Maize billbug

Sphenophorus striatopunctatus is a member of the Curculionidae family within the order Coleoptera. This species, commonly known as a type of billbug, is recognized as a significant agricultural pest that targets maize and other related graminaceous plants in various geographic regions.

The primary host for this pest is maize (Zea mays). Infestations typically occur in field conditions where the insect attacks the base of the plant. Secondary hosts may include various wild grasses that provide refuge and food resources for adult beetles, especially when cultivated crops are not present in the field.

The life cycle involves complete metamorphosis, consisting of the egg, larval, pupal, and adult stages. Adult beetles typically overwinter in soil or plant debris. Upon emergence, they feed on young plants, and females deposit eggs in the lower stems. Larvae then tunnel through the stem, consuming the pith and causing internal structural damage.

Damage caused by this pest is characterized by row-like, symmetrical holes across the leaves, which are created by adults feeding on the tightly rolled leaves before they emerge from the whorl. Larval tunneling at the base of the plant causes wilting, stunted growth, and in severe cases, the lodging or death of the corn seedling.

Effective management requires an integrated approach. Crop rotation is highly recommended to disrupt the life cycle of the pest. Additionally, using insecticidal seed treatments can protect plants during the vulnerable early growth stages. Tillage practices that bury crop residues help reduce the overwintering population, and timely scouting is essential for deciding if rescue insecticide treatments are required.