Biology of Weevils

Weevils are small beetles belonging to the family Curculionidae, one of the largest insect families in the world. Known for their distinctive elongated snouts, weevils are common pests in stored food products and can also infest homes and commercial properties throughout Calgary. Understanding their biology helps property owners identify infestations early and prevent costly damage.

What Are Weevils?

Weevils are plant-feeding beetles that range in size from 2–10 mm long. They typically have:

• A long, curved snout (called a rostrum)
  
  

• Elbowed antennae
  
  

• Hard, brown or black bodies
  
  

• Slow but steady movement
  
  

In homes, the most common species include:

• Granary Weevils
  
  

• Rice Weevils
  
  

• Maize Weevils
  
  

• Pantry Weevils found in grains, pasta, rice, flour, and cereals
  
  

Life Cycle of a Weevil

Weevils undergo complete metamorphosis, consisting of four stages:

1. Egg Stage

• Female weevils lay eggs inside kernels of grain or in cracks of stored food packages.
  
  

• A single female can lay up to 400 eggs in her lifetime.
  
  

2. Larva Stage

• The larva is a white, grub-like worm that feeds inside the grain kernel or food source.
  
  

• This stage causes most of the damage, as larvae hollow out grains from the inside.
  
  

3. Pupa Stage

• Larvae develop into pupae within the grain kernel or tightly packed food material.
  
  

4. Adult Stage

• Adults emerge from the grain, ready to reproduce.
  
  

• Adults can live several months and continue damaging stored food products.
  
  

The full life cycle typically lasts 30–60 days, depending on temperature and humidity. Warmer conditions accelerate development.

Where Weevils Are Found

Weevils thrive in areas with food sources such as:

• Kitchen pantries
  
  

• Food storage rooms
  
  

• Grain bins
  
  

• Grocery stock rooms
  
  

• Dry storage warehouses
  
  

Inside Calgary homes, infestations often begin when an infested product is brought in from a store.

What Do Weevils Eat?

Weevils primarily feed on:

• Rice
  
  

• Flour
  
  

• Cornmeal
  
  

• Pasta
  
  

• Grain products
  
  

• Seeds and nuts
  
  

Some species also attack dried beans, pet food, bird seed, and baking supplies.

How Do Weevils Spread?

Weevils spread mainly through:

• Contaminated grocery items
  
  

• Improperly sealed food products
  
  

• Warm storage areas that accelerate reproduction
  
  

• Bulk food bins with high turnover
  
  

Once inside, weevils quickly infest multiple food packages.

Signs of a Weevil Infestation

Look for:

• Tiny brown beetles in or around pantry items
  
  

• Small holes in rice, grains, or pasta
  
  

• Powdery residue in food containers
  
  

• Movement in stored food when stirred
  
  

• Adults crawling on countertops or shelves
  
  

Are Weevils Harmful?

Weevils do not transmit diseases and are not dangerous to humans or pets.
However, they:

• Cause significant food contamination
  
  

• Spread rapidly
  
  

• Can infest entire pantries if not treated
  
  

How to Prevent Weevils

To reduce the chance of infestation:

• Store grains in airtight containers
  
  

• Freeze newly purchased grains for 48 hours to kill hidden eggs
  
  

• Clean pantry shelves regularly
  
  

• Avoid buying damaged or open food packaging
  
  

• Rotate food stock (first in, first out)
  
  

Professional Weevil Control in Calgary

If you suspect a weevil infestation in your home or business, Pest Pro Exterminator offers:

• Thorough inspection of food storage areas
  
  

• Safe removal and disposal of infested items
  
  

• Professional-grade treatments for cracks, crevices, and pantry voids
  
  

• Long-term prevention strategies to avoid future infestations
  
  

👉 Visit pestproexterminator.ca or call 1-833-579-0860 for fast, reliable weevil control in Calgary.