Square-necked grain beetle

The square-necked grain beetle (Cathartus quadricollis) is a notorious stored-product pest within the order Coleoptera and the family Silvanidae. Primarily found in tropical and subtropical climates, this insect has become a global concern due to international grain trade, frequently infesting elevators, warehouses, and processing facilities where food products are stored.

This beetle is known to infest a wide variety of stored food commodities. Its preferred diet includes maize, wheat, rice, flour, bran, and oilseeds. Furthermore, it often feeds on dried fruits, nuts, and processed plant materials, making it a versatile and persistent threat to the integrity of agricultural inventory held in long-term storage.

The biological cycle of this pest is characterized by high reproductive potential. Adults are small, flattened beetles that are capable of flight, allowing them to disperse quickly within storage facilities. Eggs are deposited on the surface of the food source. Larvae feed primarily on the broken kernels or flour dust, eventually pupating within or near the food substrate, which allows populations to explode in poorly managed grain bulks.

The economic impact of Cathartus quadricollis is significant due to both qualitative and quantitative losses. By feeding on the germ of the grain, they reduce the seed viability and nutritional quality. Their activity creates favorable conditions for mold growth and mycotoxin development by causing grain heating, which can compromise the quality of the entire stockpile and lead to substantial commercial losses.

Effective management strategies require a combination of preventative sanitation and chemical interventions:

• Maintaining rigorous sanitation protocols in warehouses to eliminate food residues.
• Drying grains to moisture levels below the threshold suitable for larval development.
• Regular inspection and monitoring of grain bulk temperatures to detect early stages of infestation.
• Applying authorized structural treatments and residual insecticides in storage areas.
• Using fumigation as an emergency measure for heavily infested grain stocks to ensure pest eradication.