Stored Product Pests

Stored Product Pests

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Stored product pests are a major concern in foods and other sources. Typically found in mills, warehouses, processing plants, homes and even retail stores, stored product pests contaminate more foods then they can consume. The best way to control stored product pests is the locate the product in which they are contaminating and to dispose of it quickly and correctly. General pests control services may be applied to the areas of concern after disposal of the infested product, but generally the infestation will slow down considerably once you remove their food source.

Now, lets take a deep dive into the most common stored product pests that are commonly found in eastern North Carolina.

Stored product pests are broken down into four categories: Internal Feeders, External Feeders, Scavengers and Secondary pests.

Internal Feeders:

The rice weevil is the most common and destructive pest of stored grains due to their ability to fly. Adults are reddish brown and about 1/8 inch long with four light red or yellow spots on the wing covers and punctures on the pronotum are round. The female bores a hole into the grain kernel, deposits a single egg then seals the hole with a gelatinous fluid. The larval and pupal stages are spent inside the grain while the female exits through an abnormally shaped hole.

The granary weevil is chestnut brown or black beetle and closely resembles the rice weevil. It can be distinguished due to lack of markings on the back, cannot fly and the punctures are oval shaped.

Check out this boxed lasagna noodle infested with weevils:

The angoumois grain moth is the next most important internal feeder. It is commonly found in whole kernels of corn, wheat and other grains and seeds. Sometimes found in decorative corn or boxes containing seeds as well as bird seed. Eggs are laid on or near grain either in the field or after harvest. Upon hatching, the larvae bore into the kernels of grain and feed on the inside. When mature, the larvae eats its way out and leave a small trap door opening behind. The adult is small and yellowish white with pale front wings and the back wings are pointed and fringed.

The lesser grain borer is dark brown, cylindrically shaped and about 1/8 inch long. The head is hidden when seen from above. The eggs are laid singly or in clusters in the grain mass, the larvae may enter the kernels and develop within or may feed exclusively externally which leaves flour-like dust behind. May bore into other articles such as books or wood.

External Feeders:

The drugstore beetle which gets its name from infesting pharmaceutical products, closely resembles the cigarette beetle but without the hump-backed appearance. It is brown, cylindrical and has distinct longitudinal lines on the wing covers. The larva is grub shaped or c-shaped and nearly white in color. Along with pharmaceutical products, the drugstore beetle will infest flour, breakfast cereals, kibbled dog food and pretty much any food it can get into.

The cigarette beetle aka the tobacco beetle gets its name from being an important pest of stored tobacco. It can be a serious pest to other products such as rice, seeds, dried plants, books and more! The adults are light brown and fly readily. Females lay eggs over a period of three weeks in newly harvest tobacco or other food items. Active during the evening hours. The larvae are similar to the drugstore, but the body hairs are longer giving it more of a fuzzy appearance.

The Indianmeal moth are known for their silken cocoons when ready to pupate. It is found in nearly any stored food product, will feed in or near leaving frass and extensive webbing matted over the surface of food products on which it feeds. Commonly mistaken for clothes moths, the adults have front wings that are tan on the front third and reddish brown with a coppery luster on the back two-thirds. Adults only live for about two weeks which is why when you encounter a product infested with Indianmeal moths, it is best to quickly get rid of the product and allow two weeks to let the adults to die off. During the day, Indianmeal moths can be found resting in poorly lighted areas. If disturbed, will fly in zig-zag patterns. The larvae do most of the damage when it comes to stored product pests. The Indianmeal moth larvae are 1/2 inch long, dirty white and may have an occasional tint to it. Feeds on a variety of grains and grains based foods including seeds, powdered milk, dog food, crackers, nuts, chocolate and more! Most common stored product moth in home.

There are other external feeders common to this area: cadelle and cabinet or trogoderma beetles, but we won't dive into those this go around.

Scavengers:

The red flour beetle is a common pest to the southern states. The confused flour beetle is primarily a pest of the northern states. The two pests have extremely similar appearance and habits. Both are reddish brown and about 1/8 inch long. The antennae of the confused forms a four-segmented club whereas the red forms a three-segmented club. The larva is yellowish to white except for the darkened mandibles. Due to its small size, it can work its way into any size container and feeds off a wide variety of food stuff. Primarily interested in flour, dried fruits, spices, ect... The major difference between the two pests: confused flour beetles do not fly; whereas, the red flour beetle can fly.

The sawtooth and merchant grain beetles are another stored product pest that are extremely similar. In order to determine the pest, the PMP (pest management professional) must closely examine the small projections on either side of the head. The sawtooth projections are curved and wide, whereas the merchant has pointed and narrow projections. Also, the merchant grain beetle flies; whereas, the sawtooth does not fly. These pests are small brownish beetles with six sawtooth like projections on either side of the thorax. The larva nibbles on finely divided food particles and can be found with other stored product pests that feed on grain. Commonly found in breakfast cereals, flour, chocolate, dried fruit and more!

The Mediterranean flour moth adults have a wingspan of about 1 inch. The front wings are pale grey with wavy black lines, and the hind wings are dirty white and rounded at the ends. The Mediterranean flour moth is known for its characteristic pose when resting: the front of the body is raised giving the wings a downward slope. The larvae spin silken threads as they move about and can be found away from the infested product. Commonly infests items such as flour, nuts, dried fruits and more.

These are only a few of the common stored product pests that pest control professionals encounter. There are a multitude of other pests that will be discussed at a later time including the mealworms and the red-legged ham beetle. When encountering any of these stored product pests, it is best to locate the source and dispose of it in a timely manner. Be sure the area is cleaned where it was found and be sure other products of similar source are properly sealed to prevent re-infestation. It is common to still see a couple lingering around once you have removed their food source. Unsure if you are battling a stored product pest infestation? The pests are still lingering around after the food source was removed? Contact Pestco Exterminating today to have one of our highly trained pest control professionals inspect your home!

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