My Boston Fern has been outdoors all Spring and Summer and is magnificent.
I will bring it indoors now but what can I use to prevent scale from decimating the plant while still inside come early Spring? The scale waits until March to appear. I have used a wash of Ivory dish detergent and that just helps me keep the fern barely alive until I can take it outside once again. And the plant is so big that it is a back breaker getting it into the bath tub to wash!
There are two things you could try.
One is Bonide All Seasons Oil in their ready to spray bottle . This is listed for use on ferns. It works by suffocating the scale insects on the fronds. You might need to test the spray on a few fronds to make sure it will not injure the plant since ferns can be very sensitive.
The other product, which might be easier to use because it is a systemic and you don't need to spray, is Bayer Advanced 2-In-1 Insect Control Plus Fertilizer Plant Spikes. These are spikes that you just push into the soil according to the label directions and they will continue to feed and control many different insects for up to 2 months.You should be able to find either of these two products at your full service garden center.