Greater Wax Moth
Galleria mellonella (Linnaeus)
📖 Description
Greater Wax Moth (Galleria mellonella) is one of the most serious pests of managed honey bee colonies and stored beeswax comb across the Indian subcontinent and worldwide. Particularly severe in apiaries of Apis cerana indica (Indian hive bee — native, kept in traditional log and frame hives throughout India) and Apis mellifera (European honey bee — widely used in commercial Indian apiaries for honey production and pollination rental). India produces over 95,000 tonnes of honey annually (worth over ₹1,800 crore per year), with major beekeeping belts in Punjab, Haryana, Uttar Pradesh, Bihar, West Bengal, Maharashtra, Tamil Nadu, Kerala, Karnataka, and the Northeast. The pest is unusual among apicultural pests because (a) only the larval stage damages comb — adults do not feed on wax and live only 7-15 days, (b) larvae can digest and metabolise beeswax (a complex lipid that very few insects can use as food) due to their gut symbionts, including bacteria that break down wax esters, (c) a single female lays 300-600 eggs in crevices of hive wood or comb, with larvae developing over 6-7 weeks and reaching 20-28 mm length before pupating in tough silken cocoons attached to hive wood, (d) the pest is most damaging to stored comb (supers kept between seasons) and to weak or queenless colonies that cannot defend themselves, (e) populations build up rapidly in the warm humid months of monsoon and post-monsoon (Jun-Nov) — exactly when bee colonies may be weakened by dearth and when stored comb is most vulnerable, and (f) the pest has been used as a model organism in insect physiology and immunology research worldwide, with laboratory colonies maintained in many institutions. IPM with strong colony maintenance (most effective), regular hive inspection, prompt removal and freezing of infested comb, Bt and acetic acid treatments for stored comb, PDB fumigation for long-term comb storage, screened bottom boards, full-sun apiary placement, and good apiary hygiene provides effective and sustainable control. The pest is a particular concern for Indian beekeepers because (i) India is a major honey-producing nation with over 12 lakh bee colonies and rapidly growing commercial apiculture, (ii) much Indian beekeeping is done by small and marginal farmers with limited access to IPM knowledge and equipment, (iii) India’s warm humid climate favours wax moth development year-round in many regions, (iv) traditional log and clay hives (still widely used for Apis cerana in many parts) provide numerous crevices for moth egg-laying, and (v) migratory beekeeping (where colonies are moved between crops) can spread wax moth between apiaries.
⚠️ Symptoms to watch for
- Silken tunnels and galleries in brood comb and honey comb, webbing and frass accumulation in comb cells, damaged wax foundation and queen cells, 'comb-meltdown' in severe infestations where larvae web together large areas of comb with silk and frass, absconding of bee colony due to disturbance, loss of stored honey and pollen, contamination of honey with silk and larval frass (makes honey unfit for sale), weakened bee colonies (reduced brood rearing and honey storage), complete destruction of stored drawn comb in unattended apiaries. Economic loss 30-60% of comb in neglected apiaries; complete loss of stored comb in unused supers.
🩹 Treatment
- Inspect hives every 7-10 days during active season and remove infested combs, freeze infested comb at -7°C for 4.5 hours or -15°C for 2 hours (kills all stages), use narrow bottom-board entrances (reduces moth entry), keep colonies strong and populous (bees themselves defend against wax moth — weak colonies are most vulnerable), do not store drawn comb supers without protection (use PDB crystals/para-dichlorobenzene fumigation or stack with mothballs)
🌿 Organic treatments
- Maintain strong populous colonies (the most effective biological control — worker bees kill and remove wax moth eggs and larvae), use Bt (Bacillus thuringiensis var. aizawai) spray on stored comb (targets caterpillar gut — safe to bees when applied to stored comb only), apply entomopathogenic fungus Beauveria bassiana to stored comb, fumigate stored comb with acetic acid (glacial acetic acid — kills all stages, leaves no residues, must air out before use), use essential oil blends (peppermint, lemongrass, thyme oil) on stored comb (repels adult moths), expose stored comb to bright sunlight in sealed clear plastic bags (heat kills larvae), use upper ventilation to prevent humidity buildup (which favours wax moth), keep hives in full sun (reduces moth activity), use screened bottom boards with vegetable oil tray (traps falling wax moth larvae)
🧪 Chemical treatments
- PDB (para-dichlorobenzene) crystals @ 6-8 crystals per shallow super for stored comb fumigation (most common commercial treatment — comb must be aired 24 hours before use to prevent bee mortality), aluminium phosphide (Phostoxin) tablets @ 1 tablet per 5 stacked supers in sealed stacks (extremely effective — use only by trained operators, lethal to humans if mishandled), sulphur fumigation @ 50 g sulphur per cubic metre of stacked comb (controls wax moth, leaves sulphur smell — air well before use), ethylene dibromide (largely discontinued — restricted use). NEVER apply chemical insecticides inside active bee colonies — they kill bees.
