Polydesmus coriaceus

Polydesmus coriaceus is a species of flat-backed millipede belonging to the order Polydesmida and the family Polydesmidae. These organisms are typically found in moist environments rich in organic matter. While they are primarily decomposers in natural ecosystems, they frequently become problematic pests in agricultural settings, particularly in nurseries, greenhouses, and vegetable fields.

This pest targets a wide variety of crops, demonstrating a particular preference for succulent plant parts. Major damage is observed in root crops like potatoes, carrots, and sugar beets. Furthermore, Polydesmus coriaceus often attacks the tender stems and root systems of young seedlings, which can lead to significant crop loss and reduced yields early in the growing season.

The biology of the species is characterized by a strong dependence on high soil moisture levels. Females lay eggs in small underground chambers protected by secretions. The larvae undergo several molts, gradually increasing their body segments as they grow. Due to their extended life cycle, populations can remain established in the soil for several years if environmental conditions remain favorable.

Damage caused by these millipedes is characterized by irregular pits and cavities on the surface of root vegetables. These feeding sites are not only damaging in themselves but also create entry points for soil-borne pathogens, such as fungi and bacteria, which cause further decay. During wet seasons, population densities can surge, leading to widespread infestation in commercial crop production.

Managing Polydesmus coriaceus requires a combination of good agricultural practices and chemical control when necessary. Improving soil drainage, removing decomposing organic matter, and practicing proper crop rotation are essential non-chemical steps to reduce habitat suitability. In professional agriculture, the use of registered soil insecticides, when applied according to the label, can effectively suppress severe infestations.

• Ensure proper soil drainage to limit moisture.
• Remove plant debris to reduce food sources.
• Maintain a diverse crop rotation cycle.
• Apply lime to acidic soils to make the environment less favorable.
• Use certified soil treatments if infestation levels are high.