Plaster bagworms (Phereoeca uterella) are common household pests. These insects are identified by their distinctive, flattened, gray, seed-like cases, which they carry. Understanding their origins and how they enter homes can help in managing their presence.
The Plaster Bagworm’s Natural Environment
Plaster bagworms thrive in warm, humid outdoor environments, such as those found in Florida. They are often found in sheltered areas like under eaves, on tree trunks, or within spiderwebs. The larvae construct protective cases from silk, incorporating bits of dirt, sand, and other debris from their surroundings.
In their natural habitat, these larvae primarily feed on spiderwebs and insect remains. They also consume decaying organic matter, including fungi, lint, dust, and animal-based fibers like wool. This diet allows them to survive in various environments where such materials accumulate.
How Plaster Bagworms Enter Homes
Plaster bagworms enter indoor spaces through several common pathways. They can get in through small cracks and gaps around windows, doors, or in a structure’s foundation and walls. Poorly sealed roof spaces or vents also serve as potential entry points.
Adult plaster bagworm moths are attracted to light sources, such as outdoor porch lights. This draws them close to a home’s exterior, increasing the likelihood of eggs being laid near entry points or moths finding their way inside. Once indoors, female moths can lay up to 200 eggs in secluded, protected areas like crevices or hidden corners.
Larvae may also be carried into homes on infested items previously stored outdoors, such as used furniture or old fabrics. Their preference for moist environments draws them to high-humidity areas like bathrooms, basements, and laundry rooms, which can further facilitate their entry and establishment.
Recognizing Plaster Bagworms
Identifying plaster bagworms inside a home is straightforward due to their unique appearance. The most recognizable stage is the larva, which resides within a flattened, oval-shaped case. This case is made of silk and camouflaged with materials like plaster, sand, lint, or other debris from its surroundings. It typically measures between 1/4 to 3/4 inches long and resembles a pumpkin or watermelon seed.
The larva remains mostly hidden within its case, extending its body to move and feed. It has openings at both ends, allowing it to switch directions as needed. These cases are commonly found adhered to walls, ceilings, and other surfaces in various indoor locations, including closets, under furniture, in basements, and attics, especially in undisturbed or humid areas.
Keeping Plaster Bagworms Out
Preventing plaster bagworm infestations involves reducing their access and eliminating attractive conditions. Sealing cracks, gaps, or holes in the home’s exterior, including around windows and doors, can block potential entry points. Regularly inspecting and maintaining weather stripping is also useful.
Maintaining proper indoor humidity levels is important, as plaster bagworms thrive in damp conditions. Using dehumidifiers or air conditioners, especially in moisture-prone areas like basements and bathrooms, creates an environment less favorable to these pests. Keeping indoor temperatures moderate can also deter them.
Consistent cleaning and vacuuming remove food sources such as dust, lint, and cobwebs, which are vital for larvae survival and case construction. Wiping down surfaces and ensuring attics and crawl spaces are clean and free of decaying organic matter reduces a home’s appeal to plaster bagworms.