Sawtoothed Grain Beetle


Sawtoothed Grain Beetle – Oryzaephilus surinamensis (Linnaeus)

Sawtoothed Grain Beetle can be found in: All 50 States

Color: Reddish-brown
Legs: Six
Shape: Flattened-Oval
Size: 1/10 inch
Antennae: yes
Flight: no

Name comes from the sawtooth-like projections around the thorax.
They do not bite or sting humans or pets, spread disease, or feed on or damage the house or furniture.
These insects have running legs (ambulatory) much like cockroaches and penetrate “tightly sealed” packaging.

They lay eggs singly or in small batches in the food material where the life cycle is completed. Adults usually live about 6 to 10 months, with some living as long as 3 years and 3 months. Female sawtoothed grain beetles usually emerge in April and lay an average of 300 eggs. Egg laying begins about 5 days after emergence and continues up to 3 to 4 weeks. Eggs hatch in about 8 days, larvae mature in 37 days, and pupa about 67 days. The life cycle can be completed in 51 days or as early as 27 to 35 days in Washington, D.C.  There may be as many as 6 to 7 generations under warm conditions of 85 degrees F to 95 degrees F and 70-percent relative humidity, with fewer generations throughout the winter months. Adults remain active and feed. The sawtoothed grain beetle prefers cereal-based products.

Sawtoothed grain beetles are common stored-food product pests that infest cereals, cornmeal, cornstarch, popcorn, rice, dried fruits, breakfast foods, flour, rolled oats, bran, macaroni, sugar, drugs, spices, herbs, candy, dried meats, chocolate, bread, nuts, crackers, raisins, dried dog and cat food, and other foodstuffs, making them unsalable and unpalatable. These beetles are capable of chewing into unopened paper or cardboard boxes, through cellophane, plastic, and foil wrapped packages. Once inside, populations build up rapidly often spreading to other stored foods and into food debris accumulated in the cupboard corners, cracks, and crevices. Sometimes all life stages (egg, larva, pupa, and adult) may be found.

These insects contaminate more food than they consume, and usually are discovered leaving the infested food to crawl about the house. Adults and larvae are external feeders, feeding on finely divided food particles and not whole grains.

The simplest and most effective control measure is to locate the source of infestation and quickly get rid of it. Use a flashlight or other light source to examine all food storage areas and food products carefully. Dispose of heavily infested foods in wrapped, heavy plastic bags or in sealed containers for garbage disposal service, or bury deep in the soil if permitted, practical, and regulations allow. If you detect infestations early, disposal alone may solve the problem.