Insect of the Month: Rice Weevil (Sitophilus oryzae)

The Rice Weevil larvae do the greatest amount of damage as they eat the inside of grains and seeds, leaving only a husk behind. The adults also have strong chewing mouthparts and will cause damage as well. Detection can be difficult in grains that have recently had eggs laid in them.

After some time, the damage becomes evident as the grains become so light and hollow, that you can easily break them into dust with your fingertips. In heavy infestations, chewing can sometimes be heard. 

What do rice weevils look like?

Rice Weevil Adults: Adults are 2-3 mm (0.125 inches) long, dull reddish-brown to black, having the prothorax pitted with deep, round punctures and with four light spots on the wing covers.

Rice Weevil Eggs: Female Rice weevils will chew a hole into a grain kernel and deposit a single egg.

Rice Weevil Larvae: Larva fully develops inside the whole kernel of grain or dried pasta, eating it away as it grows. By the time it is ready for pupation, the entire inside of the kernel has been eaten away, usually leaving only a thin seed cover.

Rice Weevil Pupae: Pupation also occurs within the kernel of grain.

What is the rice weevil life cycle?

In the Rice weevil life cycle, the female will eat out a cavity in the grain large enough for an egg. She will then use her ovipositor at the tip of her abdomen to lay a single egg in each kernel of grain. After depositing the egg, she will seal off the hole, making detection difficult.

The Rice weevil egg will hatch in about 3 days. The larval stage will take, on average, about 18 days and pupation will take 4 days. The adults will live about 110 days and are strong fliers

Monitoring Guidelines for Rice Weevil (Sitophilus oryzae)

Click on the image or insect name above to view monitoring guidelines for rice weevils. These guidelines include details on Description, Lifecycle, Damage and Detection, Corresponding Products, Fun Facts, and more!

Stay tuned

Next week we are going to be sharing a solution Insects Limited offers when dealing with rice weevils.

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.

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Product of the Month - All Beetle Rice Weevil Kit (IL-700)

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