How soon in the early Spring can I spray dormant oil on scale?
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?
Certified GKH Gardening Expert
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