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Algae on leaves

Discussion in 'Issues, Disease and Pests' started by Uluwehi, Jan 19, 2011.

  1. Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

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    I've never had a problem with green algal growth on my orchid leaves until I began growing in my new controlled growing environment. When I first saw algae forming last spring, I thought "wow, how cool". After while however, I began to wonder if the algae was doing more than just hitching a ride on leaf surfaces. Despite continued algal growth, my plants seem to be growing fine, so I figured that the coating wasn't detrimental to the health of my orchids.

    At last month's San Francisco Orchid Society meeting, Marni Turkel and Judy Carney taught a great skill session on grooming and preparing plants for display at shows. It was excellent, and I was inspired to clean the algae of of the leaves of some of my plants that are in spike. Last week I picked up some 3.0% H2O2 and loaded up my sprayer. I drenched my plants in it and watched everything fizz and hiss. :D After a few minutes I sprayed water on them to wash off the dead algae, however not all of it came off. In the skill session it was recommended to wipe the surfaces of the leaves with paper towels, but most of my plants are angraecoids and I get nervous about bruising (or breaking!) the leaves because of clumsiness. Also the leaf axils are hard to clean with a paper towel or tissue.

    Yesterday I got back to working on cleaning with the leaves, this time with fine paint brushes. It takes longer, but it works very well! It's a curious feeling to be painting the leaves of one's plants, rather Zen.

    I do wish I would have cleaned the algae much sooner. A number of leaves that had thick coats of algae for 8-9 months are now mottled because they weren't able to photosynthesise properly or evenly. This mottling distracts from the aesthetic beauty of the leaves. I don't recommend procrastinating algae removal.

    Some commercial growers include diluted H2O2 in their water lines to keep algae from ever forming. In the future I may try adding a few mL to my tank each time I water.

    Apparently some Dendrobium spp., especially nigrohirsute species are sensitive to H2O2 and will defoliate when sprayed.

    I am interested in hearing how others control their algae.
     
  2. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    About an hour ago I sprayed a D formosanum to see what will happen. Thanks to Jacob for mentioning this possibility to me a few days ago. I'll let you know.
     
  3. Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

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    I look forward to hearing how your Dendrobium formosanum fares. I haven't sprayed any dendrobiums, but mine don't have algae on their leaves.

    I should mention that unless one doesn't want one's fingers to be sore, wearing gloves is a good idea :eek: The H2O2 works as a sort of chemical manicure!
     
  4. Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

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    I am just passing on Andy Phillips' knowledge :)
     
  5. mrbreeze

    mrbreeze Anglican Supporting Member

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    I use peroxide religously. I add it to soaking waters, spraying waters, misting waters, even dirt plant waters! And i have a spray nozzle that I just screw on to the bottle of H2O2, which is very convenient. I never have had any issues with algae. I mainly use the peroxide as a potential anti-fungal/anti-microbial. I don't know how well it works but it is damn cheap and readily available and breaks down to water so i figure why not?

    Oh yea, i also add it to my humidifiers.
     
  6. Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

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    Thanks Breezy!
     
  7. T. migratoris

    T. migratoris Active Member

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    Great post. I have a gunky plant sort of beneath one of the misters that I'll clean this weekend. I never considered the possiblity that the algae could affect photosynthesis.
     
  8. abaxter

    abaxter New Member

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    I'm a Physan and paper towel user and it works well for me, however, I do bend a leaf now and again.
     
  9. Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

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    Thanks T. migtatoris.

    I have found that Physan often burns root tips. Has this happened to your plants abaxter?
     
  10. Ray

    Ray Orchid Iconoclast Supporting Member

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    I also use Physan.

    A monthly (OK - 6 to 8 weeks) spraying at 1/2 tsp/gal seems to have no ill effects on anything in my collection.
     
  11. abaxter

    abaxter New Member

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    I don't use it on roots so I can't comment on that. If I need a fungicide, I use Cleary's 3336. I just dampen a paper towel with Physan and
    wipe the leaves. If you want 'em to look snazzy, use horticultural
    oil or insecticidal soap.
     
  12. Forrest

    Forrest Really Neat

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    round up. run it through a hand sprayer or an overhead waterer. No more algae.
     
  13. abaxter

    abaxter New Member

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    ...and no more plants to annoy you with algae either!
     
  14. PaphMadMan

    PaphMadMan Member

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    Some algae deposit calcium carbonate, so a little vinegar might help clean off stubborn crusty algae growth. It is easier to prevent than clean though, and I would use Physan as others have suggested. It concentrates as it dries, so I would use it as a very dilute spray.
     
  15. Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

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    Thank you PaphMadMan and abaxter, great tips!
     
  16. orchidkarma

    orchidkarma Member

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    We cannot get Physan in Sweden... but peroxide should be no problem. Anyone know if mrbreeze's peroxide cure is any good for algae? What dilution (and how often) would you use for anti-fungal/anti-microbial prevention?
     
  17. mrbreeze

    mrbreeze Anglican Supporting Member

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    The standard concentratin available here is 3%. You can use it with no dilution and I've never seen a problem. You can also pour it straight through a pot at full strength if you'd like. If you add it to water the concentration will be something less than 3%. I used math to figure that out. :D
     
  18. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    If you want it in larger quantities, it is available in higher concentrations that can be diluted. You need to be careful with the higher concentrations and wear appropriate safety gear: goggles, gloves, long sleeves, etc. It is used in the hydroponic industry to oxygenate water. I use an on line dilution calculator to figure out the rates to get a particular concentration. Of course, if I had MrB on speed dial I wouldn't need the internet.
     
  19. Dale

    Dale New Member

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    "if I had MrB on speed dial I wouldn't need the internet."
     
  20. orchidkarma

    orchidkarma Member

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    Thanks for the info! :) For preventative measures, how often do you spray with the full 3% concentration?

    :D :D :D