The plaster bagworm, scientifically known as Phereoeca uterella, is a pest commonly found in households. This small critter is often mistaken for an actual bagworm; however, they are only distantly related.
The plaster bagworm, or household casebearer, thrives in warm, humid environments and can infest various locations in your home, especially where dust and debris accumulate.
These pests create protective cases made of silk, which they camouflage with bits of their immediate surroundings, such as plaster, dust, and other debris.
As they mature and feed, they can cause damage to household items and surfaces such as walls and curtains. It is essential to be able to identify and control plaster bagworms to prevent potential infestations.
Identification of Plaster Bagworms
Morphology and Appearance
- Larvae are encased in a silk bag covered with debris
- Adult male moths have wings and a furry body
- Adult female moths are wingless and maggot-like
Larva vs Adult Moths
The larval stage of the plaster bagworm involves a caterpillar-like insect living inside a protective silk bag. Adult moths, on the other hand, differ in appearance:
- Larvae: Typically brown or tan, they create a spindle-shaped silk bag camouflaged with debris.
- Adult Male Moths: Appear bee-like, having clear wings and fur.
- Adult Female Moths: Wingless, maggot-like, and yellowish-white, they lack functional mouthparts and legs.
Some distinct characteristics of plaster bagworms include:
- False legs: Larvae have false legs, allowing them to move while inside their silk bag.
- Habitat: They prefer damp environments and can be found on walls, especially in bathrooms and laundry rooms.
- Food source: The larvae feed on wool clothing, spiderwebs, and other organic materials.
Remember to look for the unique silk bags and appearance of the larvae and adult moths to identify plaster bagworms.
In case of an infestation, consider using moth traps and keeping your home clean to minimize their presence.
Habitat and Distribution
Plaster bagworms are commonly found in states like Florida and Louisiana. They thrive in coastal areas due to the high levels of humidity and moisture.
In Florida, it is common for homeowners to spot plaster bagworms on their stucco walls near crevices or cracks, especially in coastal areas where humidity levels are consistently high.
However, their range is not limited to these states, but they are less common in drier climates.
These household pests prefer environments with high humidity and moisture.
They are often found on walls, ceilings, and surfaces made of stucco and plaster. They also seek out dark, hidden spaces such as crevices and cracks in the walls.
|Environment||Plaster Bagworm Level|
|High humidity||More likely to find plaster bagworms|
|Low humidity||Less likely to find plaster bagworms|
|Coastal areas||High probability of plaster bagworm presence|
|Stucco||Suitable surface for plaster bagworms|
|Plaster||Suitable surface for plaster bagworms|
Life Cycle and Reproduction
Eggs and Larval Stage
Phereoeca uterella, also known as the household casebearer, begins its life as an egg within the female’s case. Female casebearers lay their eggs inside their cases, where the larvae hatch.
These larvae then create their bagworm cases made of silk, and attach debris such as wool or sponge to the exterior.
A unique feature of the larval stage is their mobility, as they carry their cases wherever they go. Some examples of their cases include:
- Silk interwoven with plant material
- Small debris particles like dust and sand
- Tiny fibers from materials like wool or lint
Larvae feed on organic material like spiderwebs, which they consume while moving around in their cases.
As larvae grow, they eventually enter the pupal stage. During this phase:
- They seal the opening of their case
- Transform inside the case over the course of 1-2 weeks
After pupation, adult bagworm moths emerge from the cases. Notably, males and females differ:
|Focus on reproduction||Focus on laying eggs inside cases|
Once the adults complete the reproduction process, their life cycle concludes. The eggs are laid within the cases, ensuring the continuation of the species.
Feeding Habits and Diet
Plaster bagworms, also known as household casebearers, primarily feed on organic materials found around the home. Some examples of their preferred diet include:
These small creatures can often be found in areas with high levels of humidity, which helps soften their preferred food sources.
Dead Insects and Spider Webs
In addition to organic materials, plaster bagworms also feed on protein-rich sources such as dead insects and spiderwebs.
Dead insects provide essential nutrients, while spiderwebs are an easy-to-access food source for these critters.
|Food Source||Attraction for Bagworms|
|Dead insects||High protein content|
|Spiderwebs||Easy access and availability|
Cobwebs and Debris
Other than organic materials and dead insects, plaster bagworms also consume cobwebs and debris found in and around homes.
They have been known to feed on Sand, Dust, and Miscellaneous debris
This diverse diet allows plaster bagworms to thrive in a variety of environments and maintain a healthy life cycle.
Plaster Bagworm on Wall: Prevention and Control Measures
Cleaning and Maintenance
Regular housekeeping helps prevent plaster bagworm infestations. Focus on:
- Vacuuming corners and baseboards
- Dusting patio furniture
- Deep cleaning living areas, especially in places they may hide
For example, use a vacuum cleaner with a long hose attachment to reach high corners where bagworms could be hiding.
