COMMON NAME: |
Indianmeal Moth |
SCIENTIFIC NAME: |
Plodia interpunctella (Hubner) |
CLASS/ORDER/FAMILY: |
Insecta |
METAMORPHOSIS: |
Complete |
INTRODUCTION. The
Indianmeal moth was given its common name by an early entomologist (Asa Fitch)
who found it feeding on cornmeal (Indian meal). It is probably the most
encountered 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.
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.
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 tunnel
like 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 birdseed. 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 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.