Best Way to Treat Bad Case of Scale on Dendrobium?

[Bill_NeOh]

I agree with Ross, once you have scale the best you can hope for is control. At one point I thought I was scale free. No signs of the buggers for at least 6 months. I quit treating and the next time I had humidity problems and no airflow in one corner of the greenhouse, yep, there they are again. I know which orchids to watch for them to appear. I usually do not have problems keeping the scale out of my dens.

I spot treat with Bayer “Dual Action Rose & Flower Insect Killer Ready-To-Use”
Bayer Advanced ™ Dual Action Rose & Flower Insect Killer Ready-To-Use

and I add about 1 1/2 teaspoon of Bayer “Tree & Shrub Insect Control Concentrate”
Bayer Advanced ™ Tree & Shrub Insect Control Concentrate
to 2 gallons of water when I fertilize.

This seems to keep them hiding.