Sunflower stem weevil

The sunflower stem weevil (Cylindrocopturus adspersus) is a coleopteran pest belonging to the Curculionidae family. It is recognized as a significant threat to sunflower production, primarily causing economic losses by compromising the structural integrity of the crop stems.

Both adults and larvae contribute to the damage caused to the sunflower plants. While adults feed on the leaves and epidermis of the stems, the larvae cause the most significant internal damage by tunneling into the pith, which interferes with nutrient and water transport within the plant.

The biological cycle of this pest involves the emergence of adults in early summer. Females lay their eggs in the lower parts of the stem, and the developing larvae remain inside the plant throughout the growing season. They overwinter as larvae, primarily within the lower stubble or roots of the sunflower plants.

The impact of this pest includes lodging, reduced head diameter, and lower seed weight. Heavy infestations can lead to substantial yield losses, especially in regions with high winds, as the internal tunneling weakens the stem, making it prone to breaking before harvest.

• Tillage practices that bury sunflower residues to disrupt the overwintering population.
• Crop rotation to reduce the buildup of pest populations in local fields.
• Monitoring the activity of adults during the early developmental stages of the crop.
• Timely application of chemical control agents if threshold levels are exceeded.
• Selecting robust sunflower hybrids with higher tolerance to physical stress.