Phyllophaga cuyabana

Systematic position. Phyllophaga cuyabana is a member of the order Coleoptera and the family Scarabaeidae. These beetles, often referred to as May beetles or June bugs, are among the most significant soil-dwelling pests affecting agriculture in South American regions.

Crops affected. This pest primarily targets large-scale commodity crops, with soybeans, corn, sorghum, and wheat being the most susceptible. The damage is cumulative as the larvae remain active in the rhizosphere, focusing on the root systems of developing seedlings.

Biology and life cycle. The life cycle of Phyllophaga cuyabana typically follows a one-year pattern. Adult beetles emerge to mate, and females lay eggs in the soil. Upon hatching, the larvae undergo three larval instars, feeding voraciously on roots and organic matter, which allows them to reach maturity before the next generation cycle.

Damage character and economic importance. The larvae, commonly known as white grubs, prune the roots of young plants. This physiological disruption leads to stunted growth, wilting, and decreased nutrient uptake, ultimately resulting in reduced crop stands and significant yield losses if infestations reach economic thresholds.

Protection measures. Managing this pest requires an integrated pest management (IPM) approach:

• Pre-planting soil sampling to determine larval population density.
• Use of systemic insecticidal seed treatments to protect roots.
• Implementation of crop rotation to break the pest's life cycle.
• Application of soil-applied granular insecticides during the planting operation.
• Mechanical soil disturbance to expose larvae to natural predators.