Bagworm bags

Bagworm season is upon us! Illinois was hit hard last year and this year may be no different. If you had bagworms last year, start inspecting your plants now for infestation. Because the bags serve as an overwintering protection for the eggs that hatch the following year, the pest may continue year after year. The bags seen in early spring are leftover from the previous year. Each bag can contain over 500 eggs. Small worms will hatch from the eggs in these bags and start feeding immediately. This is the most vulnerable stage in the bagworms life and the best time for treatment. At this stage, the worms are grayish black and very small. Because of their size, careful inspection is required to find them. One clue is the feeding damage that has already occurred.

Infected deciduous trees (trees that lose their leaves in the winter) attacked by bagworms are more likely to releaf the following year. Evergreens are not so lucky. Evergreen tree and shrub branches stripped by bagworms usually die. If enough branches die, the entire tree or shrub is in jeopardy. Favorite hosts of the bagworm include, but are not limited to, arborvitae, spruce, junipers, honey locust and linden trees.

The lifespan of the bagworm has a few stages and appearances. After the small worms hatch from their eggs they continue to feed on their host and grow to a caterpillar and then a pupa stage. The adult females emerge from the pupa stage without legs or wings. They remain on the host plant to lay eggs that will hatch the next year. And so the cycle continues. The bags can be pulled off of the host plant, in addition to treating the younger pest stages. Contact the Plant Health Care Department at KTS to discuss options. Our Certified Arborists can properly identify and offer treatment suggestions to save your trees and shrubs.

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