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Help with False Spider Mites

Discussion in 'Issues, Disease and Pests' started by ryan248, Aug 20, 2023.

  1. ryan248

    ryan248 Well-Known Member

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    Having a really bad infestation with false spider mites on several orchids in a certain area of my grow tent. I've cleaned up the area and such. I have bought predatory mites, Phytoseiulus persimilis, and I do not see any positive change. I've done weekly releases up to this point, totaling up to over 14k potential mites... making up of different stages. They are alive since I can see the adult ones that are red and are much bigger than false spider mites.

    I did put in an order for Stethorus punctillum since this species will not directly bother P. persimilis.
     
  2. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Are you avoiding using a miticide? The only mites I have a problem with are the false spider mite. A while back I looked into predatory mites, but never followed through. I did a quick search just now on the two you have mention and neither say they are for false spider mites. I can't find the website I was looking at before, but they did have one for false spider mite. Both Avid and Forbid are translaminar and very effective against false spider mite which can devastate collections of pleurothallids and defoliate Dendrobium cuthbertsonii in short order. Very few miticides are effective against them.
     
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  3. ryan248

    ryan248 Well-Known Member

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    I was at first since I wanted to avoid any kind of leaf burn. I really wanted to go the predator route but it seems that only four species go after the family of Tenuipalpidae and they barely do anything as is. It is most likely a species of Brevipalpus since the destruction looks exactly like pictures I have seen on google. Not to mention zero webbing and move extremely slow or not at all. Even wiping them off with a wet napkin ends with just red streaks. I feel like the mites are everywhere and not just on the current effect orchids... I'll attach a picture. It's not super focused but it's what the bad areas look like on all the leaves.
     
  4. ryan248

    ryan248 Well-Known Member

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    20230820_170245.jpg
     
  5. W. Malewa

    W. Malewa Active Member

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    Maybe to try organo silicones? Though this is the first time I hear about False Spider Mites, organo silicones kill many small insects and spiders. They work as a contact ai, crop and creatures need to stay wet for at least half an hour after spraying, above 25 degrees C, or 77F, and with quick drying up they can be harsh for the crop. Also eggs have too low a metabolism to be killed by the stuff, so a minimum of 2 rounds need to be done.
     
  6. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Ryan, I have used both Avid and Forbid at the recommended strengths many times on the whole collection and had no problems. I spray in the evening so avoid any high temperatures. I was told that what I have is Brevipalpus californicus.
     
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  7. W. Malewa

    W. Malewa Active Member

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    Marni, sure there can be no discussion about the efficacy of abermectin (Avid), specifically when used for the first few times control is excellent, from past personal experience and see also: Abamectin (Ref: MK 936)
    Only, despite that it is a kind of biopesticide, it is also a WHO 1b substance. So, if one is not keen on going the full PPE way etc, and biological control is not successful, then organo silicones are less drastic from an application point of view. Have you ever used them?
     
  8. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    I've never heard of organosilcones. And don't know what products they are in. From what I could find easily on Google they sound as if they are used with insecticides. Perhaps as a wetting agent or spreader/sticker? Then they are mentioned to act like a pyrethroid. Are there some product names that you know that I might be able to look up? I want a translaminar spray because my collection is very dense and getting a direct hit is really hard.

    I rotate Avid with Forbid for less likelihood of resistance. I use it when I start seeing the characteristic spotting on Dracula leaves and that could be twice a year, but less often. When I spray the greenhouses, I always wear a full Tyvek suit that covers my shoes and head and a good quality double cartridge respirator. I like the Avid/Forbid rotation because I want a translaminar spray. My collection is very dense and getting a direct hit is really hard.
     
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  9. W. Malewa

    W. Malewa Active Member

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    Also from my knowledge there is nothing wrong with the Avid/Forbid (IRAC 6/23) rotation, and systemic / translaminar properties make life easier in dense vegetation.

    Initially organosilicones (e.g. Silwet is a well known one) were indeed mostly used as a wetter, as they dramatically lower the surface tension of water. Because of that low surface tension the spray liquid can now completely engulf small insects / spiders without them having air bubbles (in their hairs), maybe even penetrating into the trachea. Whatever, practically I assume that the target pest has to stay wet for 30 minutes and then many of them have indeed suffocated, see also here in the article 96 to 97% efficacy: Toxicity and Control Efficacy of an Organosilicone to the Two-Spotted Spider Mite Tetranychus urticae and Its Crop Hosts In the article they also mention phytotoxicity, and I have seen cases of it, but mostly in relation to high temperatures and/or drying up too quickly. But e.g. wetting the greenhouse floor directly before applying reduces phytotoxicity. As the mode of action is a rather physical one, no cases of resistance. There is a small label complication in certain jurisdictions; you still have to apply it as a wetter.
     
