Question
We've had this plant for over a decade. It's about 6' and has
white spider web like spots on it.How to rid the plant of this?

Answer
Hi Jim,

I am curious which "arboricola" plant species you are talking about?  Is this commonly called the "umbrella plant?"  This could be a _Schlefflera arboricola_ plant, commonly called the Hawaiian Umbrella plant.  

There are several insects, including spider mites, which may have infested your plant.  There are insecticides that can be used to treat for such infestations.  The Schefflera does have one particular enemy that can be pretty common: Spider Mites. To prevent Spider Mites from taking over, once a week or more give the plant a nice misting of a soapy water mixture. If Spider Mites become present, try this soapy water misting twice a day. If this does not work, visit your local garden center for a safe alternative.  Since your plant is a large specimen, it is not reasonable to think that a topical application of insecitcidal soap is a realistic treatment.  This, however, may be the only reasonable treatment until you can get the plant outdoors.  As you live in Pennsylvania, I would suggest that you treat in the spring time with a systemic insecticide, but this MUST be done with the plant outdoors.  


Check with your local garden center for a systemic insectide that treat for spider mites.