Insect
Angoumois Grain Moth
Sitotroga cerealella
Biology
The Angoumois grain moth, Sitotroga cerealella (Olivier), is a primary pest of stored grains, belonging to the family Gelechiidae. Adults are small, delicate moths with a wingspan of 10-16 mm. The forewings are yellowish-brown, often with a few indistinct dark spots, while the hindwings are gray and deeply fringed. The larval stage is the damaging instadfe, a creamy-white caterpillar with a brownish head, growing to about 5 mm. Larvae develop through 4 instars within a single grain kernel. The life cycle from egg to adult typically spans 30-40 days under optimal conditions (25-300C and 70-80% RH), but can extend significantly in cooler, drier environments.
Behaviour
Oviposition occurs on or near the host material, with females laying approximately 40-300 eggs over a period of 4-20 days. Eggs hatch in 4-8 days, and the neonate larva bores into a grain kernel, sealing the entrance hole. Development is entirely internal within the grain, making early infestations difficult to detect. Pupation occurs within the grain, and the adult moth emerges by cutting a small, circular exit hole, often leaving behind a characteristic 'window' in the seed coat. Adults are nocturnal, exhibiting positive phototaxis and are often observed flying aimlessly.
Habits
Angoumois grain moths are attracted to whole grains, including corn, wheat, rice, sorghum, and barley, both in storage and in the field prior to harvest. Infestations typically begin in the superficial layers of grain masses, but larvae can penetrate deeper. Conducive conditions for rapid population growth include high moisture content in grain (>13%) and temperatures above 200C. These moths are particularly problematic in farm-stored grain, susceptible to outdoor environmental influences. Adults do not feed, relying on energy reserves accumulated during the larval stage. Their presence in stored grain often indicates long-term storage or poor sanitation practices.
Control methods
- 1Inspect incoming grain for signs of infestation.
- 2Rotate and aerate stored grain regularly.
- 3Maintain low grain moisture content and temperature.
- 4Sanitize storage bins before adding new grain.
- 5Apply appropriate residual insecticides to storage surfaces.
- 6Implement insect monitoring traps.
Tailored to Angoumois Grain Moth
IPM Procedure Checklist
Inspection
- Inspect harborage near food, water and warmth
- Check cracks, voids and appliance interiors
- Place sticky monitors at suspected hot-spots
Identification
- Confirm Angoumois Grain Moth (Sitotroga cerealella) — not a look-alike
- Note life stage and risk level: Moderate
- Capture clear photos and samples for the record
Action Thresholds
- Trigger action when monitor counts trend up
- Re-evaluate weekly during active season
- Document trigger criteria in the IPM plan
Prevention
- Seal cracks, plumbing penetrations and wall voids
- Eliminate moisture sources and standing water
- Improve sanitation: sealed food storage, grease removal
Control Methods
- Inspect incoming grain for signs of infestation.
- Rotate and aerate stored grain regularly.
- Maintain low grain moisture content and temperature.
- Sanitize storage bins before adding new grain.
Monitoring & Evaluation
- Service monitors on schedule and trend captures
- Re-inspect for Angoumois Grain Moth activity at follow-up
- Adjust tactics based on data; report findings to client