Cut off and destroy the infected branches by burning them. Treat the remaining branches with insecticide so as not to infect the other surrounding plants
Attract parasite wasps and lady bugs to the infected plants. These are predator insects that feed on scale insects. Once they have eaten all the insects, they will leave on their own.
Wash the plants with soap and water. Mix 2 tsp of liquid soap in a gallon of water. Put it in a spray bottle and coat the soapy liquid thoroughly on the stems and leaves. Covering both sides of the leaves. And then rinse the plant with room temperature water.
Spray the plant with horticultural oil. This is safe for other insects and plants. An example of this is neem oil.
You can also try scrubbing the scale insects off the plants from a light brush with the soapy water mixture.
Spray the plant with commercial insecticides and pesticides according to their respective product use instructions. For the protection of sensitive plants, fruits and vegetables and your pets, use the least toxic chemical insecticide and pesticide available in the market.