Characteristics of the grain weevil
The grain weevil is a synanthropic species that only occurs in warehouses where it feeds on grain. It does not occur in nature and its spread depends on the transport of grain by humans, as the weevil cannot fly.
Morphology
The grain weevil is between 2 and 5 mm long, depending on the storage conditions. The size of the insect depends on the temperature, humidity and type of grain in which the larva develops – they are smaller in smaller grains such as millet or sorghum and larger in larger grains such as corn. The body of the weevil is elongated, cylindrical and dark brown, with dotted covers and a chitinous carapace that makes it crush-resistant. The lack of membranous wings prevents it from flying. The head is elongated into a long snout with a well-developed mouthpart and a pair of antennae.
Granary Weevil
The granary weevil (Sitophilus granarius, Sitophila granaria, Calandra granaria) is a beetle from the weevil family. It is one of the most dangerous storage pests, feeding on cereal grains and causing significant damage to stored goods.
Characteristics of the grain weevil
The grain weevil is a synanthropic species that only occurs in warehouses where it feeds on grain. It does not occur in nature and its spread depends on the transport of grain by humans, as the weevil cannot fly.
Morphology
The grain weevil is between 2 and 5 mm long, depending on the storage conditions. The size of the insect depends on the temperature, humidity and type of grain in which the larva develops – they are smaller in smaller grains such as millet or sorghum and larger in larger grains such as corn. The body of the weevil is elongated, cylindrical and dark brown, with dotted covers and a chitinous carapace that makes it crush-resistant. The lack of membranous wings prevents it from flying. The head is elongated into a long snout with a well-developed mouthpart and a pair of antennae.
Frequently asked questions
What is the granary (cereal) weevil and why is it considered a serious storage pest?
The granary weevil (Sitophilus granarius) is a beetle from the weevil family. It is considered one of the most dangerous storage pests because it feeds on cereal grains and can cause significant damage to stored goods.
How can I identify a granary weevil (size, color, and key features)?
Granary weevils are typically 2–5 mm long, with size depending on storage conditions. They are dark brown, elongated and cylindrical, with dotted wing covers and a hard, crush-resistant chitinous body. They also have a long snout with well-developed mouthparts and a pair of antennae.
Where does the granary weevil occur and why doesn’t it live in nature?
It is a synanthropic species that occurs only in warehouses where it feeds on grain. It does not occur in nature, and its spread depends on human transport of grain.
Can granary weevils fly, and how do they spread between warehouses and homes?
No—granary weevils cannot fly because they lack membranous wings. They spread mainly through the transport of infested grain by humans.
What grains and stored products are most at risk from granary weevils?
Stored cereal grains are at risk because the granary weevil feeds on grain in warehouses. The insect’s size can vary depending on the type of grain, being smaller in grains like millet or sorghum and larger in larger grains like corn.
What should I do if I find granary weevils in stored grain?
The article indicates that granary weevils infest stored grain and spread via transported grain. If you find them, treat it as a storage infestation and check stored grain batches that may have been transported or introduced recently.
