The maize weevil (Sitophilus zeamais) is a tropical grain pest that thrives in Arizona's hot climate, making it more common here than in cooler states. It is closely related to the rice weevil and attacks corn, wheat, rice, oats, barley, and sorghum. Like other weevils in the Sitophilus genus, maize weevil larvae develop entirely inside individual grain kernels — females bore into the kernel, deposit an egg, and seal the hole. The larva consumes the kernel from within, and the adult chews its way out when mature. Adults are small (3–4mm), reddish-brown to black, with a long snout, and can fly — which helps them spread between grain storage areas.
Controlling maize weevils in Arizona requires the same approach as other grain weevils: discard all infested grain products, vacuum pantry shelves thoroughly, and store all grain in airtight containers. Because maize weevils can fly, check adjacent rooms and cabinets for adults. Inspect all corn-based products — popcorn, cornmeal, grits, and whole corn — as these are the most common infestation sources. Freezing newly purchased grain for 72 hours before storage kills any eggs or larvae present. Pheromone traps are available for Sitophilus weevils and can help monitor for re-infestation.
Arizona's warm climate allows maize weevils to reproduce year-round, with the life cycle completing in as little as 4 weeks at peak summer temperatures. This rapid reproduction means infestations can grow quickly if not addressed promptly. If you find maize weevils in multiple pantry items or in rooms outside the kitchen, a professional inspection is recommended. Pest Control Bros LLC provides stored-product pest control throughout Maricopa, Chandler, Mesa, Tempe, Gilbert, and Casa Grande. Call (520) 424-5244.
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