Scientific Name: Thyridopteryx ephemeraeformis (Haworth)



Bagworms are most easily recognized in the landscape by the cone-shapedcase or cocoon-like bag that the caterpillar forms and suspends from ornamental plants on which it feeds.These insects can be found feeding on the foliage of nearly 125 different trees and shrubs all throughout New Jersey.





Life Cycle

Spring---Upon hatching in late May to early June in Mid-AtlanticStates, the young larvae mmediately begin to feed. As they feed, each larva constructs a 1- to 2.5-inch bag orcase, resembling a small pine cone, composed of plant partswoven together with silk. It spends most of it larva stage in this ‘bag’ and only partly emerges when feeding. The young larvae have black tops and dull amber undersides. Fully grown bagworm larvae are gray with darker heads.

Summer---Growth and molting continue until late July to mid-August,when the larvae stop feeding. In order to pupate, each mature larva enters and closes the bag with a band of silk. The pupalstage lasts for about four weeks.






Bagworms are ubiquitous in the landscape and can damage a wide range of both evergreen and deciduous shrubs and trees.

Common evergreen hosts are arborvitae, juniper, cedar, fir, pine and spruce.

Deciduous hosts include birch, boxelder,elm and willow, sycamore, black locust, honey locust,persimmon, poplar, maple and sweet gum.

Bagworms can be spread accidentally by transporting andplanting infected nursery stock. Travel from plant to plant is generally slow as the females cannot fly, but the larvae can crawl to nearby plants if knocked off the original host plant. In addition, the larvae can move on the wind by “ballooning” or sailing to adjacent or downwind host plants. They do this by producing long silk threads that catch the wind and carry them to new food sources.



The young bagworm larvae feed on the upper layer of the leaves,leaving brown spots. Eventually, leaves of heavily infested deciduous trees can be skeletonized leaving only the mainleaf veins. Evergreen trees will show loss of foliage and thinning of the canopy as larvae strip the needles and eat the terminal buds. First branches, and then an entire tree, maybe defoliated, which will kill an evergreen outrightand severely damage or kill a deciduous tree.





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