Rice weevil

Definition

A small, cosmopolitan beetle (family Curculionidae) that is among the most destructive pests of stored cereal grains and seeds, attacking intact kernels through larval feeding inside the grain. Adults are reddish-brown to blackish, 2–3 mm long, with a long, slender rostrum and four pale orange to reddish spots on the elytra; they are capable of flight and can infest standing crops before harvest, unlike some related storage pests. The species is parthenogenetic in some populations and can complete development at temperatures above 15 °C, making it a persistent threat in warm storage facilities worldwide.

Etymology

From 'rice' (principal host crop) + 'weevil' (any beetle of family Curculionidae, from Old English wifel, beetle)

Example

In grain storage facilities, rice weevil populations can build rapidly when temperature and moisture conditions permit: a single infested kernel may contain a larva that consumes the endosperm before pupating, with adults emerging through a neat, round exit hole that distinguishes Sitophilus damage from that of less specialized secondary pests.

Synonyms

• Sitophilus oryzae

Related Terms

• Granary weevil
• Maize weevil
• Stored-product entomology
• Primary pest
• Curculionidae
• Sitophilus
• Integrated Pest Management
• Phosphine fumigation

Usage Notes

Often distinguished from the flightless granary weevil (Sitophilus granarius) by its ability to fly and its slightly smaller, more slender build; maize weevil (Sitophilus zeamais) is morphologically similar and sometimes treated as a sibling species or subspecies depending on taxonomic authority. The common name 'rice weevil' is sometimes applied loosely to any Sitophilus species in agricultural contexts, though specialists reserve it for S. oryzae.