  10. ryan248

    ryan248 Well-Known Member

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    I did a bit more research on flat mites. Apparently owners of Hoyas now get a horrible infestations of flat mites and use wettable sulfur which usually works 1-3 times. I know that Orchids are not Hoyas and are a bit more sensitive, but I want to see for myself of the results. I dipped the entire plant to the first part of the spag. moss or bark into the solution. All of them are in their quarantine box. It's a cheap route for me since I'm limited on funds atm. The only ones I don't want to toss out are the two bulbos... their common species but I've had them for so long and they're huge. But I am keeping Avid in mind. The other one I cannot order to my address/state so perhaps it's a restriction thing. I'll post results next month.
     
  11. Roberta

    Roberta Active Member

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    I have ordered from DoMyOwnPestControl Do It Yourself Pest Control Products & Supplies | Do My Own , got something, don't recall what, that said that it couldn't be shipped to California. That's my address and it showed up at my door. So worth a try... Things are not always what they seem.
     
  12. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Please let us know how it works.
     
  13. ryan248

    ryan248 Well-Known Member

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    Group A: dipped orchids into sulfur solution. 24 hours later and leaf burn at all. No scrubbing during this process. The false spider mites on these are not responding anymore.

    Group B: Rinsed off orchids real good. Then did a slurry paste instead of a dip. Scrubbed all over orchids with soft toothbrush to get everywhere. 12 hours later and no leaf burn at all. This process left more sulfur residue. Honestly like this way better...

    Only thing I am concerned about are any left over eggs. Not so much on the plants, but on/in the media?
     
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  14. Ray

    Ray Orchid Iconoclast Supporting Member

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    Consider Azamax or OrganiShield.

    The former is a concentrated form of azadirachtin, the active ingredient in neem oil, without the pitfalls of oils. It affects insects and mites, including juveniles and eggs.

    OrganiShield is the new name for the old SucraShield. Instead of being a toxin, it is a sucrose octanoate "super surfactant" that strips protective layers off soft-bodied insects and mites, their eggs and juveniles, resulting in suffocation and desiccation.
     
    Last edited: Aug 24, 2023
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  15. ryan248

    ryan248 Well-Known Member

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    Two pictures of these damn things. I bought a digital microscope that connects to my phone. It's cheap, but at least I can see the smaller ones and the eggs. Finding a lot of eggs even after brushing off with a toothbrush. They really get in the cracks and such. Literally having a meltdown...I am not buying anymore orchids, let alone bringing anything new in. This is just insane! Screenshot_20230824_140941_Max-see.jpg Screenshot_20230824_141135_Max-see.jpg
     
  16. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    When faced with a problem like this, I ask myself: Who is smarter, me or the mites? The insecticides that used to get everything on the first try are no longer sold. It may take a few tries to get it under control. If you've gotten this far with orchids, you aren't likely to give up easily. Great images!
     
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  17. ryan248

    ryan248 Well-Known Member

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    I looked into OrganiShield more. Just ordered the trial size to make a gallon spray. Hoping it does the job!
     
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  18. ryan248

    ryan248 Well-Known Member

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    Screen_Recording_20230824_223022_Max-see

    Here's a short video of the mite if anyone wants to guess the species. The link expires in two days. I tried to embed/upload here but it is not letting me...
     
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  19. ryan248

    ryan248 Well-Known Member

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    Just drenched the orchids that were the worst with organishield. It says it's very safe but still wore PPE. I used 100ml and going to do the 100ml for the next 3 days, but every other day. Won't be able to spray at my new place. Doing most of my collection tomorrow. Hopefully this all works out! I think the most expensive thing out of this was buying heavy duty clear totes. I wanted to isolote everything before I moved. I'm even buying a new grow tent just to avoid any stragglers. I still have a bunch of old LED lights from my terrariums that I can still put over the totes. Only thing I don't have going is air flow... may put some of my old usb fans in there.