Sitophilus oryzae
- Insect with chitinous carapace
- Flying, crawling
- Stock/storage pest
Rice weevils live outdoors in the tropics, where they attack rice grains directly in the field to lay eggs. In this way, they eventually enter the stores in the egg/larvae stage and can destroy the entire crop there.
Rice weevils are not disease vectors.
More data
Class: Insects
Size: 2 to 3mm
Weight: Variable
Age: Unknown
Appearance: Brown-red coloured
Food: Rice, cereals
Distribution: Worldwide
Original location: Asia
Habitat: Rice and cereal stocks
Natural enemies: Parasitoid Hymenoptera
Threatened with extinction: No
- The rice weevil has a slender cylindrical shape, is brown-red, with a reddish spot on each elytra behind the shoulders and in front of the tips. There are also coarse dot stripes on the elytra, with narrow spaces between them, in which there is a row of short and erect bristles.
- Rice weevils live outdoors in the tropics and infest rice and/or grain in the field. In Central Europe, however, they can only survive in heated buildings. They appear in various stores and provisions, but can also be carried into the household.
- Females lay 100 to 200 eggs on one grain each. Besides rice, maize and wheat are also infested. They like to breed at medium to high temperatures, from about 15°C, but the preferred temperature is about 27°C. They are very drought tolerant, but reproduce much faster in humid environments. Only below 35% humidity can they not develop at all.
- To lay eggs, the beetles drill a hole in a grain with their mouthparts and lay an egg in it. They then close the hole again with a secretion. After laying, the eggs develop into larvae in the grain. These pupate and after a total of 20 to 100 days, depending on the ambient temperature, the finished beetle emerges from the hollowed-out grain. An adult beetle can survive for months without food.
- As a primary pest, adult rice weevils can infest healthy and intact cereal grains. They often also pave the way for secondary pests that like to attack damaged grain. A characteristic feature of rice weevil infestation is that the grains are hollowed out by the feeding. In case of high infestation density, the grain therefore loses weight. If the infestation is severe, the temperature of the stored goods increases due to the metabolic processes and fungi and bacteria also settle. The stored goods become lumpy, inedible and smell unpleasant. Due to the formation of condensation, the stored grains begin to grow on the surface.
In which area does the pest occur?
The area of application determines which products are recommended to control this pest.
Oben
