Bagworms on Arborvitae Treatment: Stop Defoliation Fast
To stop bagworms from destroying your arborvitae, you need to spray the foliage with a biological insecticide like Bacillus thuringiensis (Bt) in late May when the larvae are actively feeding and vulnerable. If you wait until late July when the bags harden and reach 2 inches long, synthetic chemicals fail completely, leaving manual removal as … Read more