Bluegrass Billbug – Sphenophorus parvulus

Bluegrass Billbug (Sphenophorus parvulus) Common Name: Bluegrass Billbug Latin Name: Sphenophorus parvulus Appearance:

• Eggs of Sphenophorus parvulus are bean-shaped (oblong) and off-white or cream-colored. Eggs are 1.4 to 1.6 mm in length and 0.6 mm in width.
• Larvae have a soft body, no legs, are off-white, and have a sclerotized (hardened) head capsule. The color of the head capsule ranges from whitish after hatching to dark red or brown as it ages. The fifth instar develops into a pre-pupa and actively builds an earthen cell in which to pupate.
• Pupae are delicate and off-white at first, becoming reddish brown right before the adult emerges. The nose of the pupa is visible, but the wings and legs are wrapped around the body’s midsection. Pupae range in size from 5.5 to 10 mm.
• Adult Sphenophorus parvulus may be identified by their distinctive snouts and brown-black coloration with consistently tiny pits in the pronotum. Teneral (newly emerging) adults have a reddish brown appearance that darkens when sclerotized. Adult body lengths range from 5 to 8 mm, with females having a mean length of 7.6 mm and males having a mean length of 6.9 mm. The elytra (wing coverings) have punctate furrows that produce striated lines akin to parallel chains. The antennae are geniculate (elbowed) and grow from the snout.

Host plant: Sphenophorus parvulus has become a major pest of Kentucky bluegrass, Poa pratensis L., and corn, Zea mays L. This insect also infects perennial ryegrass, Lolium perenne L.; tall fescue, Festuca arundinacea Schreb; barley, Secale cereal L.; Virginia orchardgrass, Hordeum vulgare L.; wheat, Triticum aestivum L; rye, Dactylis glomerata L.; and bentgrass, Agritis spp. Territory: It is found throughout North America, particularly in the eastern United States. Damages caused by Bluegrass Billbug: Both adults and larvae of Sphenophorus parvulus feed on or in grass stems, inflicting significant damage. Infection with harmful bacteria and fungi can cause secondary damage. Life history and habits: The adult beetle feeds on grass seedlings and fragile young stems. It appears to prefer Kentucky bluegrass as a host plant, although it will also feed on Timothy grass, redtop grass, maize, wheat, and other minor grain crops. Breeding occurs in the late spring, and there is only one generation. The acts of adults and larvae cause the plant to wilt and can cause it to be deformed, weakened, or even destroyed. The larva pupates, either in the stem or the soil, overwinters as an adult or pre-emergent adult inside the pupal case. Adult females can lay between 40 and 200 eggs in one to three months.