Spider mites

[NYCorchidman]

How many orchids do you have?
If you have just a few, then manually washing the leaves down helps.

I know it sounds like a tedious work, but that's how I deal with them if I ever have them on my plant, which rarely happens but one of my tall nobile dendrobiums got some spider mites in the fall two years ago.

One thing is, spider mites (and other mites) in general indicate you are not watering your plants enough (underwatered thus stressed plants seem to have special magnetic attractions for mites) or the air is too dry.

I'm an indoor grower, so except for the summer when I leave my window open and the humidity naturally stays relatively high here in NYC, the air tends to be rather dry.

I mist my plants often and try to water all my orchids well as long as I remember or have time for them.

Then I also check the back of the leaves quite often just in case there are any mites hiding. Spider mites are easy (at least for me) to identify visually because they are much bigger than some other mites.

If intestions are bad, and even if it isn't too bad, first either wash down or wipe off them all off with water.

If possible, mist the leaves every morning.
Wash down the plant (especially the back of the leaves) with either plain water or mild soapy water every other day for a couple of weeks and that is usually the end of spider mites. The reason you need to wash them off this often is so that you get the missed ones from previous washing and the new hatchlings.
After about a couple of weeks, you manage to break the cycle and they are gone unless they are reintroduced, which they can, if you leave your window open, they can travel in easily.

Also, if you have other houseplants around, check them for the presence of mites.
I find orchids to be much more resistant in attracting bugs compared to other plants.
so check other plants if you have them near your orchids.
I had to discard one houseplants that was loaded with mites while orchids near it had none on them.
Orchids are tough, but they need care.

[RHF]

Low humidity is typically associated with spider mites, as stated above. If your collection is less than a couple hundred plants, I would treat them individually and then follow typically 'best practice', which would be to treat all plants in the general area - one to two plants in all directions should be enough for spider mites.

I typically use a 409/propanol alcohol mixture for insects. Mix 1 part original 409, 1 part rubbing alcohol and 2 parts water and place in spray bottle. Spray all surfaces of the plant - for tough insects - like white scale - brushing with a toothbrush helps. Also, removal of any old leaves or sheaths (anything bugs can hide in or under) and don't forget the cracks and crevices.

RHF

[Andre]

Thanks for the ideas. I live fairly close to the US border, so I might have to make a trip. I'll try to find the bayer spray. My collection is about 100 plants, so a systemic product would be my choice.


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[RosieC]

Originally Posted by NYCorchidman

How many orchids do you have?
If you have just a few, then manually washing the leaves down helps.

I know it sounds like a tedious work, but that's how I deal with them if I ever have them on my plant, which rarely happens but one of my tall nobile dendrobiums got some spider mites in the fall two years ago.

Agreed, this is what I've done on some keikis that have had spider mites.

I found that repeated washing down of the leaves (every couple of days while watering) seemed to get rid of the mites. However I did have a re-occurance of them months later... was it because I had never got rid of them or just because they are attracted to this particular orchid... I don't know. However washing them down regularly again the last couple of months and I've seen no more sign and the keiks are growing well.

However these are small plants, and while there are a lot of them it's fairly easy while watering to just pour all over and rub each leaf down with my fingers.

With the much bigger parent plant I gave up because it was much harder to manually wash down on a regular basis.