Weevils

Features

Weevils are pests of stored grain and seeds. They develop inside whole grain kernels as small, white, wrinkled, grub-like larvae. Adult weevils are approx. 10mm long with a ‘moth-like’ appearance. They are brown to reddish brown in colour.

Life Cycles

The larvae will eat and grow inside the seed, becoming visible until after about one month when the adult weevil chews through the seed coat and emerges.

Habits

Weevils are commonly found inside the pantry cupboards where food is stored. The infestation may originate from food seeds or beans in the cupboards, garden seeds, popcorn, cereals, corn, maize wheat, barley, rice, etc.

Infestation may occur when larvae are present in items purchased from the store, or when access is gained into the cupboard by an adult weevil. This leads to further infestation, spreading to other food products. Adults can chew through plastic and paper wrappers and decimate stock on shelves or in stores at homes, shops and warehouses.

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Type	Features	Feeding Habits	General Comments	Photo
Small Brown Ants
Granary & Rice Weevils	Adults are dark brown, distinguishable from borers & beetles by their long snout. The rice weevil has reddish spots on its body. 2.0-3.5mm in size.	Grain	Females produce 200-300 eggs in their 2-3 month life span. These are deposited in whole kernels of grain; emerging larvae feed on whole grain. Adults can’t fly and feign death if disturbed.
Indian Meal Moth	Outer part of the forewing is reddish-brown and inner part is creamy-white. Adults have a wingspan of 20 mm.	Oilseeds and cereals	Attacks oilseeds and cereals. Eggs are laid on the surface of the grain. Larvae spin webs on the surface of the grain and consume kernels within the webbing.
Lesser Grain Borer	Adults are dark brown and can fly. 2.0-3.5mm in size.	Grain	Females produce 200 - 400 eggs in their 2-3 month life span. Eggs are laid on the surface of the grain and larvae burrow into the kernels.
Rust-Red Flour Beetle	Adults are reddish-brown. 2.3-4.4 mm in size.	Grain and oilseeds	Females produce from 10-20 eggs per day in their 200 day life span. Capable of infesting both whole grain and oilseeds, but a more serious problem in stock feed & processed grain (i.e. flour).
Saw-toothed Grain Beetle	Adults are brown with tooth-like projections on either side of the thorax. 2.5-3.5 mm in size.		Adults may live for several years and females produce an average of 375 eggs.
Tropical Warehouse Moth	Adults are grey with a dark band across the middle of the forewing. Adults have a wingspan of 15 mm.	Cereal grain and oilseeds	Attacks cereal grain and oilseeds. Females may lay up to 250 eggs on the surface of the grain in their 2 week life span. Larvae spin webs on the grain surface and consume kernels within the webbing.