Variegated click beetle

Systematic position: The variegated click beetle (Lacon variolus) belongs to the order Coleoptera and the family Elateridae. This beetle species is widely recognized in agricultural research due to the larval stage, commonly referred to as a wireworm, which is a notorious pest of subterranean plant parts.

Affected crops: This insect is a polyphagous pest capable of damaging a diverse range of crops. It particularly impacts cereal crops, various vegetables such as potatoes and root crops, and nursery stock. The larvae show little preference and will feed on almost any plant material available within the soil profile.

Biology and life cycle: The lifecycle of Lacon variolus is characterized by a prolonged development period in the soil, which can take several years. Adults emerge in spring to lay eggs near the base of host plants. The larvae undergo several molting stages, spending years in the soil while exhibiting complex vertical migration patterns based on environmental soil conditions.

Damage and economic significance: The economic impact is primarily driven by larval feeding. Wireworms consume germinating seeds, roots, and underground stems. This damage leads to reduced plant vigor, stunted growth, and death of young seedlings, causing significant gaps in stands. Furthermore, their feeding wounds provide entry points for soil-borne fungal pathogens, increasing total crop loss.

Control measures: Management of this pest requires an integrated pest management (IPM) approach to minimize damage:

• Implementing crop rotation to disrupt the larvae's life cycle.
• Conducting deep fall tillage to expose larvae to birds and extreme temperatures.
• Using seed treatments with systemic insecticides to protect germinating crops.
• Monitoring soil populations before planting to determine the necessity of soil-applied granular insecticides.