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Treating Spyder Mites In GH.....

January 10, 2019

Need some suggestions for treating my small GH for spider mites. I left it closed up all last summer, it was hot enough to melt trays & inserts so I'm wondering if that much heat would kill mites? Heat is one way bed bugs are eradicated but mites are some tough bugs.... Would spraying a 10% bleach solution help?

Comments (11)

  • mindshift

    I have an enclosed porch rather than a greenhouse, but it's where I keep my tender plants over the winter. I used to have some lei plants that were healthy until I brought them indoors. Almost as soon as they were brought in spider mites would show up. It turns out the the lei plant (aka frangipani) is a favorite of spider mites. IMO, the spider mites had been on my plants the entire growing season, but natural predator insects kept them at bay. Bringing the plants inside gave the mites a warm, dry, predator-free environment. There are several types of spider mites in colors of red, green, yellow and brown. Spider mites with spots on their backs are especially resistant to control even by pesticides.

    Before bringing any plants in from outside, give them a shower. Use a spray nozzle on your garden hose to wash the top and bottom of your plants leaves. Let the plants dry, then spray them thoroughly with neem oil, soaking the top of the potting soil also. Cinnamite (derived from cinnamon oil) and rosemary oil mixed with water are also effective miticides. There are also many commercially produced natural PRODUCTS. Keep an eye open for return infestation when using organic methods because mite eggs will continue to hatch. It's best to repeat the organic pesticide every three days for two weeks. I'm not going to discuss the hard-core pesticides because they are extremely hazardous.

    gltrap54 thanked mindshift
  • gltrap54

    Thanks mindshift for your input! I will give your suggestions a try. Unfortunately, my infestation is that of the Two Spotted spider mite, so I've got my work all cut out for me...

  • rob333 (zone 7a)

    Getting rid of the plants is all that worked for me, so I hope you solve your problem! I thought, just one little lavender plant won't hurt, will it? Yep, started it all over again in another place in the yard. Oy.

    gltrap54 thanked rob333 (zone 7a)
  • ken_adrian Adrian MI cold Z5

    as i understand.. the house is completely empty ... but for some melted plastics.. lol ...

    now is the time to go full hardcore nuclear war ... so it will be 'clean' come spring .... or late winter ... and i dont call 10% bleach ... 'war' ... thats more of a clean the kitchen floor thing ....

    you might find a good source of info.;. at your local county extension office .... sounds like it might be a regional issue they are aware of ...


    gltrap54 thanked ken_adrian Adrian MI cold Z5
  • gltrap54

    Yeah Ken the GH is currently empty.... Went to my county extension office for their help & by doing so I shot myself in the foot..... Yes, they (the extension) tried to be helpful & did identify the two spotted spider mites, but it wasn't long before I was being paid a visit by the state ag inspector due to the fact it's the extension's job (apparently) to report such incidents.... The inspector wouldn't say why they had came to my home other than to say it was just a "routine" inspection.... Now I'm sure the extension is required to report these incidents but I felt like they were pouring salt in open wounds, given the fact 90% of my annual flower production had been decimated after months of investing time & money...

  • zen_man

    Did the inspector tell you the results of his inspection?

    As you mentioned in your original post, Professional Pest Controllers do get rid of Bed Bug infestations by having people leave the location for 24 hours or more while they raise the temperature in the place. Since your Green House is empty, you could do a similar thing -- the questions being how hot and for how long. Probably the most difficult thing to kill is the eggs of the Spider Mites. Maybe that inspector guy could provide that info.

    Incidentally, the two times that my indoor zinnia project experienced Spider Mites, the Spider Mites won. In both cases I had brought some zinnia cuttings in from outdoors. I don't bring any outdoor zinnia material in now, and so far, knock on wood, I haven't had another Spider Mite episode. They say that prevention is the best cure. After my two Spider Mite episodes, it may be the only feasible or affordable cure. I have since learned that there are some expensive systemic miticides, but I have not had an occasion to try them.

    gltrap54 thanked zen_man
  • gltrap54

    I agree that bringing outside plants inside is a prime source for infestation... My GH was left closed up the entire summer & was hot enough to melt plastic, but I'm told the TSSM is the toughest of them all.. I know chemical treatment steps on many folks toes, but I'm willing to try most anything to avoid a second crop failure.. I purchased Kontos miticide last year but found it ineffective... Strange thing about Kontos is it's designed to work in the GH but not in your outdoor garden... I can't wrap my head around that one... Very expensive also... Also plan to fog my now empty GH with Pylon as soon as it warms up a bit..

  • zen_man

    Hi gltrap,

    I'm not sure Pylon was meant to fog an empty greenhouse. The info I saw indicated it was for spraying on living plants. Also, it has a phtotoxicity problem with some plants. I saw this warning on one website:

    " PHYTOTOXICITY IS LIKELY TO OCCUR to some varieties of:carnations, dianthus, kalanchoe, poinsettia, roses, salvia and zinnia and applications to these species will be made at grower risk. "

    That call-out for zinnias eliminates it as something I will use. Also, the fact that Pylon is not ovicidal suggests that it is not going to be a big help in your empty greenhouse, where killing the eggs is currently your main problem.

    I think your best course of action is to artificially heat your greenhouse using your existing heater to a high temperature for at least 24 hours. And hopefully not burn your greenhouse down.


  • gltrap54

    Hmmmm ZM...…. I may have to rethink using the Pylon although I'm sure the canister I have is Pylon TR (2 oz. canister,total release)….

    Here's an excerpt from Do My Own pest control : Pylon TR Total Release Insecticide is the first insecticide of BASF to deliver active ingredients by using total release (TR) technology. Pylon TR Total Release Insecticide contains the active ingredient, chlorfenapyr, that is easy and ready to use and comes in small canisters. It provides widespread control of mites and thrips. It is for the use in closed commercial greenhouses on flowering hanging baskets, bedding plants, potted flowering plants and ornamentals, cut flowers, foliage and fruiting vegetables. Growers will have the ease of use by just placing the can in the greenhouse, closing the vents, doors and windows and pressing the release button and leaving it for a specific time. Two ounces of Plyon TR Total Release Insecticide is able to treat 3,000 square footage of a commercial greenhouse....

  • zen_man

    Hi gltrap,

    Obviously that Total Release can will "work" in an empty greenhouse, but I still think they were thinking of a greenhouse full of plants, rather than an empty one. But I could be wrong. Right now your spider mites are eggs, and that Pylon TR won't kill them.

    At this point I would be thinking are there any things still in your greenhouse that might be harboring the TSSM eggs, and can you remove those things and send them to the trash dump landfill?

    I have a small bottle of Kontos that I got to use on my next spider mite outbreak, and I am not extremely surprised that you found Kontos to be ineffective. Oh well. I can confirm that Liquid Lady Bug is worthless against them.

    Hopefully somebody will come up with a solution for the Spider Mite problem. Maybe some kind of out-of-the-box thinking that amounts to a "hack". They are in the animal kingdom, sort of, and have to breathe oxygen, and your plants aren't animals, and don't need oxygen. So maybe if you flooded your greenhouse with pure carbon dioxide, possibly cut with nitrogen, you could suffocate the spider mites without hurting your plants. That might not be practical, and might even be dangerous to you and others. And it probably wouldn't kill the spider mite eggs. Oh well.


  • FastInk

    Meh, I'd water with a 5% bleach solution if need be. Ideally keep humidy down and watering to a min untill it passes. Soapy water spray works great. Not sure if spraying bleach into the air would do anything.

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