How to Kill Bugs on a White Strelitzia Nicolai

Inspect the Strelitzia nicolai’s foliage for scale insects. Check the foliage for oval insects ranging in size from 1/8 to 1/2 inches in length. Look for insects clumped together in groups and attached to the plant’s stems or foliage. Scale insects are various colors, depending on the species, which include white, black, grayish or brown.

Check to see if the insects are alive or dead on the Strelitzia nicolai. Run your fingers across a scale patch. Touching dead scales results in the insect's hollow bodies flaking off the plant. Rubbing off live scales, leaves a moist, colored residue on your fingers. Kill small infestations by rubbing them off the plant with your fingers.

Apply a scale-killing insecticide on the plant. Use an insecticide safe for use on Strelitzia nicolai. Mix and apply the insecticide following product directions. Spray the insecticide over the infected portion of the plant, saturating the insects. Reapply the insecticide as needed and according to the product’s instructions.

Kill and control scale insects by smothering them with an application of horticultural oil in early springtime, according to Iowa State University. Follow the label’s instructions concerning mixing and amounts. Spray the entire Strelitzia nicolai plant with the oil. Repeat as needed, following package directions.

Treat the scale infestation by using an insecticidal soap spray. Mix the soap following package instructions. Spray the Strelitzia nicolai plant with the insecticidal soap mixture, saturating infected portions. Reapply the product if needed, following instructions.