Spider mites on dendrobium?
 

Spider mite damage? I don’t see any webs. On dendrobium noble and microchip. My tolumnia are also yellowing. Help!

In my oppinion those are mites.
Not all mites species produce webbing.
But the treatment to erradicate them all is the same.

2% mineral oil in water? Other? I’m not against insecticides.

Once you get mites it's almost impossible to get rid of them for good.
A solution of 5 to 10% in volume of dish washer detergent plus 5% max alcohol sprayed all over the plants, especially on the underside.
Repeat every 5 days for a month.

If you can buy an acaricide then do it (here one need a special permit to buy them).

Mites are hard to get rid of? I had some (2 spotted mites) on a Den last year, I wiped down all the leaves with rubbing alcohol twice at one week intervals, and I haven't seen a mite since.

Bizarrely enough, I had a Den with very similar damage as the first Den pictured when I put it in too bright a spot. A few leaves burned, and many other leaves developed mite-like damage, and probably would have burned if I hadn't moved them plant.

Climate/environment is a key factor in their appearance and erradication. Under my conditions they are a certainty every summer. I believe they are there in winter too but with a residual population, which is enough for their outbreaks in summer.

They are native or naturalized in many places outdoors.

If you wish to completely get rid of them you should use an Acaricide. I recommend one that contains 'Abamectin'. There are few (Avid ..).Use according to instractions .You can mix with 5% oil .

I had similar damage on the same type of dendrobiums. I wiped down the leaves on the underside and never saw any spots or streaks. I assumed it was mites and so I continued to spray a with dish soap and alcohol solution, until I actually damaged the leaves by the treatment. I started to use Bayer three-in-one, alternated with azamax. But now I doubt that I ever had mites. I think it was a combination of too much light and not enough water. Those are just my two cents. My problem seems to have stopped but I increased my watering dramatically and have sprayed every week with something.

I agree with using Abamectin....Also there are a few others. Please check out my blog on how I treated mites in in the root zone.

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