Rust-red Flour Beetle
Colour - Glossy reddish brown and rust like.
Body - 3.5-4 mm long, flattened, relatively hairless.
Antennae - 3 segmented antennal club.
Egg - 0.6 mm long x 0.3 mm wide. White, oval.
Colour - Initially white and later turning darker and brown in the final stage.
Body - 5 mm long at maturity.
Pupa - About 3 mm long. Initially white and gradually turning brown.
Eggs are normally laid singly in flour, grain dust or occasionally on bags and wooden walls. They are covered with a sticky mucous which collects flour and dust and hardens, making them difficult to see. The females lay 1-2 eggs per day and live for about a year producing 300-600 eggs. The eggs hatch 1-2 weeks later depending on temperature and the larvae start feeding immediately on flour and broken grain. The larva can reach maximum size in 3-4 weeks and pupate. Adults emerge from the pupa 10-14 days later. In summer it can complete its life cycle in 50-60 days.
Habitats:Granaries, flour mills, processing plants and food storage areas.
Origin and History:Distribution:
Significance:Whole grain is rarely attacked, but it appears quickly after damage by other insects or milling.
It mainly occurs on grain products such as flour, meals, bran, crackers, and oil cake. It has also been found on other dried plant products, dried fruit, dried tobacco, cotton seed, animal matter and dead insects.
Its main effect is a reduction in quality of flour due to contamination and decreased gluten content, which reduces elasticity making it impossible to kneed dough from heavily infested flour.
Management and Control:Temperatures above 500C are lethal to all stages of the insect, so heating products provides effective control.
Fumigation is also used.
Related Species:Confused Flour Beetle (Tribolium confusum).
Similar Species:Granary Weevil (Sitophilus granarius)
Lesser Grain Borer (Rhyzopertha dominica)
Rice Weevil (Sitophilus oryzae)
Sawtoothed Grain Beetle (Oryzaephilus surinamensis)
References:CSIRO. The Insects of Australia. Melbourne University Press. (1991)
WADA. Insects and Allied Pests of Extensive Farming. Department of Agriculture - Western Australia Bulletin No. 4185.
Avidov, Z. and Harpaz, I. (1969) Plant Pest of Israel. Israel University Press. P260.
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