Cadelle Beetle (Tenebroides mauritanicus) | Major Storage Pest in Grains and Seeds
Cadelle Beetle (Tenebroides mauritanicus)
A Silent Threat in Global Grain Storage Facilities
The Cadelle Beetle (Tenebroides mauritanicus) is a cosmopolitan pest in the family Trogossitidae, commonly found in grain storage facilities, agricultural warehouses, and dry crop storage areas. This beetle causes damage by direct feeding and by creating access points for secondary pests. Its high tolerance to environmental conditions makes it difficult to manage if not controlled properly.
Taxonomic Information
- Common Name: Cadelle Beetle
- Scientific Name:Tenebroides mauritanicus (Linnaeus)
- Family: Trogossitidae
- Order: Coleoptera
Morphology
- Body Length: 5.0 – 11.0 mm
- Color: Glossy black
- Antennae: Clavate (club-shaped)
- Forewings (elytra): Hardened with longitudinal grooves
- Hindwings: Membranous and transparent
- Legs: Walking type
Distinctive Features:
- Head and thorax tightly fused
- Noticeable narrowing between thorax and abdomen ("waist-like")
- Smooth pronotal margin, slightly pointed at the top
Life Cycle (Complete Metamorphosis)
Egg Stage:- Duration: 7–10 days
- Female lays up to 1,000 eggs
- Eggs are elongated and off-white
- Duration: ~43 days
- Flattened body, grayish-white
- Undergoes 3–7 molts
- Duration: ~7 days
- Pupates inside seeds or wood crevices
- Lifespan: 1–3 years
- Total life cycle: ~2 months
Host Plants & Damage Symptoms
Common Hosts:
- Grains (e.g., maize, sorghum, wheat)
- Oilseeds (e.g., palm kernel, olive, sunflower)
- Seeds from the Gramineae and Compositae families
Damage:
- Eggs laid in cracks of seeds or wooden structures
- Larvae bore into the seed’s embryo, damaging germination potential
- Final instars construct pupal chambers inside seeds
- Both larvae and adults tolerate low oxygen (e.g., sealed storage)
- Can also prey on eggs and larvae of other storage insects
Distribution
Tenebroides mauritanicus is widespread in tropical and subtropical regions and can be found year-round in poorly managed storage facilities.
Prevention & Control Measures
✅ Preventive Actions:
- Remove and discard infested products promptly
- Avoid storing grains in humid or uncontrolled environments
- Inspect for cracks in seeds and packaging—common egg-laying sites
✅ Control Methods:
- Apply targeted insecticides to high-risk areas
- Consider fumigation in warehouses with a history of infestation
- Maintain regular cleaning protocols to eliminate food and harborage sources
✅ Conclusion
The Cadelle Beetle (Tenebroides mauritanicus) poses a serious threat to grain storage due to its long lifespan, hidden egg-laying behavior, and ability to survive in oxygen-limited conditions. An effective Integrated Pest Management (IPM) approach should include sanitation, routine monitoring, structural maintenance, and targeted control to ensure stored products remain safe and marketable throughout the supply chain.-21.jpg)
Cadelle Beetle (Tenebroides mauritanicus) — 3 High-Intent FAQs
Q: 1 How do I tell cadelle beetles from other stored-grain pests (e.g., saw-toothed grain beetle, lesser grain borer)?
A:- Size & color: Cadelle adults are larger (5–11 mm), glossy black.
- “Waist”: A clear narrow constriction between thorax and abdomen (looks “wasp-waisted”).
- Head & antennae: Visible head with clubbed (clavate) antennae; pronotum edge is smooth and slightly pointed anteriorly.
- Larvae: Flattened, cream-gray, with two dark, hook-like tail prongs (urogomphi)—a dead giveaway.
- Behavioral clue: Cadelles chew grain and wood and will prey on other insects’ eggs/larvae, so you may find mixed damage (chew + predation) and frass in wooden fixtures.
Q: 2 What’s the fastest, low-disruption way to stop an active cadelle outbreak in a warehouse?
A : Follow a 48–72 hour “contain–clean–kill” playbook:
1) Quarantine & triage: Isolate suspect lots; bag-test with sieves to gauge live activity.2) Mechanical removal: Vacuum cracks, beams, and pallet voids; screen out fines where larvae hide.
3) Thermal knock-down (bagged/boxed lots):
- Heat: Bring grain core to 55–60 °C for 30–60 min (or 50 °C for ~2 h) to kill all stages.
- Cold (small packs): –18 °C (0 °F) for 72 h; thaw sealed to avoid condensation.
5) Fumigation (when warranted): Whole-room/commodity phosphine or equivalent by licensed professionals—especially for deep, mixed-stage infestations.
6) Monitor: Deploy pheromone/food-bait traps and pitfall traps immediately after treatment to verify knock-down.
Tip: Cadelles tolerate low oxygen better than many pests; hermetic storage alone can be slow—pair it with sanitation/heat or a managed gas purge.
Q: 3 How do I “cadelle-proof” a facility so they don’t come back?
A:- Design out harborage: Replace or sheath wooden bins, braces, and pallets with metal/plastic; seal wall–floor junctions and bolt holes.
- Moisture discipline: Keep grain ≤12% moisture; room RH <60%; fix leaks and condensation points.
- Sanitation SOP: Daily sweep/vacuum of spillage; weekly deep-clean under belts, around legs, inside screw housings; dispose of screenings off-site.
- Inventory flow: Strict FIFO, short dwell times, and lot segregation for any returns/claims.
- Monitoring program: 1 trap per ~100 m² (more at doors & dusty zones), check weekly; investigate if ≥2 cadelles/trap/week or any larvae appear in sievings.
- Receiving QA: Inspect incoming grain and wood packaging; refuse lots with live adults/larvae or bored kernels.
- Seasonal heat clean-out: Annual empty-bin heat cycle (≥55 °C) or certified fumigation during maintenance shutdowns.
These steps—remove harborage, control moisture, monitor relentlessly, and respond fast—are what keep cadelles from turning a one-time incident into a chronic, costly problem
