Controlling scale on Pachysandra
For the last 5 years, I've experienced severe damage to several pachysandra patches as a result of scale infestation; they always seem to sneak up without warning. I'd like to use a horticultural oil this season to control them. Is this a good time? Is it safe to use on pachysandra?
Kent County Maryland
Your pachysandra has euonymus scale. A dormant horticultural oil is what we would recommend:http://extension.umd.edu/hgic/armored-scales-groundcovers Be sure to read the label closely for the temperature parameters.
Some euonymus scale can exist on pachysandra with minimal harm, provided the pachysandra is healthy and natural predators can keep down the scale population.