I had bag worms on a small tree and pulled them off and sprayed with Sevin. I also have very large pine trees I want to protect. I found a few bags on them and removed. Is there a systemic I could use to protect them? If not, what can be done.
Unfortunately the bagworms may be too large now to effectively control with insecticides.
The best time to apply an insecticide is while the larvae are still small (less than 1/2-inch long), usually in early June. Small larvae are more vulnerable to insecticides, and feeding damage is relatively minor. Carefully inspect susceptible landscape plants. Young bagworms are hard to see at first; look closely for the small, upright bags which have the appearance of tiny ice cream cones made of bits of plant material.
Various chemicals and control options are recommended by UK. The following link discusses the chemical options available. Most systemic insecticides are commercial products that require a licensed, certified applicator to purchase and apply. Hand picking at this time of year is an organic control that is time consuming but effective. This is what UK has on bagworms and how to control them; timing is important depending upon the control options you choose.
Feel free to contact our office if you have other questions.
Let me know if I can help you further!
Jefferson County Cooperative Extension Service
810 Barret Ave
Louisville KY 40204