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Dorsal habitus

Lateral habitus

Introduction

The broad-nosed granary weevil, Caulophilus oryzae (Gyllenhal) is a Central American species. The pest is most often encountered in tropical subsistence agriculture. The pest is often considered a minor pest of corn and stored products. It has been reported infesting avocadoes in the southern United States where it feeds on the seeds of fallen avocadoes.

Distribution

Southern United States, California, Hawaii, Cuba, Jamaica, Puerto Rico, and Central America, Europe, Madeira.

Hosts

Mainly storegrains but also attacks avocado seeds.

Damage

Both the adult and larva feeds on the kernel. The female lays eggs in grain kernels. The larva feeds and develops inside the kernel. Larva after feeding leaves a huge cavity in the kernel. The emerging adult leaves a ragged exit hole in the kernel.

Biological and Ecological Notes

Each female lays 200-300 eggs. In summer, the period from egg to adult is about a month, and the adults may live for another 5 months (Cotton, 1963), it can live longer in cooler temperatures. It chews a small hole and then inserts one egg into the hole and plugs the hole with a waxy secretion. The larva is white, grub-like and legless. It develops inside the grain kernel. It pupates inside the kernel. When the adult emerges, it chews its way out of the kernel, leaving a ragged exit hole. The development time is approximately one month under optimal conditions.

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Bibliography

Cotton, R.T. 1963. Pests of stored grain and grain products. Burgess, Minneapolis.