Dehumidification and Air Conditioning
Maintaining appropriate humidity levels is essential, as bagworms thrive in damp environments. Use:
- Dehumidifiers to decrease humidity
- Air conditioners to achieve a comfortable temperature and reduce humidity
- Regularly cleaning and maintaining air conditioning systems
With a balanced environment, bagworms are less likely to infest your home.
Pest Control Methods
Various pest control methods can be employed against plaster bagworms. Find a method that suits your needs and preferences:
|Pesticides||Quick and effective elimination of pests||May harm beneficial insects|
|Essential oils||Natural, non-toxic option||Efficacy can vary from species to species|
|Manual removal||Immediate, reliable results||Time-consuming, labor-intensive|
Examples of natural pest control options include using essential oils like lavender or peppermint oil, which can deter plaster bagworms.
For severe infestations, chemical pesticides can be effective, but use caution in choosing products due to potential harm to the environment or beneficial insects.
Manual removal involves hand-picking bagworms from trees, furniture, or corners, and either sealing them in a trash bag or destroying their cases. Remember to wear gloves and dispose of the pests properly.
Signs of Infestation and Common Damage
Recognizing an Infestation
Household casebearers, also known as plaster bagworms, are small pests that can infest your home. To recognize an infestation, look for:
- Small, oval-shaped cases hanging on walls, ceilings, or furniture
- Silken webs near the infestation site
- Adult moths flying around indoor or outdoor light sources
For example, plaster bagworms might be found in areas like garages or near outdoor security lights.
Impact on Homes and Property
Plaster bagworms can cause several issues in your home:
- Weakening of plaster walls by feeding on the foundation
- Unsightly webs appearing in corners or on furniture
To protect your property, consider preventing plaster bagworm infestation by:
- Using yellow bulbs for outdoor lights, as they attract fewer insects
- Regularly cleaning and inspecting vulnerable areas, such as walls and ceilings
|Issue||Plaster Bagworms||Other Household Pests|
|Attraction to Light||Yes||Varies|
To get rid of plaster bagworms, you can:
- Remove their cases by hand, ensuring they won’t reproduce
- Use insecticides within a few days of egg hatch for better efficiency
In summary, plaster bagworms are insects that belong to the family Tineidae. They have worm-like bodies and make cases from silk and organic materials.
They are found in humid regions of the world, where they feed on spider webs, wool, and other fibers. They hatch from eggs inside the female case and go through several instars before pupating in their own cases.
They emerge as moths in spring or summer. They are usually harmless insects, but they can cause aesthetic problems or damage walls if they occur in large numbers.
They can be controlled by vacuuming, cleaning, or using natural or chemical pesticides.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Bagworm
Subject: New Mexico Bagworms
Location: Albuquerque, NM
January 14, 2017 5:19 pm
These bagworm “cocoons” are now very common in the bosque (forest) along the Rio Grande in the area of Tingley Beach in Albuquerque, NM.
They are almost exclusively hanging from the salt cedar AKA Tamarisk on the flood plains adjacent to the river.
Can anyone identify a genus/species for these?
Signature: James Hunter
Our inability to provide you with a conclusive identification is no reflection on the excellent quality (and aesthetic merits) of your high resolution image. In the pupal state, many Bagworms look very similar.
We thought that providing a food plant might help with identification, but in attempting to provide you with an identification, the most valuable information we learned on Texas Invasives is that Salt Cedar is an invasive exotic plant, which leads us to believe the Bagworm might not be a native species.
Thanks for your reply.
My very limited research has led me the genus Thyridopteryx; possibly a variation of the species ephemeraeformis.
A quick reference (http://entnemdept.ufl.edu/creatures/MISC/MOTHS/bagworm.htm) notes that for host plants:
“Thyridopteryx ephemeraeformis can feed on over 50 families of deciduous and evergreen trees and shrubs. Common hosts include juniper (Juniperus spp.), arborvitae (Thuja spp.), live oak (Quercus virginiana), Southern red cedar (Juniperus silicicola), and willow (Salix spp.) (FDACS 1983).
Other hosts include maple (Acer spp.), elm (Ulmus spp.), pine (Pinus spp.), Indian hawthorn (Raphiolepis indica), ligustrum (Ligustrum japonica), and viburnum (Viburnum spp.).
One of the authors has received unconfirmed reports of common bagworm as an economic pest of Adonidia palms (Veitchia merrillii) in south Florida (S.P. Arthurs 2016).”
Willows are very common in the Rio Grande bosque, and/or these little guys may have adapted to feeding on Tamarisk.
The map on this page (http://www.butterfliesandmoths.org/species/Thyridopteryx-ephemeraeformis) and the detail (http://www.butterfliesandmoths.org/sighting_details/917285) reports ephemeraeformis feeding on a willow in Albuquerque.
The closest other records are in eastern TX, OK and KS. Perhaps an “invasion” is in progress.
James C. Hunter, RG
Hi again James,
Thanks for providing all your research for our readership. We just do not have the staffing to research every posting as thoroughly as you have done. That is quite a diverse group of food plants for a single species.
