| The
facts
Moth larvae can cause considerable damage to stored goods
by feeding or by contamination with their own products,
e.g. webbing and frass. Adult insects are not responsible
for damage as they either feed on liquid food and water
or do not feed at all. The larval byproducts, webbing and
frass, are a particular problem. Webbing can entirely coat
commodities and may be responsible for blocking machinery
and ducts. The problem is exacerbated when webbing becomes
mixed with frass, food and general debris. A major pest
of warehouses and, more recently, retail premises. This
species will infest cereals, fruit, shelled nuts, cocoa
beans, fish, spices and tobacco. In the case of tobacco,
"sweet" varieties are preferred and entire interveinal
leaf areas may be destroyed. Moth infestations are especially
serious where wheat and flour are stored in bulk, although
they
seldom infest goods which are stored in silos. The larvae
themselves are unique and readily identifiable: well-developed
head; clearly segmented body; three thoracic segments, each
bearing a pair of five jointed legs; ten abdominal segments:
numbers 3-6 bear false feet (prolegs), the tips of which
are equipped with crochets; segment ten bears one pair of
claspers. Within 4 days of emergence, the female produces
100-150 eggs which are laid in cracks and crevices. These
hatch in 10-14 days to give larvae which are creamy-white
with dark spots on their sides. They penetrate food, covering
it with webbing as they feed. In colder climates larvae
pass through 4-5 moults to attain full growth when they
are 12mm long, whereupon they will leave the food and wander
for 1-3 days, searching for a dark place in which to spin
a silken cocoon. They may diapause in this state throughout
the winter before pupating in April or May and emerging
as adults in late spring. At room temperature development
takes from 82-206 days.
Where do Moths live?
Moths live throughout the world, except in the oceans. They
inhabit steamy jungles near the equator, and they have even
been found on icecaps in the Arctic. Moths vary greatly
in size. The largest moths are the Giant Hercules of Australia
and the Giant Owl Moth of South America. They have a wingspread
of about 12 inches (30 centimeters). The smallest moths
have wingspreads of about 1/8 inch (0.3 centimeters). These
moths belong to a group called leafminers.
Why keep Moths under control?
The reason Moths are considered a public health pest is
chiefly because they consume and contaminate vast quantities
of food, worldwide, intended for human consumption. With
a 12mm wingspan; upper forewing: well defined, rather sinuate
outer band on grey-buff background. Larval development is
greatly influenced by the environmental conditions of temperature
and food supply. Egg laying commences within 24 days of
the adult's emergence, and up to 350 eggs are laid during
the first 4 days. These hatch 3-17 days later. The larvae
are dirty-white and may be tinged brown or have purple spots.
At 25°C they will be fully grown in 25 days. The larvae
do not diapause. Pupae develop in 12-17 days in the vicinity
of food, and breeding is continuous. Where temperatures
are low the moth overwinters as larvae.
Prevention & Control
The method and timing of control measures against moths
depends upon the species involved. The larvae are frequently
difficult to reach because they are concealed in foodstuffs
or the fabric of buildings and may be obvious only when
they migrate. This is important in order to avoid conditions
suitable for the development of moth infestations. Warehouses
should be constructed so as to ensure maintenance of correct
storage conditions and allow easy cleaning. Cracks and crevices
which might serve as harbourages should be kept to a minimum.
Stacks of commodities should be neatly arranged above the
floor on pallets, with a gap between stacks to allow for
ventilation, regular inspection, cleaning and treatment
with insecticides if necessary; Good packaging is particularly
important to prevent entry of larvae. Spillages should be
removed promptly, and infested goods dealt with immediately
either by fumigation or destruction. Uncontaminated products
should not be stored in the vicinity of infested materials.
In the case of the house and clothes moths, fabrics should
be regularly inspected and cleaned, and alternative breeding
sites, for example birds' nests, removed if possible. It
should be remembered that soiled fabrics make a more acceptable
diet to these insects than clean ones. In order to obtain
the best results, insecticidal control measures should be
integrated with good hygiene.
Treatment
Contact Paramite Pest Solutions
if you suspect you may have a problem and we can advise
you on the best course of action. A visit by our pest control
officer can be arranged. He will carry out a survey and
suggest what action needs to be taken. Adhesive traps are
used for trapping stored product moths. Attractant capsules
containing a pheromone are attached to a sticky surface
on which the moths are caught and which is partially protected
from the environment. The trap is then suspended ca 2-3
m above the floor. They perform best in locations which
are not dusty. Alternatively funnel traps may be used. These
are usually constructed of plastic and incorporate a funnel
system leading to a retaining chamber in which moths are
trapped and killed using a toxicant strip, water or detergent.
Paramite Pest Solutions will take all possible precautions
in the placing of poison baits. Revisits will be made until
the problem is cleared. |
