Angoumois grain moth is second only to the rice and granary weevils in
its importance as a pest of stored grain in the United States. It attacks
grains maturing in the field as well as in storage. Infested grain in
storage has a sickening taste and smell that make it unpalatable. Only
whole grain is attacked, so other grain products are safe (Linsley and
Michelbacher, 1943). Angoumois grain moths can infest the ripening maize
on the fields and are thus carried into the storerooms. The larva lives
inside the grain kernel and is therefore difficult to spot (so-called
"inner infestation").Besides grain they also infest pulses and seeds.
inside wheat kernel
The adults are small, buff to grayish or yellowish-brown moths, with a
wingspread of 13 to 17 mm. The size of the adult depends on how much food
the larva has consumed. The hindwings narrow down to a point apically,
and are heavily margined with long hairs.
moth on maize
Cycle: The males and females come
together using identified pheromones (specific aromatic attractant substances).
Each female lays an average of about 40 tiny white eggs on or
near the grain, and in 4 to 8 days these hatch into minute, white larvae
that bore into the kernels of barley, rye, corn, oats and wheat. The larvae
are pale yellowish when mature, with a yellowish-brown head, and are about
5 mm long when full grown. They have poorly developed abdominal prolegs.
The larva passes through 3 instars in about 3 weeks, but may hibernate
before changing to a reddish-brown pupa in the spring. Pupation takes
place in a silken cocoon in the feeding cavity in the kernel. There are
2 to 4 generations a year. Ideal temperature for development is 30-32°C
at a relative humidity of 75%.
of damage to wheat
only succesful way to treat this problem is to fumigate, this is because
the problem is hidden in the form of the larvae until the population
of adults gets to such a point as
it becomes obvious. Fumigation will kill the larvae and adults in one
go. Another way of controlling the adults is to use pheromone traps,
which continue to be developed and refined by various companies around
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