The Rice weevil, Sitophilus oryzae damages rice (main), maize and other cereals in storage (alternative).
Damage: The developing larva lives and feeds inside the grain hollowing it out in the process. In rice (the preferred host) the entire grain is usually destroyed by the time the adult emerges. Pest status: A very serious major (primary) pest of stored rice and other cereals in the warmer parts of the world.
Life history: Identical to S. zeamais so far as is known, but preferably taking place in rice. Eggs are white and oval. The female lays the eggs inside the grain by chewing a minute hole in which each egg is deposited, followed by the sealing of the hole with a secretion. These eggs hatch into tiny grubs which stay and feed inside the grain and are responsible for most of the damage. Mature larvae are plump, legless and white, about 4 mm long. Pupation takes place inside the grain. The adult beetle emerges by biting a circular hole through outer layers of the grain. They are small brown weevils, virtually indistinguishable from each other, about 3.5-4.0 mm long with rostrum and thorax large and conspicuous. The elytra are uniformly dark brown. Each female is capable of laying 300-400 eggs, and the adults live for five to eight months and are capable fliers. The life-cycle is about five weeks at 30oC and 70% RH; optimum conditions for development are 27-31oC and more than 60% RH; below 17oC development ceases.
Distribution: The two species, Sitophilus oryzae and S. zeamais, are virtually cosmopolitan throughout the warmer parts of the world. In Europe they are replaced by the temperate Palaearctic species S. granarius which is distinguished by the punctate sculpturing on the prothorax and elytra, and by the fact that it is wingless and hence cannot fly.
An attempt to reconstruct the natural and cultural history of the granary weevil, Sitophilus granarius (Coleoptera: Curculionidae)
Jan 01, 2010; Key words. Curculionidae, Sitophilus, evolution, phylogeny, adaptation, archaeology, history Abstract. It is generally...
Responses of Sitophilus oryzae (Coleoptera: Curculionidae) and Tribolium confusum (Coleoptera: Tenebrionidae) to traps baited with pheromones and food volatiles
Jan 01, 2006; Key words. Pheromone, food volatiles, traps, stored-product beetles, Sitophilus oryzae, Tribolium confusum Abstract. The...