Trigoniulids
Systematic position: Trigoniulidae is a family within the class Diplopoda (millipedes), order Spirobolida. While many millipedes act as decomposers, certain species within this family can cause significant agricultural damage when they shift to feeding on the tissues of living plants.
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Trigoniulids
Host crops: Trigoniulids are polyphagous and known to affect various agricultural crops. They are particularly destructive to vegetable seedlings, tubers, and root vegetables such as potatoes, carrots, and sugar beets. They also frequently inhabit nursery beds where irrigation levels are high.
Biology and life cycle: The life cycle of Trigoniulidae is subterranean and highly dependent on soil moisture and organic content. Eggs are laid in clusters within the soil. The larvae undergo several molts as they develop. Populations tend to explode in environments where agricultural residues are not properly cleared, providing a continuous food source and moisture.
Nature of damage: The damage is characterized by ragged, deep holes or irregular excavations on roots, tubers, and the lower stems of seedlings. These injuries not only physically damage the plant but also serve as entry points for soil-borne pathogens, leading to secondary fungal or bacterial rots that can devastate the harvest.
Control measures: Effective management relies on a combination of cultural and chemical strategies:
- Deep plowing in the autumn to expose the millipedes to predators and desiccation.
- Improved soil drainage to reduce the humidity levels favored by the pests.
- Removal of debris and weeds to eliminate potential shelter and food sources.
- Application of granular or systemic soil insecticides if the population threshold is exceeded.