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 4.4.1.3 Martesia. Martesia, also called Pholads, rock borers or rock-burrowing
clams, resemble clams. They have a pear-shaped body, which is entirely encased within the bivalve
shell even in adult form. Martesia are generally not over two and one-half inches in length by one
inch in diameter. Like the genera Teredo and Bankia, Martesia become imprisoned within the wood.
Martesia can bore in wood, clay, soft rock, shells, plastic and even poorer grades of concrete. The
surface entrance hole is about 1/4 inch in diameter, and thus easier to detect than those of Teredo
and Bankia. The bore holes may be two to two and one-half inches deep and up to one inch in
diameter. Thus, most of the damage is close to the wood surface. The diameter of the hole in-
creases as the organism develops and increases in size.
Martesia cause the most serious damage in tropical waters. On the east coast they are found from
South Carolina southward and become economically destructive in Florida. They cause serious
damage in Hawaii and Mexico. They are also reported to be found on the Oregon beaches, but are
not a serious pest there.
Martesia attacks can be precluded by treating with 20 to 25 pounds of marine-grade creosote or
creosote-coal tar per cubic foot of wood or by treating with 1.0 to 1.5 pounds of ammoniacal copper
arsenate (ACA) or copper chrome arsenate (CCA) per cubic foot of wood; dry; and with 20 pounds
creosote or creosote-coal tar per cubic foot of wood (dual treatment).
4.4.2 Crustacea.
4.4.2.1 Limnoria. Limnoria, also called gribbles, are serious marine pests that
can cause extensive damage. However, their damage is generally visible and thus not as spectacular
as the shipworms. Furthermore, one species, Limnoria tripunctata (Menzies), found in temperate
and subtropical regions, is tolerant of creosote. The other two species L. lignorum (Rathke), found
worldwide in cool to temperate climates, and L. quadripunctata (Holthuis), found in temperate
waters of the Pacific coast, are not creosote tolerant.
Limnoria reproduce by means of eggs carried in a brood pouch on the underside of the body. Be-
tween 6 and 17 eggs are contained within a single brood. When hatched within the parent burrow,
the young differ from the adult only in size, and are able to bore at once. The mature adults are one-
eighth to one-fourth inch long. They are one-third as wide and resemble a wood louse or sow bug.
The body is segmented and has seven pairs of legs with sharp hooked claws which enable it to move
and to cling firmly to a wood surface. It also has a thin platelike appendage (gills) which is used for
respiration and limited swimming. The ability to swim allows the animal to leave its burrow at will,
and to move to new wood sources. The mouth parts include a pair of strong mandibles designed for
chewing wood. The wood is used for food along with other marine fungi and possibly bacteria.
The body ends in a broad tail which is used to close the burrow to intruders.
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