Phytotoxicity from Neem or Bug Bite Blister?

Discussion in 'Cacti and Succulents' started by MiniBot, Jun 18, 2005.

  1. MiniBot

    MiniBot Member

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    Location:
    Alameda, CA, USA
    Hello, this is a Rhipsalidopsis gaertneri, I've also posted at another gardening forum and one person so far thinks this damage is from the bugs, but I only saw a spider and some pock marked new growth and a very small aphid which I squished. I then decided to treat the whole plant to some neem oil spray made up one tsp. oil with one tsp. detergent and one quart warm water, shaken then sprayed on the plant. I left the plant in the window (indoors) for a day and didn't notice anything. Then the next day (yesterday) I came home to find this:

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    When I hold up the plant to the light I can see through these blisters (they appear yellow with black very thin lines in the center). What is this? I thought it was from the neem, but I'm so not sure. The plants were fairly healthy and I had brought it in from outside to enjoy the blooms. It finished blooming and I disbudded all dead blossoms regularly. Then I saw pock marks and an aphid and decided to spray...two days later the above damage. Any guesses or exact diagnoses? I'm stumped.

    minibot
     
  2. growest

    growest Active Member 10 Years

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    Location:
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    minibot--are the blisters on the "sun" side of the plant only, or both?

    I have had a fair bit of leaf damage on things using neem, esp. if the plants are a bit stressed for water. The leaf burn is much amplified by direct sun.

    I suppose some plants may even be "allergic" to the oiliness of the neem, similar to some plants that react negatively to dormant oil sprays. I found my hebe's, for e.g., are almost always damaged by neem.

    I like the systemic action of neem, but for simple things like aphids I have gone back to using "trounce" (insecticidal soap) whenever possible.

    Glen
     
  3. MiniBot

    MiniBot Member

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    Unfortunately they are on both sides (I thought maybe it heated up through the plant?). It is certainly ugly. I guess I'm just looking for the reason so that I don't repeat it. I don't want to be put off the neem oil because I hate the fact that many pesticides kill birds and beneficials. Maybe it *is* an allergic reaction to the oil. I'll certainly not be so rash next time, and I'll test a spot for a week first! Any other guesses as to what this might be are certainly welcome!

    Minibot
     
  4. MiniBot

    MiniBot Member

    Messages:
    10
    Likes Received:
    0
    Location:
    Alameda, CA, USA
    Unfortunately they are on both sides (I thought maybe it heated up through the plant?). It is certainly ugly. I guess I'm just looking for the reason so that I don't repeat it. I don't want to be put off the neem oil because I hate the fact that many pesticides kill birds and beneficials. Maybe it *is* an allergic reaction to the oil. I'll certainly not be so rash next time, and I'll test a spot for a week first! Any other guesses as to what this might be are certainly welcome!

    Minibot
     

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