants.. gnats ... etc ..

    the ONLY time oil works on scale.. is that few days in spring.. when babes crawl out from under momma.. and move along the branch to a new spot.. otherwise.. you are wasting oil.. and your time...

    btw .. as to your title.. no way.. ive seen extreme.. where you coudlnt see any plant material.. just all scale ... that was extreme ...

    im thinking its not your actual problems.. but your prose that makes all your issues seem so intense ... ever consider writing a novel .. some plant detective ????


    linnea56 (zone 5b Chicago) thanked ken_adrian Adrian MI cold Z5
  • last year

    Ken, I am writing a novel! Not plant related. But some pretty intense disasters....It's been in the works for a number of years. 300 pages down.