What could this be?

[calvin_orchidL]

I had/have exactly the same thing you have in the first picture on my dends. I think I agree with camille; they may be thrips based upon the observation that
1) I saw longish black insects that were visible to the naked eye walking around, although still quite small (around 1-2mm)
2) no webs/rust colored spots on a piece of paper when I tapped the leaf above (apparently this is how you tell if you have mites)

I sprayed with safers which controlled them, but they come back every winter. If you spray weekly for 3 weeks, they will go away, but the silver webbing will remain.

[ILS]

Thank you for your advise. When I sprayed the orchids today I noticed little tiny critters run for it. I also noticed real thin spider webbing. I went ahead and sprayed my other orchids and noticed the webs on some of them as well. Even though the leaves looked healthy.

I'm going to start treating them all routinely.

For the yellow one I'm wondering if it does not like the fertilizer or it is too strong for it. I just started fertilizing it a little over a month ago and it became yellow maybe two weeks ago - I'm hoping just changing the medium it is in and regular waterings will help. Maybe move it indoors too for the time being.

Thank you. Thank you! I really hope it works.

[lepanthes89]

To me it seems like the mites are just taking advantage of a weakened plant.I cant say for sure,since I dont know the conditions its grown under,but it seems thats a lot of fertilizer ,and possibly too hard water.
The leaves look too yellow,which could be too much sun.
In any case,I would adjust the growing conditions first,raise the humidity,spray with either dish-soap and water several times to get the hatching mite eggs,or horticultural oil and water,and if things dont improve with the next growth,toss the plant and medium and start again.
I have found that the huge amounts of time and energy needed to bring back a very sick plant are better spent on growing a healthy one instead.
good luck.

[orchids3]

After he cures the problem he needs to prevent a reoccurance. Improved airflow and humidity should go a long way toward preventing a new infestation if either is lacking no amount of pesticide will cure the problem.

[calvin_orchidL]

Just a question regarding spider mites - I read somewhere (maybe it was here) that you can enclose the plant in a plastic bag for a few days, during which the humidity will destroy all the mites. Repeat every week and soon the mites will be gone. I know this may be tricky for large dends but I have a small latouria type that has a mite infestation and I am trying this method now - anyone with experience?

I agree with orchids3 - apparently mites love dusty conditions, so airflow and humidity will definitely help (maybe you can set up a small fan?)

[Tindomul]

Wouldn't this rot the orchid though?

[calvin_orchidL]

Originally Posted by Tindomul

Wouldn't this rot the orchid though?

Hopefully 2 days per week won't do enough harm... I'm assuming that since sphag and bag works for me, this should be okay as well...we'll see!

[Brooke]

Calvin - spider mites also appear when the greenhouse is cool and VERY humid. As far as I am concerned, it is an old wives tale regarding hot and dry because in the outside world, it is always hot and dry when the mites show up in the garden.

If you can find a way to protect the media from getting drenched, a trip to the sink and the sprayer used on the foliage will keep them at bay until you can treat outside.

Trust me, humidity will not rid your plant of spider mites.

Brooke

[calvin_orchidL]

Originally Posted by brooke

Calvin - spider mites also appear when the greenhouse is cool and VERY humid. As far as I am concerned, it is an old wives tale regarding hot and dry because in the outside world, it is always hot and dry when the mites show up in the garden.

If you can find a way to protect the media from getting drenched, a trip to the sink and the sprayer used on the foliage will keep them at bay until you can treat outside.

Trust me, humidity will not rid your plant of spider mites.

Brooke

Hey brooke!

Perhaps what I had may not have been spider mites after all. I did the bag treatment and I also moved the plant to the office where there is a large window (It's a north facing window though) and for some reason all the little red specks disappeared and the stunted growth it was trying to put out suddenly grew an inch. Maybe the increase in light or humidity made the plant stronger and it warded off whatever was infesting it in the first place

[Brooke]

Or the eggs will hatch out and they will visit you again - LOL. I hope not but do watch for another visit from them in a week to 10 days.

Water spray can be your best friend during the winter.

Brooke