Plant Clinic

Plaster bagworms love to eat spider webs

 

More information

Hunsberger


dade@ifas.ufl.edu

Q.What are those tiny cocoons that cling to the walls inside?

K.F., Pinecrest

What you are describing is a caterpillar called the plaster bagworm, which is very common and generally harmless. The caterpillar lives in a gray, flattened, watermelon seed-shaped case about a half-inch long. The case is constructed of silken fiber and sand particles, lint and other debris. It has a slit-like opening at each end, which lets the larva (caterpillar) move around and feed from either end. Plaster bagworms are easily seen on light-colored walls.

Bagworms can also be found on outside walls and attached to the undersides of patio furniture, and in garages.

Plaster bagworms mainly feed on spider webs, however, they will also feed on fabrics made of natural fiber such as silk. Usually bagworms don’t damage anything indoors unless you allow them to crawl onto fabric. Since they move very slowly, it is easy to keep them away from clothing. If you find some on your indoor walls, check your closets and dressers for this insect and remove any you find.

They enter homes through crevices around doors and poorly sealed windows.

To control the plaster bagworms indoors, good housekeeping is important, especially regularly removing spider webs. Vacuum or sweep down and remove any spider webs and bagworm cases. Insecticides do not control this insect. Place weather-stripping around doorways, especially over the threshold and sliding glass window tracks to keep them from entering your home.

Bagworms on exterior walls cause no damage but can be swept or picked off and disposed. It is much better to sweep spider silk off walls since power washing them may damage paint or stucco.

Insect Samples

Send undamaged (live or dead) insects in a crush-proof container such as a pill bottle or film canister with the top taped on. Mail them in a padded envelope or box with a brief note explaining where you found the insects.

Do not tape insects to paper or place them loose in envelopes. Insect fragments or crushed insect samples are almost impossible to identify.

Send them to the address of your county extension office, found in the blue pages in the phone book under county government.

Adrian Hunsberger is an entomologist/horticulturist with the UF/IFAS Miami-Dade Extension office. Write to Plant Clinic, 18710 SW 288th St., Homestead, FL 33030; e-mail aghu@ifas.ufl.edu.

Read more Home & Garden stories from the Miami Herald

Miami Herald

Join the
Discussion

The Miami Herald is pleased to provide this opportunity to share information, experiences and observations about what's in the news. Some of the comments may be reprinted elsewhere on the site or in the newspaper. We encourage lively, open debate on the issues of the day, and ask that you refrain from profanity, hate speech, personal comments and remarks that are off point. Thank you for taking the time to offer your thoughts.

The Miami Herald uses Facebook's commenting system. You need to log in with a Facebook account in order to comment. If you have questions about commenting with your Facebook account, click here.

Have a news tip? You can send it anonymously. Click here to send us your tip - or - consider joining the Public Insight Network and become a source for The Miami Herald and el Nuevo Herald.

Hide Comments

This affects comments on all stories.

Cancel OK

  • Marketplace

Today's Circulars

  • Quick Job Search

Enter Keyword(s) Enter City Select a State Select a Category