Homeowners buying mulch to put around shrubs and foundations should make sure they know where the wood originated. Officials in Louisiana say mulch made from trees knocked down during last summer's hurricanes could contain a nasty scourge Formosan subterranean termites.

The Louisiana State University AgCenter says it has taken steps to prevent the spread of the termites in mulch. It's a concern, however, because so many trees were destroyed in Hurricanes Katrina and Rita, and thousands were turned into mulch to help get rid of debris.

"Yes, Formosan subterranean termites are found in the parishes affected by the hurricanes and will get in mulch. However, the Louisiana Department of Agriculture and Forestry (LDAF) in Louisiana imposed a quarantine for the Formosan subterranean termite on October 3, 2005, in Calcasieu, Cameron, Jefferson, Jefferson Davis, Orleans, Plaquemines, St. Bernard, St. Charles, St. John the Baptist, St. Tammany, Tangipahoa and Washington parishes," the AgCenter said in a release.

Provisions of the quarantine imposed by the LDAF include:

• Movement of wood or cellulose material is prohibited unless either (1) it is fumigated or treated for Formosan subterranean termites and is approved for movement by the commissioner or his designee(s) or (2) written authorization is given by the commissioner or his designee(s) for the movement of untreated wood or cellulose material from the quarantined parishes.

• Temporary housing cannot be moved from the named parishes until written authorization is given by the commissioner or his designee(s).

• All architectural components (beams, doors and salvaged wood) cannot be sold or placed in any structure in any parish until the architectural components are fumigated or treated for Formosan subterranean termites.

• Additionally, it is strongly recommended and urged that all new construction and reconstruction of structures in the quarantined parishes use termite-resistant materials. Termite-resistant materials include pressure-treated wood (borates, ammonical copper quat or copper azole) or non-cellulose materials.

The quarantine is in effect until it is rescinded by the commissioner of agriculture. If a waiver of a requirement or an authorization to carry out one of the prohibited acts is granted, it does not rescind or modify the quarantine.

The quarantine should cover most of the trees lost in the storms, but any trees shredded into mulch during September before the quarantine was imposed would not have been covered.

Additionally, black market operators shredding the trees into mulch in violation of the quarantine may try to sell their tainted product to volume distributors.