Scientific name: Order Lepidoptera, family Psychidae, Thyridopteryx ephemeraeformis
Size: Adult--up to 1", bag--1/4" to 1 1/2", larva--3/4" to 1"
Identification: Larvae hang in bags from twigs of trees. Bags are camouflaged with pieces of twigs and leaves from the host plant. Adult male is a black moth. The bag has a small opening at the narrow lower end that serves as a waste exhaust port. A wider opening at the top allows the larvae to crawl out and feed.
Biology and life cycle: Newly hatched bagworm larvae make conical bags that they carry upright as they move. Adult females are grublike, have no wings or eyes, and are nearly hairless. The rarely seen male adult is a small flying moth. It has clear wings and feathery antennae and is sooty black. The female lays eggs in the bags in the fall, then goes through the lower opening and drops to the ground and dies. Larvae hatch and lower themselves on silk threads and attach on limbs where they start building their own silk bags.
Habitat: Ornamental trees and shrubs like arborvitae, junipers, fruit trees, and many others. Stressed plants are particularly vulnerable to this pest.
Feeding habits: Eat foliage starting on the upper part of the plant. They live in and feed on willow, cedar, cypress, some pines, boxelder, locust, sycamore, maple, sumac, persimmon, and other ornamentals and fruit trees.
Economic importance: Defoliation of ornamental plants.
Natural control: Wasps, birds, and several insect parasites and predators.Releasing trichogramma wasps in the early spring at leaf emergence is an effective preventative.
Organic control: Bt (Bacillus thuringiensis) products sprayed in the spring. Hand picking the rest of the year is by far the best technique. Plant oil products will kill the moving and feeding females in the spring.
Material for making the bags.
Insight: Texas has several recorded species of bagworms. Since the female doesn't have wings or ever leave the bag, it is somewhat of a mystery how bagworms get dispersed. While the larvae are attached to single strands of silk thread after hatching, they may be blown a distance by the wind. The silk thread could get caught on an animal such as a bird and be carried a distance.
Defoliating insects that attack several tree species. Hand remove bags then apply The Sick Tree Treatment. Once the bags has firmly attached to the plant, the only solution is to pull them off and toss into the compost pile. When the female worms are pulling the bag around and feeding in the spring, spray with Bt products with 1 ounce of molasses per gallon of spray and release trichogramma wasps.