What Is Light Horticultural Oil And How To Apply It

Question From: L. Gonzalez - Midlothian, Virginia, United States
Q: I'm looking for a "light horticultural oil" for treatment of spruce mites. Light oil was recommended so as not to needlessly kill beneficial insects that help control the mites. Can you recommend either a brand, type or generally how to tell if what I use is "light"?....thanks.

A: Check out this link from MSU regarding use of light oils on trees: http://msue.anr.msu.edu/news/using_horticultural_oils_on_landscape_plants. If this is a large tree your best bet is to get an on site inspection and treatment from a professional. You may have more than one issue. Some oils will discolor fir trees, be srure to read the labels carefully. Best And Happy Yardening, Nancy