Sunflower Seeds & Bugs

Sunflower Seed Maggot

• Sunflower seed maggots, or Neotephritis finalis, cause sterility of sunflower seeds when newly hatched maggots burrow into sunflower blooms. The adults are flies with yellowish-brown striped wings. Adults emerge during July, with the first generation pupating in the sunflower head and the second generation overwintering in the soil. According to the University of Minnesota, a single larvae can destroy 12 ovaries, with mature maggots feeding directly on the seeds.

Sunflower Moth

• The sunflower moth, or Homoeosoma electellum, is a widespread pest in North America, and also occurs in Mexico and the Canadian prairie provinces. Adult sunflower moths are shiny gray, and the larvae have alternate dark and light stripes over a tan body. Sunflower moths lay eggs at the base of the sunflower florets and then develop into young instars that feed on the florets. As the instars mature, they bore into the sunflower head and consume the seeds and receptacle tissue, leaving sunflowers susceptible to further tissue damage from fungal infection.

Tarnished Plant Bug

• The tarnished plant bug, or Lygus lineolaris, damages sunflower seeds by feeding on the reproductive organs or the leaf tissue, killing the surrounding tissues and thereby causing bitter-tasting seeds with brown spots. Adults are often confused with aphids and are pale green to dark brown with a triangle of yellow on the wings. Adults overwinter in leaf litter, producing two generations per year. All stages of tarnished plant bugs have been noted in all stages of the sunflower's reproductive growth.

Red Sunflower Seed Weevil

• The red sunflower seed weevil, or Smicronyx fulvus, occurs from the Appalachian Mountains to the Pacific Northwest. They cause reduced sunflower seed weight and oil content when the larvae feed on seeds. The adults feed on the sunflower bracts, damaging them by creating pinpoint holes in the tissue. Adults are 2.5 to 3 mm long with reddish-orange scales. Females lay eggs in the pericarp of the sunflower seed. When the larvae are mature, they cut a hole in the seed, dropping to the ground and overwintering in the soil and emerging in early June as pupae.