Rice Weevil
Appearance:
Adult rice weevils are about 1/8 inch long, dull reddish-brown, and usually have 4 faint reddish to yellowish paler marks on the elytra (wing covers). There are numerous round pits on the thorax. Rice weevils have fully developed wings and are able to fly.
The larva is legless, creamy white with brownish-black head, thickened in the middle (humpbacked), and relatively smooth.
Habitat:
The rice weevil female chews a hole into a kernel of grain and lays an egg, sealing the opening with a gelatinous material. Females can lay 300 to 400 eggs in their lifetime but egg-laying is sporadic during the wintertime, with less activity at cooler temperatures. There are 3 to 4 instars (growth stages), which require an average of 18 days for development. The pupa stage requires an average of 6 days (range 3 to 9) and upon transformation, the adult insect will remain within the kernel for 3 to 4 days until it tans (hardens) and matures. The life cycle (egg to egg) may be as short as 32 days in the summer. The adult may live for 3 to 6 months.
In the south, adults fly from stored grain to infest the new grain crop in the filed and the infestation continues through storage. Rice weevils occasionally are delivered to pet shops and super markets in birdseed containing infested sunflower seeds. Therefore, rice weevils are sometime brought into the home in birdseed. It has been recorded attacking corn, wheat, rice, beans, nuts, cereals, rye, buckwheat, stored cotton, wheat products of all kinds, and grapes. In addition, it will feed on apples and pears. Optimum conditions for rice weevil activity are 80 to 86°F, 75 to 90% relative humidity, and grain of 13.5 to 17.6% moisture content. When disturbed, it will draw its legs up to its body and “play possum”. Adults can fly and are attracted to lights.
Diet:
Primarily whole grains, but also beans, nuts, cereals and fruit.
Solutions:
What you can do: Let the buyer beware: Bags of bird seed and packages of whole grain cereal and snack foods should be carefully inspected for evidences of rice weevils and other stored product pests before purchase. If infested products are discovered on shelves, they should be bagged and discarded immediately. The beetles can be removed from activity sites using a vacuum cleaner fitted with a hose attachment.
In commercial settings, infested product should either be removed and discarded or returned / shipped back to the source along with a description of the infestation as being the reason for return.
Professional Solutions:
Once infested product has been removed and the remaining insects and food debris have been vacuumed or wiped clean, a Quik-Kill service technician can perform a crack and crevice treatment to eliminate adult weevils that may be concealed in structural seams and crevices of cabinets and shelving.
In food warehouses and mills infested with rice and granary weevils, the facility may need to be heat-treated, fumigated, or treated with a ULV (fog) application to destroy the adult weevils.
