Flat-backed millipede

The flat-backed millipede (Polydesmus monilaris) belongs to the class Diplopoda, the order Polydesmida, and the family Polydesmidae. It is a soil-dwelling arthropod that, under conditions of high humidity, can transition from a soil decomposer to a significant agricultural pest.

This pest primarily targets crops with succulent roots or those growing in organic-rich, moist soils. It is frequently observed attacking root vegetables, including carrots, beets, and potatoes, as well as seedlings, causing significant losses in greenhouse nurseries and outdoor vegetable production.

The biological development of this millipede is heavily dependent on microclimate conditions. They are most active in dark, damp environments and complete their life cycle in the upper soil layers. They feed by rasping and biting through plant tissues, using their mouthparts to penetrate the soft outer layers of roots and stems.

The damage caused by Polydesmus monilaris is characterized by deep, irregular pits and tunnels in root structures. These wounds not only stunt the plant growth but also serve as entry points for pathogens, leading to secondary rot diseases that can destroy a crop before it is even harvested.

Effective management requires a combination of cultural practices and targeted control. Because they thrive in wet, undisturbed soil, modifying the environment is key to suppression. Recommended practices include:

• Implementing proper soil drainage to reduce overall moisture levels.
• Practicing regular cultivation to disturb their habitat and expose them to natural predators.
• Removing organic debris and crop residues that provide shelter and food.
• Applying soil-based insecticides only when necessary and as directed by agricultural standards.