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COMMON NAME:
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Indian
meal moth
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SCIENTIFIC
NAME:
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Plodia
interpunctella (Hubner)
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CLASS/ORDER/FAMILY:
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Insecta
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METAMORPHOSIS:
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Complete
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INTRODUCTION.
The Indian meal moth also referred to as pantry moths or pantry
pests was given its common name by an early
entomologist (Asa Fitch) who found it feeding on cornmeal (Indian
meal hence Indian meal moth ). It is probably the most encountered
(pantry) pest of stored products
found in the home and in grocery stores in the United States. Of
Old World origin, it is now found worldwide.
RECOGNITION.
Adults with wingspread (wing tip to wing tip) about 5/8-3/4"
(16-20 mm). Wings pale gray but front wing with outer 2/3's
reddish brown with a coppery luster.
(actual size)
Mature larva usually about 1/2" (range 9-19 mm) long. Usually
dirty white but color may vary to a greenish or pinkish or
brownish hue depending on its food, with head and prothratic
plate/shield yellowish brown to reddish brown. With 5 pairs of
well-developed prolegs on abdomen and each bearing crochets
(hooks).
Prespiracular tubercule (wartlike area between spiracle and front
edge of segment) of prothorax with 2 setae (hairs). Tubercule VI
on mesothorax (wartlike area near and above leg) with one seta
(hair). Body without pinnicula (dark or pale wartlike area at base
of hairs or setae) on mesothorax, and 1st 9 abdominal
segments.
Rim around
spiracles of about even thickness.
SIMILAR GROUPS.
- Carpet/tapestry
moth (Trichophaga tapetzella) with basal 1/3 of front
wing dark brown to black, remainder of wing white mottled with
gray and black.
- Other small
moths lack front wing with basal 1/3 pale and remainder dark,
wing span of about 5/8-3/4" (16-19 mm), and/or hind wing
broader than front wing and fringed with long hairlike scales.
BIOLOGY.
Chiefly at night, the female lays 100-400 eggs, singly or in small
groups, on the larval food material during a period of 1-18 days.
Upon hatching, the larva establishes itself in a crevice of the
food material. It feeds in or near a tunnellike case it has webbed
together of frass or silk. The larval period lasts 13-288 days,
depending primarily on temperature and food availability. When the
last instar larva is ready to pupate, it leaves the food and
wanders about until a suitable pupation site is found. There are
usually 4-6 generations per year (range 4-8), with the life cycle
(egg to egg) typically requiring 25-135 days (range 25-305).
HABITS. The
adults cause no damage. The larvae are surface feeders and
generally produce a lot of webbing throughout the infested part of
the materials. They are general feeders and attack grain and grain
products, a wide variety of dried fruits, seeds, nuts, graham
crackers, powdered milk, biscuits, chocolate, candies, dried red
peppers, dried dog food, and bird seed. They are very destructive
wherever dried fruits are stored. Preferred are the coarser grades
of flour such as whole wheat, graham flour, and cornmeal, but they
can breed in shelled or ear corn.
When the larvae
wander about looking for pupation sites in homes, they (pantry
moths) are often
mistaken for clothes moth larvae. Likewise, when the moths are
flying, they are also mistaken for clothes moths. Adults are
attracted to light.
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