Letter 2 – Bagworm
Hi bug man
We have identified this as a bag worm ( Thanks to your great site!) It has been hanging on our outside light fixture for about 6 months-it is starting to emerge from the bottom–what can you tell us about this and what will it do? Thanks,
Interested in bugs in Florida
If this is a female, and it does look to be a female, she will remain legless and wingless. She will emerge just far enough to mate with the winged male when he is attracted to her pheromones.
She will then crawl back into her bag, lay eggs and die. Young caterpillars will hatch, disperse and form their own bags. If a male emerges, he will fly until he is attracted to a female.
Letter 3 – Bagworm
Location: Portland, TN
July 30, 2012 8:02 pm
Hi there, I saw the ”bug” today I’m stumped. At first I thought it was a broken piece of a pine tree branch, then it started moving. A caterpillar started to crawl out of one side and when I touched it, it went inside the ”shell”. Any ideas? Thanks.
Signature: Jason Waldron
You are correct that this is a caterpillar. It is a Bagworm, the caterpillar of a member of a family of moths with larvae that construct bags from silk and plant material.
The Bagworm drags its bag about, adding to it as the caterpillar grows. Eventually it will pupate within the bag. Adult males are winged and they can fly in search of a mate, but adult females are without wings and they remain inside the bag after metamorphosing into adults.
The male enters the bag of a female to mate and she lays eggs inside the bag. The final role of the bag is to shelter the eggs over the winter when new caterpillars will emerge and spin bags of their own.
Letter 4 – Bagworm
Subject: What is this? LOL
Location: Orangeburg, NY
July 24, 2013 5:06 pm
This was crawling on the sidewalk and inching along and appeared to be dragging the ”salad” behind it…sort of an insect Carmen Miranda …any ideas? It was about 3~4 inches long…
Signature: Don Slevin
This is a Bagworm, a caterpillar in the family Psychidae. We believe it is an Evergreen Bagworm, Thyridopteryx ephemeraeformis, based on photos posted to bugGuide.
Letter 5 – Bagworm
Subject: What made this?
Location: San Antonio, TX (west side)
July 13, 2014 11:35 pm
Noticed this yesterday while working in the yard. It’s dangling from a live-oak tree. I’ve been here 8 years and never seen one here before, or anywhere else I’ve ever lived.
If you’re the size of a bug I think this is a marvel of construction. As far as I can tell those are very neatly cut or chewed twigs. Notice the hanging apparatus, it almost looks like braid, or rope.
It is approx 3″L x 14/16″ at the widest point. I showed it to a friend asking if he knew what it was, and his reply was, “Mini air-beavers?”
What’s your guess?
Though the thought of mini air beavers is tremendously amusing, this is actually the pupa of a Bagworm, a moth in the family Psychidae. Construction on the bag begins with the young caterpillar and the bag is enlarged as the caterpillar grows.
The Bagworm caterpillar drags around its bag which acts as shelter and camouflage, and eventually the Bagworm caterpillar pupates within the bag after attaching the bag to a brand or fence.
Your Bagworm is in the pupal stage. When it is mature, a winged male Bagworm moth or a flightless female Bagworm moth will emerge.
Letter 6 – Bagworm
Subject: Leafy Caterpillar
Location: Tampa, FL
May 31, 2015 11:18 am
We saw this guy crawling across the sidewalk of a strip mall in Tampa, FL and were wondering what kind of caterpillar it is.
Signature: Nikki D.
Dear Nikki D.,
This is some species of Bagworm in the family Psychidae. Bagworm caterpillars construct a shelter out of the plant material upon which they are feeding that acts as camouflage as well as protection.
According to BugGuide: “Larvae (bagworms) construct spindle-shaped bags covered with pieces of twigs, leaves, etc., and remain in them — enlarging the bags as they grow — until they pupate (also in the bag).
Adult females remain in the bag, emitting pheromones which attract adult males to mate with them.”
Letter 7 – Bagworm
Subject: What’s that bug?
Location: On bushes and on the walls(outside)
November 22, 2015 8:52 pm
Hello bug man:
I found this at home here in Florida and I have no idea what is it. There’s a lot of them in my bushes and on the walls and they are eating the leaves. They are destroying my bushes. What should I do?
Signature: By email
This is a Bagworm, the larva of a moth in the family Psychidae. Here is a matching image from BugGuide. According to BugGuide: “Larvae (bagworms) construct elaborate little cases around themselves of plant debris and other organic matter.”
Letter 8 – Bagworm
Subject: Chrysalis on painted Stucco
Location: Hutchinson Isl. , Ft. Pierce, FL
July 3, 2016 6:35 am
We have had these all over the house since last Autumn. None have emerged as of July. Does anyone know what these are?
This is a Bagworm in the family Psychidae. Caterpillars begin constructing a bag when they first hatch and the material is from the plant upon which they are feeding spun together with silk.
The Bagworm eventually pupates within the bag, sometimes after securing the bag to a surface other than the tree upon which they were feeding. You must have a host tree or shrub near your stucco wall.