🛡️ Prevention
- Maintain strong populous bee colonies (the single most effective wax moth prevention — worker bees kill and remove wax moth eggs and larvae), never leave drawn comb unattended in unused supers, store drawn comb in sealed stacks with PDB crystals or after Bt/acetic acid treatment, inspect hives every 7-10 days during active season, replace old dark comb with new foundation (old comb is more attractive to wax moth), keep hives in full sun (reduces moth activity), use screened bottom boards with oil tray (traps falling larvae before they pupate), reduce entrance size during dearth periods (restricts moth entry), avoid splits/nucleus colonies too small to defend their comb, store harvested honey supers promptly after extraction and never leave them in the apiary, manage Indian hive beetle and small hive beetle (which create conditions favourable for wax moth), use queen excluders to keep brood nest compact (reduces undefended comb), practice good apiary hygiene (clean dead hives, burn heavily infested comb).
🪴 Affected plants
- Honey bee colonies (Apis cerana indica, Apis mellifera, Apis dorsata, Apis florea); damages beeswax combs, stored wax foundation, beeswax sheets; also feeds on bee bread, pollen, and honey. Not a plant pest — an apicultural pest of managed and wild honey bee colonies.
🦋 Natural predators
- Worker bees (most important — kill and remove eggs and larvae in strong colonies), ants (capture wandering larvae), pirate bugs (Orius spp. — feed on eggs), spiders (capture adult moths), earwigs, silverfish (limited), predatory bugs. No commercial biological control agents are widely used.
🌱 Host plants
- Honey bee colonies (Apis cerana, Apis mellifera, Apis dorsata, Apis florea) and stored beeswax comb. Not a plant pest.
🔄 Lifecycle
- Adult female lays 300-600 eggs in crevices of hive wood or comb.
- Egg incubation 5-8 days.
- Larva passes through 8-10 instars over 28-50 days (depending on temperature and food quality); larvae tunnel through comb, leaving silken galleries.
- Mature larva pupates in a tough silken cocoon attached to hive wood.
- Pupal stage 14-21 days.
- Adult lifespan 7-15 days (does not feed).
- Total life cycle 6-12 weeks at 25-30°C; 4-6 overlapping generations per year in tropical India.
- Larvae can survive 5+ months of cold or starvation by entering diapause.
📅 Season
- Year-round in tropical India; peaks Jun-Nov (warm humid monsoon and post-monsoon conditions most favourable for moth reproduction, and bee colonies may be weakened by dearth during this period)
🔎 Appearance
- Adult is a medium-sized, grey-brown moth with narrow wings; forewings grey with dark mottling, hindwings pale grey with a long fringed margin.
- At rest, wings are folded tent-like over the body.
- Larvae are creamy-white caterpillars with a brown head capsule, dark brown pronotal shield, and sparse bristles; body tapering at both ends.
- Pupae are brown, inside tough silken cocoons attached to hive wood.
- Larvae are the damaging stage — they tunnel through beeswax comb, leaving silken galleries filled with frass.
💥 Damage level
- Moderate
🔁 Reproduction rate
- Fast
🗺️ Geographic regions
- Indian Subcontinent
- South Asia
- Southeast Asia
- Cosmopolitan in Tropical
- Subtropical
- and Temperate Regions Worldwide
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