I know you don't want to hear this, but Malathion is the way to go. I had a terrible scale problem this year also. It has never been so bad. My cattleyas were infected down to the rhizome. I spent four weekends dipping and scrubbing them. I filled a 32 gallon trash can with malathion and soaked my orchids for 5-10 minutes then took a tooth brush and scrubbed them down to the roots to remove scale. Next, I took a systemic spray and sprayed them. I have been spraying with malathion once a week since. Most of my scale problems are gone, but it still pops up here and there. I lost several beautiful cattleyas to it. Death to Scale!!