We apologize, but there is no way we can say for sure if the tree will survive. We recommend that you contact a local arborist with your cooperative extension office to determine the extent of the damage of the tree. Talstar is labeled for a foliar spray starting in April through June.
It is important to start control methods before a major infestation occurs. Once the bagworms have matured and have formed the "bag" most chemical control methods will no longer work.
You can manually control bagworms by simply plucking them off of the infested trees and dropping them into a bucket of soapy water or squishing them. This control method is most useful during fall, winter and early spring, before the eggs inside the bag have hatched.
Chemical control may be achieved when the larvae are small and just emerging from the over-wintering bag. Use a concentrated liquid insecticide such as Talstar or Tempo. Foliage should be thoroughly wetted with the insecticide spray in order to achieve thorough coverage. When doing an insecticide treatment, timing is key. To find out the correct time of year to treat for bagworms in your region contact you local Cooperative Extension office. These offices can prove to be invaluable when treating for insect pests.