Hello, I have a Majesty palm that has a scale infestation. I rinsed it with water, let it dry, then sprayed with Safer's insecticidal soap. I repeated the spray again about 3 weeks later. There has been no improvement. I bought the insecticide a number of years ago. Can't say when. Could it be that it has lost its potency? Should I buy more or try something else? Or just get rid of the plant and replace it. Thank you for your expert advice and service. Patti
No, it's not that the insecticidal soap has lost effectiveness it's the fact that scale insects are very difficult to control on houseplants. It can take much time and effort to get it under control. That is why many folks just decide to replace the plant instead of fighting it.
If you want to keep trying look for a systemic houseplant insecticide that gets sprinkled in the soil. There is one Bonide product labeled for houseplants. Although even this would not be too effective if the scale population is established on the plant.
The following is the information on scale from our website, http://extension.umd.edu/hgic/scale-insects-houseplants
Another option is to isolate the plant and nurse it along just long enough until it is time to move it outdoors for the summer. Keep spraying the plant with the insecticidal soap to try to keep the scale at bay. When outdoors natural enemies and beneficials with keep the scale under control. When it is time to move it back inside, before doing so, thoroughly spray it with the insecticidal soap.