INTRODUCTION
This
species is less commonly encountered and of far less economic
importance than the webbing clothes moth. Its common name comes
from the silken tube/case spun by the larva and which is carried
about wherever the larva goes. The casemaking clothes moth is
worldwide in distribution, but is more common in the southern
United States
.
RECOGNITION
Adults measure about 3/8-1/2” (10-14 mm) from wing tip to wing tip, both wings long and narrow. Body and wings
buff to golden with brownish tinge, except for 3 dark spots on each front wing which may be indistinct or rubbed
off with age. Hind wing fringed with long hairs. Eyes
wider than space between them.
Mature
larva up to 3/8” (10 mm) long. Whitish except
for brown head and dorsal divided shield plate on prothorax. With 1 distinct ocellus on each side. Setae (hairs) IV and V (near and below spiracle)
on 7th abdominal segment about same distance apart
as distance from either to spiracle. Prolegs on abdominal
segments 3-4-5-6 and 10 (anal/last segment), with crochets (hooks
on ends) arranged in single complete ellipse on prolegs 3-6.
SIMILAR GROUPS
(1) Webbing clothes moth (Tineola bisselliella) adult lacks 3 dark
spots on wing, has reddish tuft on head. (2) Carpet/tapestry
moth (Trichophaga tapetzella)adult with basal/inner 1/3 of front
wing dark, remainder white mottled with dark specks. (3)
Angoumois
grain moth (Sitotroga
cerealella) adult hind wing with tip abruptly narrowed towards
front margin, hair fringe on hind margin/edge about as long
as wing is wide, whitish stripe running from base to beyond
center of wing. (4) Mediterranean flour moth (Anagasta kuehniella) adult front wing
gray with black cross lines, wing span ¾-1” (20-25 mm). (5)
Indianmeal moth (Plodia
interpunctella) adult front wing with basal/inner 1/3 buff
colored, outer 2/3’s coppery brown, wing span 5/8-3/4” (16-19
mm). (6) Other moths generally much longer, attracted
to light.
DAMAGE AND SIGNS OF INFESTATION
Silken cases which are cigar-shaped, open-ended, 1/16-3/8”
(1.5-10 mm) long, with pieces of infested material incorporated
into the case, and usually attached to the material at one end,
contain the larva. Surface feeding/grazing in irregular furrows
or holes if infestation severe. The case-containing the pupa
is usually located in a crack or crevice, not on the infested
material.
BIOLOGY
Females mate on the day they emerge as adults and can start laying eggs
the next day. They lay an average of about 37-48 eggs (range
8-83) singly on suitable larval food. The eggs hatch in 4-7
days and the larva wanders about for 24 hours. The larval stage
lasts about 33-90 days depending on temperature and humidity,
during which there will be 5-11 molts. The mature larva seeks
a sheltered place to pupate, and pupation lasts about 9-19 days
depending on the temperature. Developmental time (egg to adult)
takes from 46-116 days. Female adults live about 3-8 days and
males live about 3-5 days.
HABITS
Casemaking
clothes moth larvae attack primarily materials of animal origin
and secondarily those of plant origin. Animal-origin materials
include feathers, wools, rugs, furs, mummified carcasses, taxidermy
mounts, and piano felts. Plant-origin materials include tobacco,
various herbs and seasonings, hemp, various plant-based drugs,
linseed, almonds, saffron, etc. It is particularly a pest of
feathers/down and hair/fur.
The
larvae moves by extending its head and thoracic legs out of
its case and then drags the case along. It can feed from either
end of the case. The larva usually grazes here and there causing
only surface furrows but may occasionally cause holes by feeding
in one place for some time. It rarely spins silk on the material.
When it is ready to pupate, the larva seeks a protected place,
such as a crack or crevice which is usually off the infested
material.
Adults
do not feed. They shun light, not being attracted to lights
as are most moth species. The males are smaller and are active
fliers whereas, the females are sluggish
and fly only short distances.
CONTROL
The key to
control is proper identification, a thorough inspection, good
sanitation, and pesticide application when required. Refer to
this section under the general treatment of fabric and paper pests for details.
If
the source(s) of the infestation cannot be found in the usual
places check the air ducts and especially the cold air return.
If this is a problem area, the ducts should be professionally
cleaned. If pets are or have been present,
check where pet hair may accumulate such as behind and under
baseboards, between cracks of
flooring, etc.
