How soon in the early Spring can I spray dormant oil on scale?

Question

It’s cool still mid 40’s at night and mid 50’s as highs during daytime in north/western Frederick County, Maryland. When is the optimum time to spray dormant oil on major infestation of scale on boxwoods and Leuken Laurels?

Answer 1

Eggs are laid in late April and a new batch of this pest hatches in about 3 weeks. This is the time when treatment is most effective. Mature scale bugs wear shields, but the nymphs haven’t had time to develop them.

I would recommend neem oil spray. It is organic, but we have found it to be highly effective against scale and other sucking bugs. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm