Stored Product Pests

Angoumois Grain Moth

• Order: Lepidoptera   Family: Gelechiidae

• Sitotroga cerealella

• Description: Adults have yellowish-brown wings and have a wingspan of approx. 1/2 inch. Forewings are lighter than hindwings. Larvae are white with a yellow headcapsule

Angoumois Grain Moth

Angoumois Grain Moth Life History

• Female oviposits on grain kernels in cribs

• Once larvae emerge, they eat a hole in the kernel and feed within the kernel

• Larvae pupate within the kernel after chewing an exit hole

• Life cycle takes about five weeks

Angoumois Grain Moth Damage

• Larvae damage grain kernels by feeding inside (can be recognized by round hole in kernel post emergence)

• Found in many types of stores cereal grains

• The larvae infest primarily the surface layer of grain

• Most damage is to corn kernels.

Angoumois Grain Moth Damage

Angoumois Grain Moth Management

• Most effective control is to monitor for holes in the kernels. If noticed, empty the bin as soon as possible.

• If infestation level high, fumigants may be applied, but this technique is not too effective without first covering the crib with a tarp

Flour Beetles

• Order  Coleoptera   Family: Tenebrionidae

• Confused Flour Beetle:  Tribolium confusum

• Red Flour Beetle:  Tribolium castaneum

• Both are know as “bran bugs”

• Description: both are about 1/8inch, flattened appearance, red-brown, elongate body

Flour Beetle

Flour Beetle Life History

• Females lay 300-400 eggs in flour or other food items over a period of 7 months (5-12 eggs/day)

• Larval stage lasts between 22 -100 days

• Adults emerge a week after initiation of pupation

• Complete life cycle requires 7 to 12 weeks, and adults can live up to three years

Flour Beetle Damage

• Both beetles live and breed in damaged grains, especially ones with a high moisture content (above 12%)

• Can infest a variety of products from grains to legumes to milk chocolate

• Infested product can often be recognized by the presence of an odor

Flour Beetle in Grain

Flour Beetle Control

• Sanitize bins properly to try to avoid infestation

• If grain will be stored for more than six months, an insecticide is often applied

• Screen corn for holes or broken kernels before placing in bin

Saw-toothed Beetle

• Order: Coleoptera   Family: Cucujidae

• Oryzaephilus surinamensis

• Description: Adults are dark brown, flat, and elongate.  There are sawtooth projections coming off of the thorax.  Larvae are white or yellow

Saw-toothed Grain Beetle

Saw-toothed Beetle Life History

• Females lay eggs singly or in a small cluster within a food material after they emerge in April

• The lifecycle is often completed in about 50 days

• 6-7 generations per year are common in habitats that are between 85 and 95 degrees F.

• There are fewer generations during the winter

Saw-toothed Beetle Damage

• Prefer to feed on broken kernels, but will feed on undamaged ones as well

• feeding may increase mold growth within bins

Saw-toothed Grain Beetle

Saw-toothed Beetle Management

• Sanitize bins

• Check grains at two week intervals during warm periods. If moldy areas are noticed, grain should be aerated to lower moisture level and temperature

Mealworms

• Order:  Coleoptera    Family: Tenebrionidae

• Tenebrio spp.

• Dark Mealworm & Yellow Mealworm are both pests in Pennsylvania

• Adults are black and about 1/2 inch long. Thorax covered with punctures and wings have longitudinal grooves

Mealworms

Mealworm Life History

• Univoltine

• Adults emerge in late spring

• Females lay eggs over a period of 20-140 days

• Eggs hatch two weeks later

• Larvae feed and molt until winter.  Larvae enter diapause and overwinter

Mealworm Damage

• Mealworms feed externally on grains

• Large larvae can cause serious damage when grains are held for a long time

• Damage is primarily in the form of contamination of product with the insects and their waste products

Mealworm Management

• Sanitize bins

• Grain should be treated with an insecticide if it will be stored for more than six months

Indian Meal Moth

• Order: Lepidoptera  Family:  Pyralidae

• Plodia interpunctella

• Description: Adults have a 1/2 inch wing span.  Wing tips are reddish-brown, rest of wings are light gray or yellow. Larvae are white with brown headcapsules

Indian Meal Moth

Indian Meal Moth Life History

• Potential for 7-9 generations per year under optimal temps

• Female lays between 100 to 300 eggs

• Larvae hatch in 2-14 days (dep. On temperature and moisture)

• Larvae feed on grain germ for a time period between two weeks and a year before pupating

• Adults live for about 15 days

Indian Meal Moth Damage

• Larvae cause most of the damage by feeding on grain germ within the top two inches of grain in the bin

• Value is primarily lost due to contamination of product with insect and insect parts

Indian Meal Moth Damage

Indian Meal Moth Management

• Sanitize bins

• Run grain dryer fan from time to time in order to prevent buildup of insects within the bins

Foreign Grain Beetle

• Order: Coleoptera  Family:  Cucujidae

• Ahasverus advena

• Description: Adults is small and reddish-brown in color. Both front corners of the thorax have a rounded lobe on them

Foreign Grain Beetle

Foreign Grain Beetle Life History

• Females lay eggs on moldy grains (either singly or in a cluster)

• Larvae take about 15 days to develop and then pupate

• Adults live for up to 250 days

Foreign Grain Beetle Damge

• Larvae and adults feed primarily on the mold growing on grains.

• Presence of the mold and the insect can decrease the value of the grain

Foreign Grain Beetle Management

• Clean bins before putting new grain in

• Check bins for mold growth and remove any spots with mold growth if some are found

Weevils on Stored Grains

• Order: Coleoptera   Family: Curculionidae

• Sitophilus spp.

• Common Names: Rice Weevil and Granary Weevil

• Description:Adults vary in color from dull red to black.  Laravae are white, legless grubs

Rice Weevil

Stored Grain Weevil Life History

• Females lay between 300-400 eggs during a 4-5 month time period

• 26 days are required for development from egg to adult in hot temperatures, but takes longer in cool and cold temperatures

Stored Grain Weevil Damage

• Considered to be very destructive to grains

• Rice weevil causes more damage than the others because it is able to fly

• Weevils feed on a variety of stored products, including wheat, corn, macaroni, and oats

• Damage within a bin is often complete (they do not stay only within the top layer of grain)

Stored Grain Weevil Damage

Rice Weevil Damage

Stored Grain Weevil Control

• Sanitize bins

• Get rid of infestation source ASAP

• Use a flashlight when inspecting bins

• Infestations often occur if grains are stored for more than a month during warm weather