Sawtoothed Grain Beetles
Facts, Identification & Control
Oryzaephilus surinamensis (L.)
The sawtoothed grain beetle is a major pest of stored food products in homes and commercial facilities. It is about 2.5 to 3 mm long. The body is flat. There are six tiny projections on each side, just behind the head. These projections give the beetle its name. It helps to use a magnifying glass to see them.
Behavior, Diet & Habits
The sawtoothed grain beetle is not attracted to light and it does not fly. There is a related insect, the merchant grain beetle. The fact that the merchant grain beetle can fly is used as a way to tell them apart.
The sawtoothed grain beetle’s scientific name is Oryzaephilus surinamensis (L.). It means “rice-loving from Suriname.” The name came from the fact that the first specimens to be named came from Suriname.
The sawtoothed grain beetle does not infest whole grain. Its flat body allows it to enter tiny cracks and infest broken kernels. It can also penetrate packages in homes and stores. It feeds on cereal, flour, pet food and birdseeds. It also feeds on nuts, spices, drugs, chocolate and tobacco.
The female beetle deposits eggs in cracks in food or on ground food, like flour. When the eggs hatch, the larvae feed and grow. When the larvae are ready to change to adult beetles, they make a cocoon from food particles. In warm, humid conditions, the entire life cycle, from egg to mature adult, takes about two months. There can be several generations per year.
Signs of a Sawtoothed Grain Beetle Infestation
Homeowners with sawtoothed grain beetles usually detect their presence when they find small beetles in pantry products or crawling on surfaces like counters or shelves.
Inspection and cleaning are key steps in eliminating sawtoothed grain beetles. Empty cabinets and pantries and check every package. Throw away infested food. Vacuum the empty shelves to remove any insects and food particles. Store new food products in tightly sealed glass or plastic containers.
Check areas where pet food and birdseed are stored. An infestation in the kitchen could have come from the birdseed in the storeroom or the pet food in the garage. Store pet food in containers with a lid.
Insecticide application is the final step. The application should be made into cracks and crevices. The object is to eliminate any insects that might be hiding. To avoid misapplication, call the local pest control professional.