Bagworms are tiny pests that typically infest evergreens, but can also be found on deciduous plants. They are most obvious in their bag stage on leafless winter trees, but damage from these insects isn’t always apparent until the infestation is heavy. Timing is important in controlling bagworms, so knowledge of their life cycle is necessary.
For heavily infested plants, bagworms are easiest to control when they are out of their sacks and actively feeding. A yearly tree & shrub drench (like those made by Bonide or Bayer) can be easy and effective to protect your tree against a range of insects. This is usually applied in March just before the tree begins to bud, or just after flowering for trees that are pollinated by insects. Otherwise spray regularly ever three to four weeks starting around mid-June with a product labelled for bagworms. We like Fertilome Natural Guard Spinosad or Bacillus thuringiensis (BT) because they are easy on the environment and safe for pollinator populations.
If your tree shows signs of insect damage, or you notice the sacks of bagworms in your landscape, stop in with photos or samples and we will be happy to advise you on the best course of action to take!