Sugarcane beetle

Systematic position: Ligyrus cuniculus is a member of the order Coleoptera, family Scarabaeidae, and subfamily Dynastinae. This beetle is recognized as a significant agricultural pest, specifically impacting sugar production in tropical and subtropical regions where it thrives in moist, organic-rich soil.

Host plants: The primary host of the sugarcane beetle is sugarcane (Saccharum officinarum). However, the larvae are known to be polyphagous and can infest the root systems of corn, rice, and various grasses, particularly when these crops are planted in fields recently cleared of sugarcane or those with high organic content.

Biology and life cycle: The insect undergoes a complete metamorphosis. Adult beetles are primarily nocturnal and are strongly attracted to light sources. Females deposit eggs in the soil, and the resulting larvae pass through three larval instars, feeding voraciously on plant roots before pupating within the soil profile.

Damage and economic impact: Damage is primarily caused by the larval stage. By feeding on the roots and the base of the shoots, the larvae disrupt nutrient and water uptake. Infested plants exhibit stunted growth, yellowing, and eventually lodging or death. In severe cases, the entire stand of sugarcane can be thinned, leading to substantial yield losses.

• Deep tillage to expose larvae to natural predators.
• Crop rotation to break the pest's life cycle.
• Application of entomopathogenic fungi or nematodes.
• Soil-applied insecticide treatment at planting.
• Monitoring adult populations with light traps.

Management practices: Effective management of Ligyrus cuniculus requires an integrated approach. Cultural practices such as maintaining field hygiene and removing crop debris are essential to reduce the population density. When cultural methods are insufficient, chemical control using soil-applied granular insecticides is implemented to protect the root zone during the critical early growth stages.