Rugose scarab

Systematic position: The rugose scarab (Dyscinetus rugifrons) belongs to the order Coleoptera and the family Scarabaeidae. It is a member of the Dynastinae subfamily, known as rhinoceros or dung beetles, which are often significant pests in tropical and subtropical agriculture due to their root-feeding habits.

Crops affected: This pest primarily targets grasses and monocotyledonous crops. Economic damage is most frequently reported in rice, maize, and sugarcane plantations. It also poses a potential threat to forage grasses and various cereal crops, particularly during the establishment phase of plant development.

Biology and life cycle: The life cycle includes egg, larval, pupal, and adult stages. Females lay eggs in moist soil enriched with organic matter, which serves as an initial food source for the developing larvae. As larvae grow, they migrate toward living plant roots. Adult beetles are primarily nocturnal and are attracted to light, which can sometimes be used for monitoring populations.

Damage and severity: The damage is largely caused by larvae feeding on root systems, leading to nutrient deprivation, water stress, and plant wilting. In severe cases, the entire root architecture is destroyed, resulting in plant death. Adult beetles may also damage germinating seeds and stem bases, causing thin stands and uneven crop distribution across the field.

Control measures: Integrated pest management (IPM) is essential for controlling Dyscinetus rugifrons. Recommended strategies include:

• Implementing crop rotation with non-host plants to reduce larval population.
• Deep tillage to physically disrupt larvae and expose them to natural predators.
• Using seed treatments with systemic insecticides to protect seedlings during the critical growth phase.
• Monitoring soil moisture and utilizing biological control agents such as entomopathogenic nematodes or fungi.