TOM KAN PA wrote:

How do you prevent scale on house plants?

By buying plastic or silk plants :-)) Seriously, you can't really
"prevent" insect infestations, but there are a few things you can do to
reduce their occurrence and of course treat for them once they appear.
First, new houseplants should be quarantined for a period of time before
including in your houseplants groupings - most insects will hitch-hike
in on new plant material. Second, stressed plants will appeal more to
insects than those in good vigorous health, so tend to your plants
carefully by watering correctly, fertilizing moderately and providing
adequate light and humidity. Finally, should the insects appear, you
need to treat immediately. Most scale will have a hard exoskeleton which
makes using products like insecticidal soap and neem oil a waste of
time. If you are of a chemical bent, there are systemics available or
you can swab the plant gently with cotton balls dipped in rubbing
alcohol, focusing on the areas where the scale congregate. Scale is
tough to control and if you have a serious infestation, it is sometimes
better to cut your losses and get rid of the problem plant.

pam - gardengal