You need to know that mealy (aka bugs woolly) aphids attack many types of plants, not just the orchids. The fact is that this insect is a parasite that feeds on the plant sap.
If you have a plant infested with mealy bugs, you must act rapidly because it can attack the other plants in your home or garden. You can recognize it easily because it is a white, fluffy, small-sized insect which lays many eggs and whose larva forms at the base of the leaves and stem of the attacked plants a kind of substance like a fine cotton wool. Then, sticky substance remains on the leaves, the result of insect metabolism.
Those sticky traces, just like the thin cotton wool on the plant, indicate that the orchid was attacked by the mealy bug parasite.
How to remove these mealy bugs for good
1. Remove all adult insects you can see on the surface of the leaves with a cotton swab soaked in rubbing alcohol.
2. To remove mealy bugs larvae and eggs, you must apply an insecticide. You can use Actara insecticide and an adjuvant, whose role is to improve the insecticide’s action. The solution obtained by mixing the insecticide with the adjuvant is applied to the whole plant by spraying. This treatment is repeated after 7 days.
If after two applications the problem persists, you need to use another type of insecticide, stronger, such as Karate Zeon or Reldan. I hope this info will help you!