Spider mites on pleurothallids and other minis; treatments?
 

Okay, so recently I have acquired some micro miniature pleurothllids that I am growing in glass orb terraria near a window in my apartment.

Through this past fall, winter and spring I kept some houseplants in the apartment, all of which acquired severe spider mite infections while indoors. All of the survivors are now on my screened porch but the spider mite issue seems even worse on the porch than inside. I have recently treated some of the plants with systemic insecticide and will be treating the rest of these houseplants now on the porch shortly.

Initially, I assumed that my mini orchids in the little terrariums would be safe against the spider mites because the environment inside would be very humid and wetter than spider mites might like. Thinking about it further though, clearly spider mites are present in high numbers in both my indoor and outdoor environment and I am afraid it is only a matter of time before my orchids develop spider mite infestations. I am not sure the high humidity alone will ward off the spider mites. Additionally, orchids this tiny (for example Lepanthes telipogoniflora) would seemingly succumb to these mites within days if not hours once the infestations begins.

So I guess I will have to keep a very close eye out for signs of infection, as it seems inevitable here. If and when I do notice it, what can I safely use to treat micro mini orchids that will not flat out kill the plants? Perhaps I could soak each plant in water for an hour or two each week to drown any mites starting to take over?

Generally, insecticides aren't effective against spider mites, which are arachnids not insects. Some combination preparations like Bayer's Advanced 3-in-1 do have a miticide in the formulation though it's a minor part of the mix. Permethrin-containing pesticides might help. Or you might need to go to a dedicated miticide. The label of any pesticide product should tell you which pests it kills... make sure that spider mites are on the list.

Also consider Azamax. It is a concentrated version of the active ingredient in neem oil, without the oil issues.

It is an insecticide, miticide, and to some degree, and insect repellent and growth regulator.

you could spray the plants with water with a bit of washing up liquid in it, you'd need to do for a while every few days to make sure all the mites are gone

Thank you all for your responses. I think I will make sure to keep all the previously infested plants on the porch and try to keep the door shut, since my orchids are in the adjacent room next to the window. Also, I treated all the porch plants with a really heavy dose of acephate so I don't have a bunch of infested plants on the porch near the orchids (even though the orchids are inside). I have decided that the spider mites may indeed leave the orchids alone, since they are in a very high humidity environment (perhaps very high humidity will prevent an infestation from starting, but in my experience will not itself stop an existing one) but will keep a close eye on them and use horticultural oil or soak in water if signs of pests appear.

Acephate is not a miticide.

You can add 5% (in volume) of alcohol to that solution. Apply once/week for a month.
Probably they won't be 100% erradicated but will be under control.

Good luck! I always worried that the pleuros might not take well to chemicals so it is good to know that it can be done, just in case. I had a bit of a mealy bug issue for the Dracula and was afraid to do more than wash the leaves with water.

While not technically a miticide, I did read online that acephate is at least someone effective against spider mites.

---------- Post added at 05:58 PM ---------- Previous post was at 05:52 PM ----------

I am still really leery about giving a tiny, delicate orchid like Lepanthes telipogoniflora, or leafless like Taeniophyllum obtusum, chemicals. Are you saying you have uses chemicals successfully on pleurothallids in the past?

No, I haven't tried any of these treatments. Except for a few mealie bugs, nothing has really bothered anything in my tank and I have just been washing off the leaves (with distilled or rain water). A vendor once told me that the pleuros were sensitive to chemicals (no idea if it is true). If I do ever need to go the chemical route, I think I will either first ask Andy of Andy's Orchids or Edgar of Windswept in time. Some of these orchids (i.e. Lep. astrophora) can be difficult to replace and I would rather not take a chance.

I had just assumed that the others posting had tried the treatments on pleuros before recommending it but, looking through the posts, no one seems to mention pleuros specifically.