One of my arborvitae seemed to die overnight. I noticed many of these "bags" which looked like small pine cones. After doing online research, I realized my arborvitae was infested with bagworms. This was in August. We have removed 90% of the bagworms (still finding them occasionally, as well as in the neighboring arborvitaes). I understand in May is best time to spray them. Is there a particular spray you could recommend that wouldn't be harmful to humans and our dog? Would you recommend we hire an arborist to spray or can we do this effectively ourselves? I wonder if our arborvitae will come back or if it's dead - it does have some greenery still. Thank you very much.
Certified GKH Gardening Expert
Bt (Bacillus thuringiensis) products sprayed in the spring can be successful in the control of bagworms. In addition, hand pulling or power washing the 'bags' off the plant may be an adequate form of control. Here is an article or two that you may find helpful: https://www.gardeningknowhow.com/plant-problems/pests/treatment-bagworms.htm