The Maize Weevil (Sitophilus zeamais) is a tropical grain weevil so closely related to the Rice Weevil (S. oryzae) that the two were long considered the same species. Both are small (1/8 inch), dark reddish-brown with four pale spots on the wing covers, have an elongated snout, and can fly. The Maize Weevil is generally slightly larger than the Rice Weevil and has a stronger preference for corn (maize), though it also attacks wheat, rice, sorghum, and other whole grains. A key distinction from the Rice Weevil is that the Maize Weevil can attack corn kernels both in the field (pre-harvest) and in storage — making it a more significant agricultural pest. In Arizona, the Maize Weevil is found in stored corn, feed corn, and popcorn, and is a significant pest in agricultural storage facilities and homes that store corn products. Like the Rice Weevil, larvae develop entirely inside grain kernels, making infestations difficult to detect until adults emerge. In Arizona's warm climate, the Maize Weevil can complete a generation in 4–5 weeks.
👁Warning Signs
Small (1/8 inch) dark reddish-brown beetles with elongated snout and four pale spots on wing covers found in stored corn, popcorn, or whole grains. Round exit holes in corn kernels. Hollow kernels. Adults may be found flying near grain storage.
⚠Health & Property Risks
Attacks corn both in field and in storage. Destroys grain kernels from the inside. Significant losses in stored corn, wheat, and whole grains. Can fly. Rapid reproduction in Arizona's warm climate.
Prevention Tips
Store corn and whole grains in airtight containers. Inspect purchased grain. Freeze new grain purchases for 1 week. Rotate grain stocks. Inspect field corn before harvest.
🛡Professional Treatment
Discard all infested grain. Freeze suspect grain at 0°F for 1 week. Airtight storage for remaining grain. Clean and vacuum storage containers.
Frequently Asked Questions — Maize Weevil
The Maize Weevil (Sitophilus zeamais) is dark reddish-brown; four pale reddish-orange or yellowish spots on wing covers and typically measures 1/8 inch (slightly larger than Rice Weevil); elongated snout. The Maize Weevil (Sitophilus zeamais) is a tropical grain weevil so closely related to the Rice Weevil (S. oryzae) that the two were long considered the same species. Both are small (1/8 inch), dark r.
The Maize Weevil poses a moderate risk. Attacks corn both in field and in storage. Destroys grain kernels from the inside. Significant losses in stored corn, wheat, and whole grains. Can fly. Rapid reproduction in Arizona's warm climate.
In Arizona, maize weevils are most often encountered in the following situations: Small (1/8 inch) dark reddish-brown beetles with elongated snout and four pale spots on wing covers found in stored corn, popcorn, or whole grains. Round exit holes in corn kernels. Hollow kernels. Adults may be found flying near grain storage.
The Maize Weevil is most active during: Year-round indoors; most active in warm months; thrives in Arizona's warm climate; can attack field corn pre-harvest. Arizona's warm desert climate can extend activity periods compared to other states, so year-round vigilance is recommended in the Phoenix metro and surrounding areas.
Store corn and whole grains in airtight containers. Inspect purchased grain. Freeze new grain purchases for 1 week. Rotate grain stocks. Inspect field corn before harvest.
Discard all infested grain. Freeze suspect grain at 0°F for 1 week. Airtight storage for remaining grain. Clean and vacuum storage containers.
Left unchecked, Maize Weevil infestations can cause significant structural or food-storage damage over time. Attacks corn both in field and in storage. Destroys grain kernels from the inside. Significant losses in stored corn, wheat, and whole grains. Can fly. Rapid reproduction in Arizona's warm climate. Early detection and professional treatment are the most cost-effective approach — contact Pest Control Bros for an inspection at the first sign of activity.
Dealing with Maize Weevil?
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