Coffee Bean Weevil (Araecerus fasciculatus) | Post-Harvest Pest of Coffee and Dried Goods
Coffee Bean Weevil (Araecerus fasciculatus)
A Silent Threat to Coffee and Stored Agricultural Products
The Coffee Bean Weevil (Araecerus fasciculatus) is a small beetle that causes significant damage to both fresh and stored agricultural products—particularly coffee beans, dried cassava, and various dried goods such as spices, herbs, and flours. Though small, it is a persistent pest that affects product quality and market value, especially in high-value crops like coffee.
This insect is widespread in tropical and subtropical regions, particularly where high humidity and poor post-harvest management exist.
Basic Information
- Common Name: Coffee Bean Weevil
- Scientific Name:Araecerus fasciculatus (De Geer)
- Family: Anthribidae
- Order: Coleoptera
Morphological Features
- Body Size: 3.0–5.0 mm
- Color: Grayish-brown with white and dark-brown hair patterns
- Antennae: Capitate (clubbed), with enlarged tips
- Forewings: Hardened elytra
- Hindwings: Transparent membranes
- Legs: Walking legs with distinct white banding on each tarsus
- Mouthparts: Chewing type
- Eggs: Slender, white
- Larvae: Cylindrical, legless, yellow-brown
Biology & Behavior
- Naturally found on tree bark, leaves, decaying plant matter, and organic soil
- Prefers laying eggs in fermented, acidic, or dried fruit-based substrates
- Not a disease vector but a major quality-damaging pest for stored goods
Life Cycle (Complete Metamorphosis)
Egg Stage:- ~50 eggs/female
- Hatch in 3–5 days (depending on temperature and humidity)
- Develops inside coffee beans or dried plant materials
- Thrives in environments with >60% RH
- Slower development under low humidity
- Lasts 29–57 days
- Lifespan ~17 weeks
- Total life cycle: 46–66 days
Host Plants & Damage Symptoms
Affected Crops:
- Coffee beans
- Dried cassava, yam, taro
- Cocoa, ginger, ginseng, garlic
- Dried spices, wheat flour, cassava flour, millet, etc.
Damage:
- Larvae burrow and feed inside dried seeds or tubers
- Reduces internal quality, causes hollowness and weight loss
- Although not always visible, damage significantly reduces grade and market price
Geographic Distribution
- Native to India
- Now found throughout humid tropical and subtropical regions
- Common in poorly managed post-harvest storage zones, including Southeast Asia
Prevention & Control Strategies
✅ Cultural Practices:
- Harvest coffee at optimal timing
- Remove overripe or fallen coffee fruits from trees and ground
- Prune trees to allow airflow
- Avoid drying coffee cherries on bare soil or near production fields
✅ Biological Control:
- Apply Beauveria bassiana (entomopathogenic fungus) to soil or plantation floors
- Use chili powder or botanical repellents around tree bases
- Deploy bait traps to reduce adult populations
Note: This weevil often overwinters in soil and re-emerges with the next crop cycle.
✅ Conclusion
While Coffee Bean Weevils (Araecerus fasciculatus) are not known vectors of disease, they pose a serious threat to the quality of high-value dried agricultural products like coffee, cocoa, and medicinal herbs. Effective control requires an integrated approach—combining physical, cultural, and biological methods—to ensure product quality and reduce post-harvest losses sustainab-2.jpg)
Coffee Bean Weevil (Araecerus fasciculatus) — 3 High-Intent FAQs
Q: 1 Is this the coffee bean weevil or the coffee berry borer—and how can I tell fast?
A:- Coffee bean weevil (CBWv): Attacks stored products (green coffee, spices, flours). Adults are 3–5 mm, mottled brown, with clubbed (capitate) antennae. Beans show irregular, ragged holes and light frass; multiple commodities in the same room may be hit.
- Coffee berry borer (CBB): Attacks on the tree; adults are much smaller (~1.7 mm), uniformly dark; berries show a single neat pinhole near the disc and damage starts pre-harvest.
Q: 2 What’s the quickest, low-chemical way to eliminate weevils from coffee lots?
A:- Heat: Treat bagged green coffee at 60 °C for 10–15 min (core temperature) or 55 °C for ~1 hr; kills all life stages with minimal flavor impact if done carefully.
- Freezing: Hold at –18 °C (0 °F) for 72 hr (small packs can be 48 hr). Thaw sealed to avoid condensation.
- Hermetic/CO₂ purge: Store in hermetic liners (e.g., grain bags) and flush with CO₂ or allow O₂ to drop <1–3%; larvae and adults cannot survive.
- Cull & clean: Discard heavily bored beans, vacuum frass, dry-clean machinery/silos, and sieve fines that harbor larvae.
- Note: Roasting instantly kills weevils, but infested beans cup poorly (stale/earthy notes) and should be removed to protect quality.
Q: 3 How do I prevent re-infestation during storage and transit?
A:- Moisture discipline: Dry green coffee to ≤11–12% moisture and keep warehouse RH <60%; CBWv pressure spikes above this.
- Hermetic logistics: Use lined bags/liners inside jute; seal pallets with shrink + desiccants for humid routes.
- Quarantine & monitor: Isolate incoming lots 7–14 days, place flour/coffee bait jars or sticky cards as sentinels, and inspect weekly.
- Sanitation & rotation: Deep-clean floors/racks, remove over-ripe/fallen cherries around mills, enforce FIFO, and never dry on bare soil.
- Biological assist: Apply Beauveria bassiana to floors/soil margins in humid mills; it suppresses adults emerging from refugia.
Are they unsafe for people? They’re not disease vectors, but even light infestations downgrade quality and price. The best practice is prevention + rapid lot treatment rather than tolerating “insect-tainted” coffee.
