Dr. Gillian W. Watson, California Pest Prevention Service’s Entomology Lab, emailed the results regarding the plant sample that I mailed last week for scale identification. Dr. Watson recognized the scale on my “Stairway to Heaven Jacob’s Ladder” (Polemonium reptans) plants as Coccus hesperidum, Common name Soft Brown Scale, C rated (native insect).
Dr. Watson also wrote, “Unfortunately, as an identification lab we cannot advise you on how to control them. Your County Agricultural Commissioner’s office can help you in that way or perhaps your local Nursery.”
Instead of contacting the suggested services, I turned to my Pests of Landscape Trees and Shrubs book for a quick read. Fortunately, Soft Brown Scale seldom causes serious damage. One recommendation is to treat with horticultural oil during dormant season or in spring when crawlers are active. The text also suggested removing heavily infested branches. Unfortunately, most of the stems and leaves on my plants were extremely infested. As I shared before (see September 22 post.), I opted to pull them out.
Although I lost two of my favorite plants, I view this backyard experience as a learning tutorial: Examine my plants closely at the first sign of trouble, and send a sample for insect identification ASAP.