Arborvitae are not magnets to bagworms, but if you already have bagworms in your trees and shrubs, they will also attack arborvitae. Bagworms are caterpillars that make distinctive spindle-shaped bags on a variety of trees and shrubs throughout the USA. They attack both deciduous trees and evergreens, but are especially damaging to juniper, arborvitae, spruce, pine and cedar. Large populations of bagworms can strip plants of their foliage and eventually cause them to die. Infestations often go unnoticed because people mistake the protective bags for pine cones or other plant structures. Young larvae can be controlled with the botanical Bt (Bacillus thuringiensis) which is effective only against caterpillar type pests and has very low toxicity to people, or other insects. Hope this information helps you decide whether or not to keep your arborvitaes. |