Lepidiota negatoria

Lepidiota negatoria is a species of beetle belonging to the family Scarabaeidae within the order Coleoptera. Recognized as a significant soil-dwelling pest, it has adapted to feed on the root systems of various crops, posing a continuous threat to agricultural stability in its native and invaded geographical ranges.

The primary economic host for this pest is sugarcane. The larvae live underground for extended periods, feeding aggressively on the roots, which directly inhibits the plant's ability to absorb water and nutrients. This damage leads to stunted growth, reduced stalk quality, and in severe infestation scenarios, the complete death of the sugarcane stool.

The lifecycle of this beetle follows a complete metamorphosis consisting of the egg, larval, pupal, and adult stages. The adult beetles typically emerge from the soil during the rainy season to mate and lay eggs. The larval stage, which involves several instars, is the most destructive phase, as the larvae remain active in the rhizosphere, consuming root biomass and causing extensive underground destruction.

Damage assessment often relies on identifying chlorotic leaves and irregular patches of withered plants in the field. When uprooted, affected plants show truncated or severely eaten roots. The resulting economic loss is cumulative, as damage in one season can affect the ratoon crop growth in subsequent years, leading to lower sugar recovery rates.

Integrated Pest Management (IPM) is essential for controlling Lepidiota negatoria. Strategies include:

• Application of granular insecticides at the time of planting to protect the root zone.
• Monitoring adult flights using light traps to predict larval population density.
• Biological control using specialized pathogenic fungi or bacteria that target scarab larvae.
• Cultural practices like deep soil tillage to expose larvae to sunlight and natural predators.