Scale insects are very common pests of Schefflera and very hard to get rid of. It takes a lot longer than a few weeks for an infestation to get bad enough to cause obvious decline in a plant, so this has been an on going but difficult to detect problem.

Is this plant inside?

Wipe them with a cotton swab soaked in rubbing alcohol....a tedious task but it will kill them.....

Tedius and not very effective....these insects will be found on the leaves and stems and in every nook and cranny. IF alcohol kills scale, then a solution of one part alcohol (isopropyl) to three parts water can be applied with a spray bottle. Scale are not something I would use alcohol for, however. I've not found it very effective.

I'd rather see danella purchase a small container of a horticultural oil, mix it up according to label directions, and apply to all surfaces with a plant sprayer. Oils should not be applied in high temperatures, which is why I asked if this plant is out or in.

The oil needs to cover every surface of the plant, so don a pair of disposable gloves in order to mist with one hand and carefully turn the leaves over so that the backs can be sprayed.

My favorite scenario would be that the plant gets a mild soap and water sponge bath first, then the hort. oil treatment. Follow the label directions pertaining to the follow up applications.

Be sure to inspect other plants.