Species Spotlight: The Rice Weevil (Sitophilus oryzae)
Ethan Estabrook, BCE - Research Associate at Insects Limited
Rice weevil (Sitophilus oryzae) and maize weevil (Sitophilus zeamais) can cause serious damage to stored grains. They are internal feeders and damage grain by boring holes into grain kernels reducing weight, nutrition, and overall quality.
Their movement through a grain mass can spread and encourage mold germination and their excrement leaves behind uric acid that causes grain rancidity. Watch a timelapse GIF of 100 rice weevils in popcorn over a one-year period.
You can see how quickly they damage whole grain kernels and introduce and spread mold shortly thereafter.
Rice Weevil Description
• Adults have prolonged head or snout
• Adults are dark brown with 4 distinct lighter yellowish spots, about 2.5 to 4mm in length
• Adults are able to fly
Rice Weevil Life History
• Females lay 300-575 eggs over a 5-8 month lifespan
• Females individually lay eggs within grain kernels
• Infestation can establish at temperatures as low as 59°F, but development is prolonged
• Optimum development takes place around 84°F at a relative humidity of 70%
Rice Weevil Damage
• Feed on barley, corn, sorghum, rice, rye, and wheat
• Grains with round holes are a sign of infestation by emerging adults
• Can almost complete total destruction of product at high densities
• Infestation can lead to heating and increased moisture levels in grain
Insects Limited, an Insect Pheromone Company
Insects Limited, Inc. researches, tests, develops, manufactures and distributes pheromones and trapping systems for insects in a global marketplace. The highly qualified staff also can assist with consultation, areas of expert witness, training presentations and grant writing.
Insects Limited, Inc. specializes in a unique niche of pest control that provides mainstream products and services to protect stored food, grain, museum collections, tobacco, timber and fiber worldwide. Please take some time to view these products and services in our web store.
