They love most any arborvitae but will also eat maple, boxelder, willow, black locust, poplar, oak, apple, cherry, persimmon and just about anything with green leafy leaves. Bagworms are insects that require control as they can defoliate evergreens and sometimes deciduous trees/shrubs. BAGWORMS DAMAGE TREES, SHRUBS AND FLOWERS ^ Bagworms eat plant and tree leaves and can cause substantial damage if left alone. But if they eat more than 80 percent of the tree, the entire evergreen may die. If you can reach the bagworms, handpick as many as you can now and drop into a bucket of soapy water and remove any from the ground as they can complete their life cycle. Whatever the cause, bagworms leave a trail of destruction in their wake. Although bagworms can feed on a variety of different plants, 128 by one count, they generally prefer arborvitae and bald cypress in my part of Texas. They are covered with dead needles, so they appear more noticeable in contrast to the green deciduous needles at this time. Once these trees lose their leaves, they die. Bagworms, found throughout the Eastern United States, are a major pest for evergreens. Bagworms (Thyridopteryx ephemeraeformis) are caterpillars, and pine trees (Pinus spp.) Most trees will see partial defoliation; however, some heavily infested trees will experience complete defoliation. Continue to water through October. Treatment for bagworms can only start at certain times during their lifecycle. According to Matt Grubisich, urban forester with Urban Renewal consulting in Arlington, TX Bagworms feed on a variety of deciduous and evergreen plants including arborvitae, juniper, spruce, pine, maples, sycamores and numerous others. Bagworm eggs overwinter in the bags, so removing the bags in winter is an effective method of control. This pest feeds on host plants, causing extensive damage to the tree.


Evergreen trees and shrubs cannot recover from complete defoliation; whereas deciduous trees usually develop new leaves following defoliation. Bagworm sacks can be very hard to find because they look like pine cones. These wasps will parasitize the bagworms and take care of your problem. Bagworm egg sacks are brown and one and a half to two inches (3.8 to 5 cm) long. The bagworms overwinter in the bag that was put there by last year’s females. It's very common for this kind of browning to seem to happen overnight because the bags blend in so well with the plant foliage. Pine Trees and Bagworms. They may look like pine cones or other plant structures. Can a Brown Evergreen Come Back?. These insects are known for the cone-shaped bag they create around themselves, hence their name. Once an evergreen or a branch turns completely brown, it will not recover. Their leaves can get gnawed on causing them to shed leaves. Wasps and hornets are also natural predators of the bagworm so there are gardeners who have had success introducing ichneumonid wasps to their infected areas. Commonly mistaken for swaying in the wind, these bagworms move in their cocoons which causes them to sway back and forth throughout the day. You'll likely have to wait until next spring before knowing if the tree completely recovers.
On the other hand, deciduous trees like the oak are more resilient against bagworms that evergreens. The cases can be surprisingly strong and you can do serious damage to your tree by pulling too hard. The bag structure itself will prevent any insecticide from entering, therefore rendering it harmless.

Trees can recover from a stripping for a season, although multiple repeated onslaughts or bag worms combined with other issues over time may kill them. If your arborvitae is infested with bagworms, it is important to get rid of the pest before extensive or repeated defoliation occurs. They make a cocoon-like bag in which to live, while they hang on the branches of trees and shrubs to feed. Many evergreen owners are concerned about bagworms. This is likely to be the case for many bagworm-infested evergreen trees where bagworms were not controlled early or well enough to halt damage. But if they eat more than 80 percent of the tree, the entire evergreen may die. The tiny caterpillars are hard to see and their 1 1/2- to 2-inch bags are camouflaged because they are made from parts of the plant. But, they can recover when the bagworms disappear. Although late summer is the time they are most noticeable they a best treated for in late spring after they hatch.