National Moth Week 2023 - Common Bagworm Moth

Moths do not find universal appeal. The common bagworm moth, scientifically known as Thyridopteryx ephemeraeformis, belongs to the family Psychidae. There are around 1,300 species of bagworms. Bagworms are the larval stage of certain moth species that damage evergreen and deciduous trees. The name bagworm comes from the fact that the worm-like larvae emerge from bag-like casings.

The life cycle of Thyridopteryx ephemeraeformis in cooler climates starts when the eggs hatch in the end of May and beginning of June. This species emerges earlier in Florida and can be bivolutine (two generations in a year) in southern regions during warmer years.

Once the eggs hatch, the larva spins a silk strand that hangs down it. The larva can also be transported to nearby plants by wind. Once the larva finds a host, it starts to make a new protective bag around itself. It remains inside this bag sticking only its head out to eat from the host. The larva continues feeding until it matures by the end of August. It then attaches the bag they are in to a branch with a strand of silk and starts developing into a pupa.

The bagworm moth generally resides and feeds on willow, maple, bald cypress, native roses, black locusts, pines and over 120 other deciduous and evergreen species. Larvae are known to subsist on fruit trees, ornamental trees, perennial flowers and decorative shrubs making the bagworm moth’s diet diverse and adaptable.


Adult males emerge in early fall with a wingspan of 25 millimeters. These are small, dark moths with fur on their body and transparent wings. Adult bagworm females are wingless. They never leave the protective bag. She remains in her bag for the male to find and mate with her. The female will then produce 500-1000 eggs within her bag and then dies.

In residential landscapes, bagworm moths can be hand-pulled from surfaces in cooler months as some contain the wingless female or her clutch of eggs that will hatch in spring. The author recommends BT (Bacillus thuringiensis) spray as a biological control at dusk in spring- when the bag’s size is small and the moth more susceptible. Providing habitat for natural predators such as spiders, syrphid flies, and parasitoid wasps are, as usual, best practices. The bagworm is very common in urban settings and should not cause alarm to the better-informed reader.

Come celebrate moth awareness week collaboratively with National Moth Week and Florida Native Plant Society. Like and share your own experiences with us.

Caterpillar image courtesy of Judy Gallagher
Adult image courtesy of Andy Reago and Chrissy McClarren


Caption provided by FNPS President, Mark Kateli
Instagram: @markkateli | Facebook: Mark Kateli