| Description |
These insects are often grouped together as the ‘flat grain beetles’. Technically they are the rusty grain beetle, Cryptolestes ferrugineus, the flat grain beetle, Cryptolestes pusillus, and the flour mill beetle, Cryptolestes turcicus. Adults are small (1.5–2.0 mm), reddish brown, shiny and flattened with long bead-like antennae. Adults have a ridge (sublateral carina) on the head and prothorax. Larvae are elongate and flattened with well-developed legs. Larvae are pale, white to yellow in colour with a darkened head capsule and dark urogomphi present. |
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| Similar species |
Rusty grain beetle (Cryptolestes ferrugineus) Flour grain beetle (Cryptolestes turcicus) Foreign grain bettle (Ahasverus advena) |
| Pest status | Is distributed worldwide, but is more common in wet-tropical and warm-temperate regions. |
| Risk period | All year round. |
| Commodities affected | Mainly damages grain, preferably wheat, but will also feed on beans, bulbs, maize, malt barley, rice, sorghum. |
| Signs of infestation | Damage is not readily identifiable as being caused by this species. |
| Damage |
Damage is usually restricted to grain stored under high moisture conditions. Both larvae and adults feed on germ and endosperm. Heavy infestations may cause grain to heat and spoil. Damage may spread fungal spores through grain. |
| Life cycle | Females lay eggs in crevices or loosely amongst the food. Larvae move actively amongst the food feeding on the endosperm or germ. Development from egg to adult of the flat grain beetles taking 22–24 days at 32–35°C and 75% r.h. |
| Means of protection |
Cultural control – The insect does not occur in standing crops. Therefore, good hygiene with storage and handling equipment should minimise infection. Prevention treatment by Methograin Delta IGR Grain Protectant is the primarily recommended product for prevention. To gain the widest possible range of protection Methograin Delta IGR Grain Protectant together with Methograin Fenitrothion 1000 can be applied. Chemical control – In case of infestation, fumigation in sealed storage. |
