Clothes Moths: Identification and control in the Home
Quick Facts...
Female moths lay their eggs within one to three
weeks after they emerge. Eggs are glued to woolen threads so that they are not
easily dislodged. The eggs do not remain dormant for long periods, although
hatching is delayed by cool temperatures. It is a myth that eggs can remain
dormant for long periods and suddenly produce new infestations.
The caterpillar (larva) stage feeds on wool soon
after egg hatch. Often they construct a silken tube and feed in the vicinity of
this shelter. Other times the larvae may continue to move across the fabric and
only produce scattered patches of silk on which it rests.
The length of time that the larva feeds varies
greatly. It depends on factors such as temperature, humidity and the quality of
the woolens as food. Under ideal conditions, this stage may be completed in as
little as five weeks; or it can take up
to two years. When full grown, the larva spins a smooth case of silk and pupates
within. It emerges from this stage as an adult moth in about 2 1/2 weeks. Mating
and egg laying begins almost immediately after adults emerge from the pupal
case. Adult moths do not feed and die within a month.
Control
The best way to avoid problems with
clothes moths is through prevention. Woolens and other susceptible fabrics
should be dry cleaned or laundered before being stored for long periods.
Cleaning kills any eggs or larvae that may be present and also removes
perspiration odors that attract the pests.
Articles to be stored should be
cleaned and then packed in tight-fitting containers with moth balls or flakes
containing paradichlorobenzene (PDB) or napthalene. Neither PDB or napthalene
will repel clothes moths or prevent them from laying eggs -- the vapors from
these materials are lethal to clothes moths, but only when maintained at
sufficient concentrations. In order to achieve these levels, the vapors must
be tightly confined with the items you wish to protect. Effective concentrations
can best be achieved by first sealing susceptible items (with the manufacturers'
recommended dosage of moth crystals) in large plastic bags, and then storing the
bagged articles in tight-fitting trunks, boxes or chests. Contrary to popular
belief, cedar closets or chests are seldom effective by themselves, because the
seal is insufficient to maintain a lethal or repellent concentration of the
volatile oil of cedar. Note: Cedar Oil can be purchased and the cedar reoiled.
Also there are other natural substances like Lavandin Oil that can be used.
Controlling existing infestations of
clothes moths requires patience and a thorough inspection to locate all
potential sources of infestation. The source may be an old woolen scarf in the
back of a closet, a fur hat in a box, or a remnant of wool carpeting up in the
attic. Even piano or organ felts may be the source. Infested items should be
thrown out, laundered or dry cleaned.
Vacuuming effectively removes larvae
which are already present as well as hair and lint which could support future
infestations. Be sure to vacuum the edges of carpets, along baseboards,
underneath furniture, inside closets and other "quiet" areas where clothes moths
prefer to feed. Be sure to empty
your vacuum outside after use to prevent your vacuum cleaner now becoming the
new source of the moths.
Insecticide applications directed into infested areas are often useful as a supplement to good housekeeping. Products containing active ingredients such as pyrethrum, allethrin, chlorpyrifos and permethrin are effective. Sprays may be applied to carpets (especially along and beneath the edge adjacent to the baseboard), underneath furniture and other likely areas of infestation where prolonged contact with humans is unlikely. Clothing and bedding should not be sprayed with household insecticides and should be removed before treatment.